CHAPTER 25
Preoperative Evaluation and Postoperative Management
KEY POINTS
1 The preoperative evaluation should be complete and thorough, taking into account
the essential aspects of the patient’s general medical condition and prior surgical
history. The risks, benefits, and potential complications of the surgical procedure
should be discussed with the patient, including the most frequent complications of
the particular surgical procedure. Alternative management, if any, should be
presented.
2 A calculated body mass index (BMI) can be used as a surrogate marker for nutritional
status.
3 Careful and meticulous fluid and electrolyte management is essential for all patients
undergoing major surgical procedures.
4 Although satisfactory analgesia is easily achievable with available methods, patients
continue to suffer unnecessarily from postoperative pain.
5 Prophylactic antibiotics should be employed judiciously. Prompt identification of
perioperative infections and their specific treatments are critical to minimize the
impact of this common morbidity.
6 Enhanced recovery protocols are comprehensive and include preoperative,
intraoperative, and postoperative elements. Adherence to these protocols has
reduced hospital length of stay, postoperative complications, and health care costs.
7 Early in the clinical course, a postoperative small bowel obstruction may exhibit
signs and symptoms similar to those of an ileus. Initial conservative management as
outlined for the treatment of ileus is appropriate.
8 Because pulmonary embolism is the leading cause of death following gynecologic
surgical procedures, the use of prophylactic venous thromboembolism regimens is
an essential part of management. In patients at moderate risk, intermittent pneumatic
compression (IPC) during and after gynecologic surgery reduces the incidence of
deep venous thrombosis (DVT) on a level similar to that of low-dose or low–
molecular-weight heparin. A combination of mechanical (IPC) and pharmacologic
prophylaxis is recommended for high-risk patients.
9 Patients who are predisposed to cardiovascular, respiratory, and endocrine illnesses
must be thoroughly evaluated preoperatively. Coronary artery disease and chronic
obstructive pulmonary disease (COPD) are major risk factors for patients
undergoing abdominal surgery. Patients with hypertension should receive
medication to control their blood pressure before surgery. Perioperative management
1310of medical complications must be prompt and meticulous.
The successful outcome of gynecologic surgery is based on thorough evaluation,
careful preoperative preparation, and attentive postoperative care. This chapter
discusses the general perioperative management of patients undergoing major
gynecologic surgery and addresses specific medical problems that could
complicate the surgical outcome.
MEDICAL HISTORY AND PHYSICAL EXAMINATION
[1] Gynecologic surgery should be undertaken only after gaining a thorough
understanding of a patient’s medical history and performing a complete physical
examination.
1. The medical history should include detailed questions to identify any
medical illnesses that might be aggravated by surgery or anesthesia.
Coronary artery disease, diabetes, pulmonary diseases, and obesity are the
most common causes of postoperative complications.
2. Medications currently being taken (including nonprescription drugs) and
those discontinued within the month before surgery should be recorded.
Information about the use of “alternative therapies,” herbs, and vitamins
should be elicited (1,2). Specific instructions must be given to the patient
regarding the need to discontinue any medication before surgery (e.g., aspirin,
antiplatelet agents, diuretics, hormone replacement, or oral contraceptives),
and those medications that should be continued (e.g., β-blockers, α2-agonists,
statins, H2 blockers, and proton pump inhibitors). Collaboration with the
anesthesiologist in making decisions about continuing preoperative
medications is essential. In the case of herbal medications, there is no evidence
that herbal medications improve surgical outcomes and many may increase
complications (Table 25-1) (3). It is recommended that all herbal medications
be discontinued at least a week before surgery.
3. The patient should be questioned regarding known allergies to
medications (e.g., sulfa and penicillin), foods, or environmental agents
(latex).
4. Previous surgical procedures, and the patient’s course following those
surgical procedures, should be reviewed to identify and protect against
potential complications. The patient should be asked about specific
complications, such as excessive bleeding, wound infection, venous
thromboembolism, peritonitis, or bowel obstruction. Prior pelvic surgery
should alert the gynecologist to the possibility of distorted surgical anatomy
1311such as adhesions or ureteral stricture. In such cases, it may be prudent to
identify any pre-existing abnormality by performing computed tomography
(CT) or other imaging. Many patients may not be entirely clear about the
extent of the previous surgical procedure or the details of intraoperative
findings. Therefore, operative notes from previous procedures should be
obtained and reviewed.
5. Family history may identify familial traits that might complicate planned
surgery. A family history of excessive intra- or postoperative bleeding,
venous thromboembolism, malignant hyperthermia, and other potentially
inherited conditions should be sought.
6. The review of systems should be detailed to identify any coexisting
medical or surgical conditions. Inquiry about gastrointestinal and urologic
function is particularly important before undertaking pelvic surgery because
many gynecologic diseases involve adjacent nongynecologic viscera. The
patient may have less serious symptoms, which could be corrected along with
performing the primary surgery (e.g., stress urinary incontinence, fecal soiling,
symptomatic cystocele).
7. Although many women undergoing gynecologic surgical procedures are
otherwise healthy, with pathology identified only on pelvic examination,
other major organ systems should not be neglected in the physical
examination. Identification of abnormalities, such as a heart murmur,
pulmonary compromise, hernia, or osteoarthritis of hips or knees should lead
the surgeon to obtain additional testing and consultation to minimize intra- and
postoperative complications.
Table 25-1 Potential Effects of Common Herbal and Dietary Supplements
Herb/Dietary
Supplement
Potential Perioperative Effect
Aconite Potential ventricular arrhythmias
Aloe May potentiate thiazides
Black cohosh May potentiate hypotensive effects
Danshen May cause bleeding
Dong quai May cause bleeding
Echinacea Allergic reactions; decreased effectiveness of immunosuppressants
Ephedra/ma Risk of myocardial ischemia and stroke from tachycardia and
1312huang hypertension; ventricular arrhythmias with halothane; long-term use
may cause intraoperative hemodynamic instability; life-threatening
interaction with monoamine oxidase inhibitors, anesthesia, potential
for withdrawal
Garlic May increase bleeding risk
Ginkgo May increase bleeding risk
Ginseng Lowers blood sugar and may increase bleeding risk
Kava May increase the sedative effect of anesthetics (an association
between kava use and fatal hepatotoxicity has been reported)
Licorice May cause hypertension and hypokalemia
Senna May cause electrolyte imbalance
St. John’s wort Induction of cytochrome p450 enzyme; excessive sedation and
delayed emergence from general anesthesia; potential serotonin
syndrome if used in combination with other serotonergic agents
Valerian Excessive sedation and delayed emergence from general anesthesia;
benzodiazepine-like acute withdrawal
Yerba mate May cause hypertension or hypotension and excess sympathetic
nervous system stimulation
LABORATORY EVALUATION
“Routine” preoperative laboratory testing of healthy women is to be discouraged
as abnormal results are infrequent and are rarely of consequence in the surgical or
anesthetic management of the patient (4). Despite well-established guidelines,
approximately 90% of patients undergo unnecessary testing in a major university
medical center (5). The selection of appropriate preoperative laboratory studies
should depend on the type of the anticipated surgical procedure and the patient’s
medical status. The Revised Cardiac Risk Index (RCRI) can be used to predict the
risk of cardiac complications after noncardiac surgery. These clinical risk factors
include cerebrovascular disease, congestive heart failure (CHF), creatinine level
>2 mg/dL, and insulin-dependent diabetes.
Chest x-ray:
New or unstable cardiovascular or pulmonary signs or symptoms
At risk for pulmonary complications
Electrocardiogram:
1313Signs or symptoms of cardiovascular disease
High-risk surgery (risk of perioperative cardiac event >5%)
Intermediate-risk surgery (risk of perioperative cardiac event 1% to
5% and one RCRI clinical risk factor)
Complete blood count:
Major surgery
Patients with conditions with an increased risk for anemia
Renal function:
Recognized renal or cardiovascular disease
Coagulation studies (activated partial thromboplastin time [APTT],
prothrombin time [PT], platelet count):
Not recommended routinely
Patients with a history of bleeding or liver disease
Patients taking anticoagulants
History or examination concerning for an underlying coagulation
disorder
Urinalysis:
Not recommended routinely; may be considered, given symptoms or
history
Consider for invasive urologic procedures (6)
Tumor markers:
In general, tumor markers are used to follow patients with known
ovarian cancers. They are not considered “diagnostic.” However,
an elevated tumor marker in a patient with a “suspicious” pelvic
mass may be helpful in determining whether the patient should be
referred to a gynecologic oncologist (7).
Imaging of adjacent organ systems should be undertaken in individual cases as
follows:
1. CT urography is helpful to delineate ureteral patency and course, especially in
the presence of a pelvic mass, gynecologic cancer, or congenital müllerian
anomaly. A CT urogram is not of value in the evaluation of most patients
undergoing pelvic surgery.
2. Upper endoscopy, colonoscopy, barium enema, or upper gastrointestinal
studies with small bowel assessment may be of value in evaluating some
patients before undergoing pelvic surgery. Because of the proximity of the
female genital tract to the lower gastrointestinal tract, the rectum and sigmoid
colon may be involved with benign (endometriosis or pelvic inflammatory
disease) or malignant gynecologic conditions. Conversely, a pelvic mass could
have a gastrointestinal origin such as a diverticular abscess or a mass of
1314inflamed small intestines (Crohn disease) or, rarely, a gastric or pancreatic
carcinoma. Any patient with gastrointestinal symptoms should be further
evaluated.
3. Other imaging studies, including ultrasonography, CT scanning, or magnetic
resonance imaging (MRI), may be useful in selected patients, for example, to
evaluate a pelvic mass. There are several scoring systems that can be used in
the evaluation of a pelvic ultrasound that may suggest the increased likelihood
of ovarian cancer (8).
PREOPERATIVE DISCUSSION AND INFORMED CONSENT
[1] The preoperative discussion should include a description of the surgical
procedure, its expected outcome, and risks and is the basis for obtaining
signed informed consent (9,10). Informed consent is an educational process for
the patient and her family and fulfills the need to convey information in
understandable terms. The items listed in Table 25-2 should be discussed, and,
after each item, the patient and family should be invited to ask questions.
Documentation of the discussion is an important component of the patient’s
record that the physician should always include with the preprinted surgical
consent form.
Following are components of the informed consent process:
1. A discussion of the nature and the extent of the disease process should
include an explanation in lay terms of the significance of the disease or
condition. Printed materials, computer-based learning programs, and videos
may assist in this process. The patient’s competency to understand the
discussion and written consent should be assessed. If the patient speaks a
different language, a qualified interpreter should be present and the presence
of the interpreter documented.
2. The goals of proposed surgery should be discussed in detail. Some
gynecologic surgical procedures are performed purely for diagnostic purposes
(e.g., dilation and curettage, cold knife conization, diagnostic laparoscopy),
whereas most are aimed at correcting a specific problem. The extent of the
surgery should be outlined, including which organs will be removed. Most
patients like to be informed regarding the type of surgical incision and the
estimated duration of anesthesia.
3. The expected outcome of the surgical procedure should be explained. If
the procedure is being performed for diagnostic purposes, the outcome will
depend on surgical or pathologic findings that are not known before surgery.
When treating an anatomic deformity or disease, the expected success of the
1315operation should be discussed, and the potential for failure of the operation
(e.g., failure of tubal sterilization or the possibility that stress urinary
incontinence may not be alleviated, or may recur). When treating cancer, the
possibility of finding advanced disease and the potential need for adjunctive
therapy (e.g., postoperative radiation therapy or chemotherapy) should be
mentioned. Other issues of importance to the patient include discussion of loss
of fertility or loss of ovarian function. These issues should be raised by the
physician to ensure that the patient adequately understands the
pathophysiology that may result from the surgery and to allow her to express
her feelings regarding these issues. Unanticipated findings at the time of
surgery should be mentioned. For example, if the ovaries are unexpectedly
found to be diseased, the best surgical judgment may be that they should be
removed.
4. The risks and potential complications of the surgical procedure should be
discussed, including the most frequent complications of the particular
surgical procedure. For most major gynecologic surgeries, the risks include
intra- and postoperative hemorrhage, postoperative infection, venous
thromboembolism, injury to adjacent viscera, and wound complications. The
patient should understand that minimally invasive surgery, despite small skin
incisions, may have many of the same risks of injury or complications as does
“open” surgery. Given the potential for transfusion of blood products, it should
be clarified whether the patient would object to receiving a transfusion. Preexisting medical problems (e.g., diabetes, obesity, chronic obstructive
pulmonary disease [COPD], coronary artery disease) result in additional risks
and should be reviewed with the patient. Measures that will be taken to reduce
the risk of complications should be described (e.g., prophylactic antibiotics,
bowel preparation, venous thromboembolism prophylaxis).
5. The usual postoperative course should be discussed in enough detail to
allow the patient to understand what to expect in the days following
surgery. Information regarding the need for a suprapubic catheter, prolonged
central venous monitoring, or an intensive care stay helps the patient accept
her postoperative course and avoids surprises that may be disconcerting to the
patient and her family. The expected duration of the recovery period, in and
out of the hospital, should be outlined.
6. The surgeon should describe others who will be involved with the surgical
procedure (residents, assistants) and their roles in the patient’s care. Any
conflict of interest should be disclosed.
7. Alternative methods of therapy should be discussed, including medical
management or other surgical approaches. The potential risks and benefits
of alternative treatments should be discussed.
13168. The patient should have an understanding of the outcome of the disease.
Table 25-2 Outline of Key Points of the Preoperative Informed Consent Discussion
1. The nature and extent of the disease process
2. The extent of the actual operation proposed and the potential modifications of the
operation, depending on intraoperative findings
3. The anticipated benefits of the operation, with a conservative estimate of successful
outcome
4. The risks and potential complications of the surgery
5. Alternative methods of therapy and the risks and results of those alternative methods
of therapy
6. The results likely, if the patient is not treated
GENERAL CONSIDERATIONS
Nutrition
Young patients undergoing elective gynecologic surgery have adequate
nutritional stores and, for the most part, do not require nutritional support. All
patients should have a nutritional assessment, especially elderly patients and
those undergoing gynecologic cancer surgery or other major gynecologic
procedures in which a prolonged postoperative recovery is expected.
Nutritional status should be reassessed at regular intervals postoperatively until
the patient successfully returns to a regular diet.
A nutritional assessment includes a careful history and physical examination,
which are the most useful, reliable, and cost-effective methods of determining a
patient’s nutritional status. In particular, information about recent weight loss,
dietary history, fad diets, extreme exercise, or anorexia or bulimia should be
elucidated. Physical evidence of malnutrition, including temporal wasting, muscle
wasting, ascites, and edema, should be noted. Accurate height and weight
measurements should be obtained and an ideal body weight, percentage ideal
body weight, and percentage usual body weight may be calculated. A variety of
techniques were developed to determine a patient’s nutritional state; however,
many methods lack clinical utility outside of a research setting. Anthropometric
measurements of skin-fold thickness and arm-muscle circumference provide an
estimate of total body fat and lean muscle mass. Nutritional screening
assessments, such as the Mini Nutritional Assessment and the Prognostic
1317Nutritional Index, have been described to evaluate a patient’s nutritional status
(11).
[2] The calculated body mass index (BMI) can be used as a surrogate marker for
nutritional status. BMI is calculated as body weight in kilograms divided by
the height in square meters. A BMI less than 22 increases the risk of
malnutrition, and a BMI less than 19 gives clear evidence of malnutrition
(12). The degree of malnutrition can in part be determined by serum
concentrations of albumin, transferrin, and prealbumin. The levels of these serum
proteins are greatly influenced by the patient’s level of hydration. Prealbumin has
the shortest half-life, at 2 to 3 days, and levels of this protein are depressed very
early in comparison with serum transferrin and albumin, which have half-lives of
8 and 20 days, respectively (14). Serum albumin is a substitute for the Prognostic
Nutritional Index, which is a time-consuming calculation, in assessing
malnutrition in women with gynecologic malignancies (15). Hypoalbuminemia,
characterized by an albumin of less than 3.5 g/dL, is correlated with
morbidity, mortality, and increased postoperative complication rates in data
from the National Surgical Quality Improvement Program (13). Proteinenergy malnutrition, as characterized by hypoalbuminemia, can result in poor
wound healing, increased risk for infection, functional decline, increased
morbidity and mortality.
Decisions regarding the need for nutritional support should be based on several
individualized factors. These factors include the patient’s prior nutritional state,
the anticipated length of time in which the patient will not be able to eat, the
extent of surgery, and the likelihood of complications. The nutritional assessment
should determine whether the cause of the malnutrition is increased enteral loss
(malabsorption, intestinal fistula), decreased oral intake, increased nutritional
requirements as a result of hypermetabolism (sepsis, malignancy), or a
combination of these factors. Severe malnutrition, if not corrected, can further
complicate the postoperative problem by causing altered immune function,
chronic anemia, impaired wound healing, and eventually multiple organ system
failure and death.
There is evidence that preoperative nutritional support may improve
postoperative outcomes in patients with significant pre-existing malnutrition
(16,17). According to the American Society for Parenteral and Enteral
Nutrition (ASPEN) guidelines, evidence-based medicine supports the use of
preoperative nutritional support for 7 to 14 days in severely malnourished
patients undergoing major nonemergent gastrointestinal surgery (14).
Preoperative oral supplementation may reduce infectious complications and
shorten hospital stays, however the effect on mortality is unclear (18). ASPEN
guidelines do not support the routine use of parenteral nutritional support in the
1318immediate postoperative period for patients undergoing major gastrointestinal
surgery; however, the guidelines do indicate a role for nutritional support
postoperatively in patients in whom oral intake will be inadequate for 7 to 10 days
(14).
Antimicrobial Prophylaxis in Gynecologic Surgery
Gynecologic procedures often involve breaching the reproductive and
gastrointestinal tracts, which harbor endogenous bacteria capable of causing
polymicrobial infections in the postoperative period (Table 25-3). Despite great
advances in aseptic technique and drug development, bacterial
contamination of the operative site and postoperative infections are a
frequent part of the practice of gynecologic surgery. Prevention of these
surgical complications includes using proper aseptic technique, minimizing tissue
trauma, minimizing the amount of foreign material in the surgical site, controlling
diabetes, avoiding immunologic suppression, maximizing tissue oxygenation,
draining blood and serum from the surgical site, and using prophylactic
antibiotics. [5] Antibiotic prophylaxis is given with the belief that antibiotics
enhance the immune mechanisms in host tissues that resist infections by killing
the bacteria that inoculate the surgical site during surgery (19).
Table 25-3 Bacteria Indigenous to the Lower Genital Tract
Lactobacillus Enterobacter agglomerans
Diphtheroids Klebsiella pneumoniae
Staphylococcus aureus Proteus mirabilis
Staphylococcus epidermidis Proteus vulgaris
Streptococcus agalactiae Morganella morganii
Streptococcus faecalis Citrobacter diversus
α-Hemolytic streptococci Bacteroides species
B. disiens
B. fragilis
B. melaninogenicus
Group D streptococci
Peptostreptococci
Peptococcus
Clostridium
1319Gaffkya anaerobia
Escherichia coli
Fusobacterium
Enterobacter cloacae
Infections in the skin or pelvis that result from gynecologic surgery (e.g.,
parametritis, cuff cellulitis, pelvic abscess) typically are polymicrobial in nature.
These infections are complex and often involve gram-negative rods, grampositive cocci, and anaerobes. Antibiotic prophylaxis should be sufficiently broad
to cover these potential pathogens (Table 25-4) (20).
The timing of antimicrobial prophylaxis is important. There is a relatively
narrow window of opportunity for affecting outcomes (21). In the United
States, it is customary to give antimicrobial prophylaxis shortly before or during
the induction of anesthesia. Data revealed that a delay of 3 hours or more
between the time of bacterial inoculation (i.e., skin incision) and
administration of antibiotics may result in ineffective prophylaxis. Evidence
indicates that for prophylaxis, one dose of antibiotic is appropriate. When
the surgical procedure proceeds longer than 1 to 2 times the half-life of the
drug or blood loss is greater than 1.5 L, additional intraoperative doses of
antibiotics should be administered to maintain adequate levels of medication
in serum and tissues (22). There are no data to support the continuation of
prophylactic antimicrobial agents into the postoperative period for routine
gynecologic procedures.
Cephalosporins emerged as the most important class of antimicrobial
agents for prophylaxis. These drugs have a broad spectrum and relatively low
incidence of adverse reactions. Cefazolin (1 g) appears to be widely used in the
United States by gynecologic surgeons because of its relatively low cost and long
half-life (1.8 hours). Other cephalosporins such as cefoxitin, cefotaxime, and
cefotetan are commonly used for prophylaxis. These agents appear to have a
broader spectrum of activity against anaerobic bacteria and are appropriate
selections when colorectal resections are possible, such as during a debulking
surgery for ovarian cancer. For the majority of gynecologic procedures, there is
little evidence that a clinically relevant distinction exists between cefazolin and
the other agents. Obese patients, defined as having a BMI greater than 35 or
weight greater than 100 kg, should receive 2 g of cefazolin to achieve appropriate
blood and tissue antibiotic concentrations (20).
Table 25-4 Antibiotic Prophylaxis Regimens by Procedure
1320Procedure Antibiotic Dose
Hysterectomy
Urogynecology
procedures, including
those involving mesh
Cefazolina
Clindamycinc plus
gentamicin or
quinoloned or
aztreonam
Metronidazolec plus
gentamycin or
quinoloned
1 g or 2 g IVb 600 mg IV 1.5 mg/kg IV
400 mg IV 1 g IV 500 mg IV 1.5
mg/kg IV 400 mg IV 1 g IV
Hysterosalpingogram
or Chromotubation
Doxycyclinee 100 mg orally, twice daily for 5 days
Induced
abortion/dilation and
evacuation
Doxycycline
Metronidazole
100 mg orally 1 hr before procedure
and 200 mg orally after procedure
500 mg orally twice daily for 5 days
aAlternatives include cefotetan, cefoxitin, cefuroxime, or ampicillin–sulbactam.
b
A 2-g dose is recommended in women with a body mass index greater than 35 or weight
greater than 100 kg or 220 lb.
cAntimicrobial agents of choice in women with a history of immediate hypersensitivity to
penicillin.
d
Ciprofloxacin or levofloxacin or moxifloxacin.
eIf patient has a history of pelvic inflammatory disease or procedure demonstrates dilated
fallopian tubes. No prophylaxis is indicated for a study without dilated tubes.
IV, intravenously.
Adapted from Antibiotic prophylaxis for gynecologic procedures. American College of
Obstetricians and Gynecologists Practice Bulletin No. 104, May 2009.
Antimicrobial prophylaxis, although usually beneficial, is not without risk.
Anaphylaxis is the most life-threatening complication from antibiotic use.
Allergic reactions to penicillins are reported in 0.7% to 8% courses of
treatment (23). While first-generation cephalosporins have cross-reactivity to
penicillins, data indicate that it is safe to administer second- or third-generation
cephalosporins to women who report a history of adverse reactions to penicillins
as the cross-allergy is negligible (24).
A single dose of broad-spectrum antibiotics can result in
pseudomembranous colitis, caused by Clostridium difficile. Diarrhea may
develop in as many as 15% of hospitalized patients treated with β-lactam
antibiotics (25). These gastrointestinal complications from antibiotics may cause
1321serious morbidity in the surgical patient, and the surgeon should be able to
recognize and manage these problems.
Not all gynecologic surgery patients need to receive prophylactic
antibiotics. The surgeon should choose agents to cover procedures based on
available data, thereby avoiding the potential for adverse reactions and
minimizing the unnecessary use of antibiotics, which may contribute to increased
rates of antimicrobial resistance. In patients with cephalosporin allergies or
anaphylaxis to penicillin, other drugs or combinations should be chosen to
provide adequate prophylactic coverage. Antimicrobial prophylaxis options for
common gynecologic procedures are presented in Table 25-3. Antibiotic
prophylaxis is not indicated for diagnostic or operative laparoscopy, exploratory
laparotomy, or diagnostic or operative hysteroscopy, including endometrial
ablation, intrauterine device insertions, endometrial biopsy, or urodynamics (20).
Subacute Bacterial Endocarditis Prophylaxis
It was thought that women who had severe valvular disease or other cardiac
conditions required antibiotic prophylaxis prior to genitourinary (GU) or
gastrointestinal (GI) procedures in order to prevent bacterial endocarditis as a
result of the transient bacteremia provoked by the surgery. After reviewing the
pertinent evidence-based literature, the American Heart Association (AHA)
issued revised guidelines in 2007 stating that antibiotic prophylaxis was not
necessary solely to prevent endocarditis in patients undergoing GI or GU
procedures, including hysterectomy (26). For those at highest risk of infective
endocarditis undergoing high-risk procedure, antibiotics should still be considered
(Table 25-5).
Postoperative Infections
Infections are a major source of morbidity in the postoperative period. Risk
factors for infectious morbidity include the absence of perioperative antibiotic
prophylaxis, contamination of the surgical field from infected tissues or from
spillage of large bowel contents, an immunocompromised host, poor nutrition,
chronic and debilitating severe illness, poor surgical technique, and pre-existing
focal or systemic infection. Sources of postoperative infection can include the
lung, urinary tract, surgical site, pelvic sidewall, vaginal cuff, abdominal wound,
and sites of indwelling intravenous catheters. Early identification and treatment of
infection will result in the best outcome for these potentially serious
complications.
Table 25-5 Recommendations for Prophylaxis of Bacterial Endocarditis
1322Highest-Risk
Patients
Agents Regimen (Within 30–60 min of
Starting Procedure)
Standard regimen Amoxicillin 2 g PO
Ampicillin 2 g IM or IV
or
Cefazolin or
ceftriaxone
1 g IM or IV
Cephalexin 2 g
Penicillin-allergic
(oral)
Cephalexin 2 g
Clindamycin 600 mg
Azithromycin or
clarithromycin
500 mg
Penicillin-allergic
(non-oral)
Cefazolin or
ceftriaxone
1 g IM or IV
Clindamycin 600 mg IM or IV
IM, intramuscularly; IV, intravenously.
Derived from Wilson W, Taubert KA, Gewitz M, et al. Prevention of infective
endocarditis: guidelines from the American Heart Association: a guideline from the
American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease
Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical
Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care
and Outcomes Research Interdisciplinary Working Group. Circulation 2007;116:1736–
1754.
Although infectious morbidity is a frequent complication of surgery, the
incidence of infections can be decreased by the appropriate use of simple
preventive measures. Systemic antibiotic prophylaxis and meticulous surgical
technique will help decrease the incidence of postoperative pelvic and abdominal
infections in these patients. Blood and necrotic tissue are excellent media for the
growth of aerobic and anaerobic organisms. Care should be taken to obtain
hemostasis to prevent postoperative hematomas. Antibiotic therapy, rather than
prophylaxis, should be initiated during surgery in patients who have frank intraabdominal infection or pus. Elective surgical procedures should be postponed in
patients who have preoperative infections. In an epidemiologic study conducted
1323by the Centers for Disease Control and Prevention (CDC), the incidence of
nosocomial surgical infections ranged from 4.3% in community hospitals to 7%
in municipal hospitals (27). Data confirmed this, with an incidence of 2% to 5%
(28). Urinary tract infections accounted for approximately 40% of these
nosocomial infections. Infections of the skin and wound accounted for
approximately one-third of the infections, and respiratory tract infections
accounted for approximately 16%. In patients who had any type of infection
before surgery, the risk of infection at the surgical wound site increased fourfold.
Rates of infection were higher in older patients, in patients with increased length
of surgery, and in those with increased length of hospital stay before surgery. The
relative risk was three times higher in patients with a community-acquired
infection before surgery. These community-acquired infections included
infections of the urinary and respiratory tracts.
Historically, the standard definition of febrile morbidity for surgical
patients was the presence of a temperature higher than or equal to 100.4°F
(38°C) on two occasions at least 4 hours apart during the postoperative
period, excluding the first 24 hours. Other sources defined fever as two
consecutive temperature elevations greater than 101.0°F (38.3°C) (29,30).
Febrile morbidity is estimated to occur in as many as one-half of patients; it is
often self-limited, resolves without therapy, and is usually noninfectious in origin
(31). Overzealous evaluations of postoperative fever, especially during the early
postoperative period, are time consuming, expensive, and sometimes
uncomfortable for the patient (31). The value of 101.0°F is more discriminatory
than 100.4°F to distinguish an infectious cause from an inconsequential
postoperative fever in the benign gynecologic patient.
The assessment of a febrile surgical patient should include a review of the
patient’s history with regard to risk factors. The history and the physical
examination should focus on the potential sites of infection (Table 25-6). The
examination should include inspection of the pharynx, a thorough pulmonary
examination, percussion of the kidneys to assess for costovertebral angle
tenderness, inspection and palpation of the abdominal incision, examination of
sites of intravenous catheters, and an examination of the extremities for evidence
of deep venous thrombosis (DVT) or thrombophlebitis. In gynecologic patients,
an appropriate workup may include inspection and palpation of the vaginal cuff
for signs of induration, tenderness, or purulent drainage. A pelvic examination
should be performed to identify a mass consistent with a pelvic hematoma or
abscess and to look for signs of pelvic cellulitis.
Patients with fever in the early postoperative period should have an
aggressive pulmonary toilet, including incentive spirometry (30). [5] Fever
within the first 48 hours of surgery is likely to be cytokine related; thus if fever
1324persists beyond 48 hours postoperatively, additional laboratory and radiologic
data may be obtained. The evaluation may include complete and differential white
blood cell counts and a urinalysis. In one study, results from fever workups
included positive blood cultures in 9.7% of patients, a positive urine culture in
18.8%, and a positive chest x-ray in 14%. These data support the need for a
tailored workup based on the patient’s clinical picture (32). Blood cultures can be
obtained but will most likely be of little yield unless the patient has fever at the
time of collection. In patients with costovertebral angle tenderness, renal
ultrasound or CT urogram may be indicated to rule out the presence of ureteral
damage or obstruction from surgery, particularly in the absence of laboratory
evidence of urinary tract infection. Patients who have persistent fevers without a
clear localizing source should undergo CT scanning of the abdomen and pelvis to
rule out the presence of an intra-abdominal abscess. If fever persists in patients
who had gastrointestinal surgery, a barium enema or upper gastrointestinal studies
with small bowel assessment may be indicated late in the course of the first
postoperative week to rule out an anastomotic leak or fistula.
Table 25-6 Posthysterectomy Infections
Operative Site Nonoperative Site
Vaginal cuff Urinary tract
Pelvic cellulitis Asymptomatic bacteriuria
Pelvic abscess Cystitis
Intraperitoneal Respiratory
Adnexa Atelectasis
Cellulitis Pneumonia
Abscess Vascular
Abdominal incision Phlebitis
Cellulitis Septic pelvic thrombophlebitis
Simple Pyelonephritis
Progressive bacterial synergistic
Necrotizing fasciitis
1325Myonecrosis
Urinary Tract Infections
Historically, the urinary tract was the most common site of infection in surgical
patients (33). A significant decrease in urinary tract infections was noted after the
institution of perioperative use of prophylactic antibiotics. The incidence of
postoperative urinary tract infection in gynecologic surgical patients not receiving
prophylactic antibiotics is thought to be as high as 40%, and even a single dose of
perioperative prophylactic antibiotic decreases the incidence of postoperative
urinary tract infection to as low as 4% (34,35).
Symptoms of a urinary tract infection may include urinary frequency, urgency,
and dysuria. In patients with pyelonephritis, patients may exhibit systemic
symptoms such as headache, malaise, nausea, and vomiting. A urinary tract
infection is diagnosed on the basis of microbiology and is defined as the growth
of 105 organisms cultured per milliliter of a voided specimen urine. Most
infections are caused by coliform bacteria, with Escherichia coli being the most
frequent pathogen. Other pathogens include Klebsiella, Proteus, and Enterobacter
species. Staphylococcus organisms are the causative bacteria in fewer than 10%
of cases.
Despite the high incidence of urinary tract infections in the postoperative
period, few of these infections are serious. Most are confined to the lower urinary
tract, and pyelonephritis is a rare complication (36). Catheterization of the urinary
tract, either intermittently or continuously with the use of an indwelling catheter,
is implicated as a main cause of urinary tract contamination (37). More than 1
million catheter-associated urinary tract infections occur yearly in the United
States, and catheter-associated bacteria remain the most common etiology of
gram-negative bacteremia in hospitalized patients. Bacteria adhere to the
surface of urinary catheters and grow within bile films, which appear to protect
embedded bacteria from antibiotics, making treatment less effective. The use of
urinary tract catheters should be minimized. An indwelling catheter should be
removed or replaced in a patient undergoing treatment for catheter-related
infections.
The treatment of urinary tract infection includes hydration and antibiotic
therapy. Infections may be considered complicated or uncomplicated which
helps providers dictate the type and length of therapy. Infections are considered
complicated if they occur in patients with poorly controlled diabetes,
immunosuppression, pregnancy, kidney disease, urinary obstruction, anatomic
abnormality of the genitourinary tract, recent hospitalization, or those with an
indwelling catheter, stent, or nephrostomy tube (38). Commonly prescribed and
1326effective antibiotics include penicillin, sulfonamides, cephalosporins,
fluoroquinolones, and nitrofurantoin (39). The choice of antibiotic should be
based on knowledge of the susceptibility of organisms cultured at a particular
institution. In some institutions, for example, more than 40% of E. coli strains are
resistant to ampicillin. For uncomplicated urinary tract infections, an antibiotic
that has good activity against E. coli should be given in the interim while awaiting
results of the urine culture and sensitivity data.
Patients who have a history of recurrent urinary tract infections, those with
chronic indwelling catheters (Foley catheters or ureteral stents), and those who
have urinary conduits should be treated with antibiotics that will be effective
against the less common urinary pathogens such as Klebsiella and Pseudomonas.
Chronic use of fluoroquinolones for prophylaxis is not advised because these
agents are notorious for inducing antibiotic-resistant strains of bacteria.
Pulmonary Infections
The respiratory tract is an uncommon site for infectious complications in
gynecologic surgical patients. This low incidence is probably a reflection of the
young age and good health status of gynecologic patients in general. In acute care
facilities, pneumonia is a frequent hospital-acquired infection, particularly in
elderly patients (40). Risk factors include extensive or prolonged atelectasis,
preexistent COPD, severe or debilitating illness, central neurologic disease
causing an inability to clear oropharyngeal secretions effectively, nasogastric
suction, and a prior history of pneumonia (40,41). In surgical patients, early
ambulation and aggressive management of atelectasis are the most important
preventive measures.
A significant percentage (40% to 50%) of cases of hospital-acquired
pneumonia is caused by gram-negative organisms (33). These organisms gain
access to the respiratory tract from the oral pharynx. Gram-negative colonization
of the oral pharynx is increased in patients in acute care facilities and is associated
with the presence of nasogastric tubes, pre-existing respiratory disease,
mechanical ventilation, and tracheal intubation (42). The use of antimicrobial
drugs seems to significantly increase the frequency of colonization of the oral
pharynx with gram-negative bacteria.
A thorough lung examination should be included in the assessment of all
febrile surgical patients. In the absence of significant lung findings, chest
radiography is probably of little benefit in patients at low risk for postoperative
pulmonary complications. In patients with pulmonary findings or with risk factors
for pulmonary complications, chest radiography should be performed. A sputum
sample should be obtained for Gram stain and culture. The treatment should
include postural drainage, aggressive pulmonary toilet, and antibiotics. The
1327antibiotic chosen should be effective against gram-positive and gram-negative
organisms. In patients who are receiving assisted ventilation, the antibiotic
spectrum should include drugs that are active against Pseudomonas organisms.
Phlebitis
Historically, intravenous catheter–related infections were common; the reported
incidence is 25% to 35% in the 1980s (43). Because the incidence of catheterrelated phlebitis increases significantly after 72 hours, intravenous catheters
should be changed after 72 to 96 hours with special care to examine the site and
dressing daily (44).
The catheter should be removed if there is any associated pain, redness, or
induration. Phlebitis can occur even with close surveillance of the intravenous
site. In one study, more than 50% of the cases of phlebitis became evident more
than 12 hours after discontinuation of intravenous catheters (45). Less than onethird of patients had symptoms related to the intravenous catheter site 24 hours
before the diagnosis of phlebitis.
Phlebitis can be diagnosed based on the presence of fever, pain, redness,
induration, or a palpable venous cord. Occasionally, suppuration will be present.
Phlebitis is usually self-limited and resolves within 3 to 4 days. The treatment
includes application of warm, moist compresses and prompt removal of any
catheters from the infected vein. Antibiotic therapy with antistaphylococcal
agents should be instituted for catheter-related sepsis. Excision or drainage of an
infected vein rarely is necessary.
Wound Infections
The results of a prospective study of more than 62,000 wounds were revealing in
regard to the epidemiology of wound infections (46). The wound infection rate
varied markedly, depending on the extent of contamination of the surgical field.
The wound infection rate for clean surgical cases (infection not present in the
surgical field, no break in aseptic technique, no viscus entered) was lower than
2%, whereas the incidence of wound infections with dirty, infected cases was
40% or higher. Preoperative showers with hexachlorophene slightly lowered the
infection rate for clean wounds, whereas preoperative shaving of the wound site
with a razor increased the infection rate. The wound infection rate increased with
the duration of preoperative hospital stay and with the duration of surgery.
Incidental appendectomy increased the risk of wound infection in patients
undergoing clean surgical procedures. The study concluded that the incidence of
wound infections could be decreased by short preoperative hospital stays,
hexachlorophene showers before surgery, minimizing shaving of the wound
site, use of meticulous surgical technique, decreasing operative time as much
1328as possible, bringing drains out through sites other than the wound, and
dissemination of information to surgeons regarding their wound infection
rates. A program instituting these conclusions led to a decrease in the clean
wound infection rate from 2.5% to 0.6% over an 8-year period. The wound
infection rate in most gynecologic services is lower than 5%, reflective of the
clean nature of most gynecologic operations.
The symptoms of wound infection often occur late in the postoperative
period, usually after the fourth postoperative day, and may include fever,
erythema, tenderness, induration, and purulent drainage. Wound infections
that occur on postoperative days 1 through 3 are generally caused by
streptococcal and Clostridia infections. The management of wound infections is
mostly mechanical and involves opening the infected portion of the wound above
the fascia, with cleansing and debridement of the wound edges as necessary.
Wound care, consisting of debridement and dressing changes two to three times
daily, will promote growth of granulation tissue, with gradual filling in of the
wound defect by secondary intention. Clean, granulating wounds can often be
secondarily closed with good success, shortening the time required for complete
wound healing.
Pelvic Cellulitis
Vaginal cuff cellulitis is present in most patients who undergo hysterectomy.
It is characterized by erythema, induration, and tenderness at the vaginal cuff. A
purulent discharge from the apex of the vagina may be present. The cellulitis is
often self-limited and does not require any treatment. Fever, leukocytosis, and
pain localized to the pelvis may accompany severe cuff cellulitis and most often
signifies extension of the cellulitis to adjacent pelvic tissues. In such cases, broadspectrum antibiotic therapy should be instituted with coverage for gram-negative,
gram-positive, and anaerobic organisms. If purulence at the vaginal cuff is
excessive or if there is a fluctuant mass noted at the vaginal cuff, the vaginal cuff
should be gently probed and opened with a blunt instrument. The cuff can be left
open for dependent drainage or, alternatively, a drain can be placed into the lower
pelvis through the cuff and removed when drainage, fever, and symptoms in the
lower pelvic region have resolved.
Intra-Abdominal and Pelvic Abscess
The development of an abscess in the surgical field or elsewhere in the abdominal
cavity is an uncommon complication after a gynecologic surgery. It is likely to
occur in contaminated cases in which the surgical site is not adequately drained or
as a secondary complication of hematomas. The causative pathogens in patients
who have intra-abdominal abscesses are usually polymicrobial in nature. The
1329aerobes most commonly identified include E. coli, Klebsiella, Streptococcus,
Proteus, and Enterobacter. Anaerobic isolates are common, usually from the
Bacteroides group. These pathogens arise mainly from the vaginal tract but can be
derived from the gastrointestinal tract, particularly when the colon was entered at
the time of surgery.
Intra-abdominal abscess may be difficult to diagnose. The evolving clinical
picture is often one of persistent febrile episodes with a rising white blood cell
count. Findings on abdominal examination may be equivocal. If an abscess is
located deep in the pelvis, it may be palpable by pelvic or rectal examination. CT
scanning is more sensitive and specific than ultrasonography for diagnosing
intra-abdominal abscesses and often is the radiologic procedure of choice.
Standard therapy for intra-abdominal abscess is evacuation and drainage
combined with appropriate administration of antibiotics. Abscesses located
low in the pelvis, particularly in the area of the vaginal cuff, can be reached
through a vaginal approach. In many patients, the ability to drain an abscess by
placement of a drain percutaneously under CT guidance obviated the need for
surgical exploration. With CT guidance, a pigtail catheter is placed into an
abscess cavity via transabdominal, transperineal, transrectal, or transvaginal
approaches. The catheter is left in place until drainage output decreases.
Transperineal and transrectal drainage of deep pelvic abscesses are successful in
90% to 93% of patients, obviating the need for surgical management (47,48). For
those patients in whom radiologic drainage is not successful, surgical
exploration and evacuation are indicated. The standard approach to initial
antibiotic therapy is to employ broad-spectrum parenteral antibiotic therapy with
both aerobic and anaerobic coverage (49). There are several acceptable regimens
including piperacillin–tazobactam, or clindamycin with ceftriaxone, or
metronidazole with ceftriaxone, or ertapenem, or ticarcillin–clavulanate, or
aztreonam with clindamycin (for those who have a penicillin allergy) (49).
Parenteral antibiotics can be transitioned to oral therapy when clinical
improvement is noted (WBC improving, afebrile for 48 hours, and abscess is
shrinking). Oral antibiotics should be tailored to culture results.
Necrotizing Fasciitis
Necrotizing fasciitis is an uncommon infectious disorder, affecting roughly
1,000 patients per year (50). This disease process is characterized by a rapidly
progressive bacterial infection that involves the subcutaneous tissues and fascia
while characteristically sparing underlying muscle. Systemic toxicity is a frequent
feature of this disease, as manifested by the presence of dehydration, septic shock,
disseminated intravascular coagulation, and multiple organ system failure.
There are two forms of necrotizing fasciitis, type I and type II. Type I
1330infections are caused by mixed aerobic and anaerobic bacteria and occur in
patients with risk factors such as recent surgery, diabetes, or immune
compromise. Type II infections are a result of β-hemolytic streptococci and can
occur in healthy patients who have a predisposing injury, such as a skin laceration
(51). Bacterial enzymes such as hyaluronidase and lipase released in the
subcutaneous space destroy the fascia and adipose tissue and induce a liquefactive
necrosis. Noninflammatory intravascular coagulation or thrombosis subsequently
occurs. Intravascular coagulation results in ischemia and necrosis of the
subcutaneous tissues and skin. Subcutaneous spread of up to 1 inch per hour can
be seen, often with little effect on the overlying skin (52). Late in the course of
the infection, destruction of the superficial nerves produces anesthesia in the
involved skin. The release of bacteria and bacterial toxins into the systemic
circulation can cause septic shock, acid–base disturbances, and multiple organ
impairment.
The diagnosis is often difficult to make early in the disease course. Most
patients with necrotizing fasciitis develop erythema, edema, and pain, which
in the early stages of the disease are disproportionately greater than that
expected from the degree of cellulitis present and characteristically extend
beyond the border of erythema (51). Late in the course of the infection, the
involved skin may be anesthetized secondary to necrosis of superficial nerves.
Temperature abnormalities, both hyperthermia and hypothermia, are concomitant
with the release of bacterial toxins and with bacterial sepsis (52). The involved
skin is initially tender, erythematous, and warm. Edema develops, and the
erythema spreads diffusely, fading into normal skin, characteristically without
distinct margins or induration. Subcutaneous microvascular thrombosis induces
ischemia in the skin, which becomes cyanotic and blistered. As necrosis develops,
the skin becomes gangrenous and may slough spontaneously (52). Most patients
will have leukocytosis and acid–base abnormalities. Subcutaneous gas may
develop, which can be identified by palpation and radiography. The finding of
subcutaneous gas by radiography is often indicative of clostridial infection,
although it is not a specific finding and may be caused by other organisms. These
organisms include Enterobacter, Pseudomonas, anaerobic streptococci, and
Bacteroides, which, unlike clostridial infections, spare the muscles underlying the
affected area.
Successful management of necrotizing fasciitis involves early recognition,
immediate initiation of resuscitative measures (including correction of fluid,
acid–base, electrolyte, and hematologic abnormalities), aggressive surgical
debridement and redebridement as necessary, and broad-spectrum
intravenous antibiotic therapy (52). During surgery, the incision should be
made through the infected tissue down to the fascia. An ability to undermine the
1331skin and subcutaneous tissues with digital palpation often will confirm the
diagnosis. Excision of infected, necrotic tissue should extend toward the
periphery of the affected tissue until well-vascularized, healthy, resistant tissue is
reached at all margins. The remaining affected tissue must be excised. The wound
can be packed and sequentially debrided as necessary until healthy tissue is
displayed at all margins. Hyperbaric oxygen therapy may be of some benefit,
particularly in patients for whom culture results are positive for anaerobic
organisms (53). Retrospective nonrandomized studies demonstrated that the
addition of hyperbaric oxygen therapy to surgical debridement and antimicrobial
therapy appear to significantly decrease wound morbidity and overall mortality in
patients with necrotizing fasciitis (53). After the initial resuscitative efforts and
surgical debridement, the primary concern is the management of the open wound.
Allograft and xenograft skin can be used to cover open wounds, thus decreasing
heat and evaporative water loss.
Significant improvement in wound healing may be aided by a vacuum-assisted
closure (VAC) method that uses a subatmospheric pressure technique (54). In
situations in which spontaneous closure is not likely, the VAC device may permit
the development of a suitable granulation bed and prepare the tissue for graft
placement, thereby increasing the probability of graft survival. Skin flaps can be
mobilized to help cover open wounds when the infection resolves and granulation
begins.
Postoperative Gastrointestinal Complications
Ileus
Following open abdominal or pelvic surgery, most patients experience some
degree of intestinal ileus. The exact mechanism by which this arrest and
disorganization of gastrointestinal motility occurs is unknown, but it appears to be
associated with the opening of the peritoneal cavity and is aggravated by
manipulation of the intestinal tract, intestinal resection, and prolonged surgical
procedures. Infection, peritonitis, opioids, and electrolyte disturbances may result
in ileus. For most patients undergoing common gynecologic operations, the
degree of ileus is minimal, and gastrointestinal function returns relatively rapidly,
allowing the resumption of oral intake within 12 hours of surgery. Ileus is
reported in 3% of patients undergoing total abdominal hysterectomy (55). Patients
who have intolerance for oral intake, persistently diminished bowel sounds,
abdominal distension, absence of flatus, nausea, or vomiting require further
evaluation. Patients with symptoms of ileus or small bowel obstruction who
underwent minimally invasive surgery are a different matter. Minimally
invasive surgery should result in a daily improvement in GI function. An
1332“ileus” in the case of minimally invasive surgery more likely represents GI
injury, which should be evaluated immediately with a CT scan using GI
contrast.
Ileus is usually manifested by abdominal distension with nausea and/or
vomiting and should be evaluated by physical examination. Pertinent points of the
abdominal examination include assessment of the quality of bowel sounds and
palpation in search of distension, tympany, masses, diffuse tenderness, or
rebound. The possibility that the patient’s signs and symptoms may be associated
with a more serious intestinal obstruction or intestinal complication (such as a
perforation) must be considered. Pelvic examination should be performed to
evaluate the possibility of a pelvic abscess or hematoma that may contribute to the
ileus. Abdominal radiography to evaluate the abdomen in the flat (supine)
position and in the upright position will aid in the diagnosis of an ileus. The
most common radiographic findings include dilated loops of small and large
bowel and air–fluid levels while the patient is in the upright position. Air
should be present in the colon or rectum. In the postoperative gynecology
patient, especially in the upright position, the abdominal x-ray may show free air.
This common finding following surgery lasts 7 to 10 days in some instances and
is not necessarily indicative of a perforated viscus in most patients.
The initial management of a postoperative ileus is aimed at gastrointestinal
tract decompression and maintenance of appropriate intravenous replacement
fluids and electrolytes.
1. The patient should be made NPO status (nothing by mouth) with
intravenous (IV) fluids and electrolytes. If nausea and vomiting persist, a
nasogastric tube should be used to evacuate the stomach of its fluid and
gaseous contents. Continued nasogastric suction removes swallowed air,
which is the most common source of gas in the small bowel.
2. Laboratory evaluation should include CBC, serum electrolytes, creatinine
and blood urea nitrogen (BUN), and liver functions.
3. Fluid and electrolyte replacement must be adequate to keep the patient
well hydrated and in metabolic balance. Significant amounts of third-space
fluid loss occur in the bowel wall, the bowel lumen, and the peritoneal cavity
during the acute episode. Gastrointestinal fluid losses from the stomach may
lead to metabolic alkalosis and depletion of other electrolytes. Careful
monitoring of serum chemistry levels and appropriate replacement are
necessary.
4. Most cases of severe ileus begin to improve over a period of several days.
This improvement is recognizable by a reduction in the abdominal distension,
return of normal bowel sounds, and passage of flatus or stool. Repeat
1333abdominal radiographs should be obtained as necessary for further monitoring.
5. When the gastrointestinal tract function appears to have returned to
normal, the nasogastric tube may be removed and a liquid diet instituted.
If a patient shows no evidence of improvement during the first 48 to 72
hours of medical management, other causes of ileus should be sought. Such
cases may include ureteral injury, peritonitis from pelvic infection, unrecognized
gastrointestinal tract injury with peritoneal spill, or fluid and electrolyte
abnormalities such as hypokalemia. With persistent ileus, the use of water-soluble
upper gastrointestinal contrast studies (CT scan with oral contrast) may assist in
distinguishing an ileus from a small bowel obstruction. In the latter case, a
“transition point” is usually identified.
Small Bowel Obstruction
Obstruction of the small bowel following major, open gynecologic surgery
occurs in approximately 1% to 2% of patients (56,57). The most common
cause of small bowel obstruction is adhesions to the operative site. If the small
bowel becomes adherent in a twisted position, partial or complete obstruction
may result. Less common causes of postoperative small bowel obstruction include
entrapment of the small bowel into an incisional hernia or an unrecognized defect
in the small bowel or large bowel mesentery (internal hernia). [7] Early in its
clinical course, a postoperative small bowel obstruction may exhibit signs
and symptoms similar to those of ileus. Initial conservative management as
outlined for the treatment of ileus is appropriate. Because of the potential for
mesenteric vascular occlusion and resulting ischemia or perforation, worsening
symptoms of abdominal pain, progressive distension, fever, leukocytosis, or
acidosis should be evaluated carefully because immediate surgery may be
required.
In most cases of small bowel obstructions following gynecologic surgery, the
obstruction is only partial and the symptoms usually resolve with conservative
management.
1. Further evaluation after several days of conservative management may be
necessary. Evaluation of the small intestines with an upper gastrointestinal
study, or a CT scan with small bowel assessment is appropriate. In most cases,
complete obstruction is not documented, although a narrowing (“transition
point”) or tethering of the segment of small bowel may indicate the site of the
problem.
2. Laboratory evaluation should include CBC, serum electrolytes, and serum
lactate.
13343. Further conservative management with nasogastric decompression and
intravenous fluid and electrolyte replacement may allow time for bowel
wall edema or torsion of the mesentery to resolve.
4. Serial and radiographic examinations should be performed to exclude
possible bowel ischemia or perforation.
5. If resolution is prolonged and the patient’s nutritional status is marginal,
the use of TPN may be necessary.
6. Conservative medical management of postoperative small bowel
obstruction usually results in complete resolution. If persistent evidence of
small bowel obstruction remains after full evaluation and an adequate trial of
medical management, exploratory laparotomy may be necessary to manage the
obstruction. Risk factors for operative management include persistent
abdominal pain, distension, fever at 48 hours, and CT findings of high-grade
obstruction (58). In most cases, lysis of adhesions is all that is required,
although a segment of small bowel that is badly damaged or extensively
sclerosed from adhesions may require resection and reanastomosis.
Colonic Obstruction
Postoperative colonic obstruction following surgery for most gynecologic
conditions is exceedingly rare. It is usually associated with a pelvic malignancy,
which in most cases was known at the time of the initial operation. Advanced
ovarian carcinoma is the most common cause of colonic obstruction in
postoperative gynecologic surgery patients, and it is caused by extrinsic
impingement on the colon by the pelvic malignancy. Intrinsic colonic lesions may
be undetected, especially in a patient with some other benign gynecologic
condition. When colonic obstruction is manifested by abdominal distension and
abdominal radiography reveals a dilated colon and enlarging cecum, further
evaluation of the large bowel is required by water-soluble enema or colonoscopy.
Dilation of the cecum to more than 10 to 12 cm in diameter as viewed by
abdominal radiography requires immediate evaluation and surgical
decompression by performing colectomy or colostomy. Surgery should be
performed as soon as the obstruction is documented. Conservative management
of colonic obstruction is not appropriate because the complication of colonic
perforation has an exceedingly high mortality rate. In patients who are too ill to
undergo surgery, the interventional radiologist may be able to place a cecostomy
tube or the gastroenterologist may place a colonic stent (59).
Diarrhea
Episodes of diarrhea often occur following abdominal and pelvic surgery as the
gastrointestinal tract returns to its normal function and motility. Prolonged and
1335multiple episodes may represent a pathologic process such as impending small
bowel obstruction, colonic obstruction, or pseudomembranous colitis. Excessive
amounts of diarrhea should be evaluated by abdominal radiography and stool
samples tested for the presence of ova and parasites, bacterial culture, and C.
difficile toxin. Proctoscopy and colonoscopy may be advisable in severe cases.
Evidence of intestinal obstruction should be managed as outlined. Infectious
causes of diarrhea should be managed with the appropriate antibiotics and fluid
and electrolyte replacement. C. difficile–associated pseudomembranous colitis
may result from exposure to any antibiotic. Discontinuation of these antibiotics
(unless they are needed to treat another severe infection) is advisable, along with
the institution of appropriate therapy. Oral vancomycin is the preferred initial
treatment for severe C. difficile colitis (oral metronidazole is an alternative
treatment for moderate cases) (60).
Therapy should be continued until the diarrhea abates, and several weeks of
oral therapy may be required to obtain complete resolution of the
pseudomembranous colitis.
Fistula
Gastrointestinal fistulas are rare complications of gynecologic surgery. They are
most often associated with malignancy, prior radiation therapy, intestinal
resection with anastomosis, or surgical injury to the large or small bowel that was
improperly repaired or unrecognized. Signs and symptoms of gastrointestinal
fistula are often similar to those of small bowel obstruction or ileus, except that
fever is usually a more prominent component of the patient’s symptoms. When
fever is associated with gastrointestinal dysfunction postoperatively, evaluation
should include early assessment of the gastrointestinal tract to confirm its
continuity. When fistula is suspected, the use of water-soluble gastrointestinal
contrast material is advised to avoid the complication of barium peritonitis.
Evaluation with abdominal pelvic CT scan may assist in identification of a fistula
and associated abscess. Recognition of an intraperitoneal gastrointestinal leak
or fistula formation usually requires immediate surgery, unless the fistula
has drained spontaneously through the abdominal wall or vaginal cuff.
An enterocutaneous fistula arising from the small bowel and draining
spontaneously through the abdominal incision (with no evidence of
intraperitoneal infection) may be managed successfully with medical
therapy. Therapy should include nasogastric decompression, replacement of
intravenous fluids, TPN, and appropriate antibiotics to treat an associated mixed
bacterial infection. If the infection is under control and there are no other signs of
peritonitis, the surgeon may consider allowing potential resolution of the fistula
over a period of up to 2 weeks. Some authors suggested the use of somatostatin to
1336decrease intestinal tract secretion and allow earlier healing of the fistula. In some
cases, the fistula will close spontaneously with this mode of management. If the
enterocutaneous fistula does not close with conservative medical management,
surgical correction with resection, bypass, or reanastomosis will be necessary.
A rectovaginal fistula that occurs following gynecologic surgery is usually the
result of surgical trauma that may have been predisposed by the presence of
extensive adhesions and scarring in the rectovaginal septum associated with
endometriosis, pelvic inflammatory disease, or pelvic malignancy. A small
rectovaginal fistula may be managed with a conservative medical approach,
in the hope that decreasing the fecal stream will allow closure of the fistula. A
small fistula that allows continence except for an occasional leak of flatus may be
managed conservatively until the inflammatory process in the pelvis resolves. At
that point, usually several months later, correction of the fistula is appropriate.
Large rectovaginal fistulas for which there is no hope of spontaneous closure are
best managed by performing a diverting colostomy followed by repair of the
fistula after inflammation resolves. After the fistula closure is healed and deemed
successful, the colostomy may be reversed.
Thromboembolism
Risk Factors
[8] DVT and pulmonary embolism are largely preventable, yet significant,
complications in postoperative patients. The magnitude of this problem is
relevant to the gynecologist, because 40% of all deaths following gynecologic
surgery are directly attributed to pulmonary emboli, and it is the most
frequent cause of postoperative death in patients with uterine or cervical
carcinoma (61,62).
The causal factors of venous thrombosis were first proposed by Virchow in
1858 and include a hypercoagulable state, venous stasis, and vessel endothelial
injury. Risk factors include major surgery; advanced age; nonwhite race;
malignancy; history of DVT, lower extremity edema, or venous stasis changes;
presence of varicose veins; being overweight; a history of radiation therapy; and
hypercoagulable states, such as factor V Leiden, pregnancy, and use of oral
contraceptives, estrogens, or tamoxifen. Intraoperative factors associated with
postoperative DVT include increased anesthesia time, increased blood loss, and
the need for transfusion in the operating room. It is important to recognize these
risk factors and to provide the appropriate level of venous thrombosis prophylaxis
(63–66). Caprini has created a scoring system that attributes different “points” for
each risk factor that when totaled define a level of risk (67). The American
College of Chest Physicians (ACCP) has embraced the Caprini Risk Score to
1337define the recommended intensity of prophylaxis for an individual patient (68).
The levels of thromboembolism risk are listed in Table 25-7.
Prophylactic Methods
A number of prophylactic methods significantly reduced the incidence of DVT,
and a few studies included a large enough patient population to show a reduction
in fatal pulmonary emboli (69). The ideal prophylactic method would be
effective, free of significant side effects, well accepted by the patient and nursing
staff, widely applicable to most patients, and inexpensive.
Low-Dose Heparin
The use of small doses of subcutaneously administered heparin for the prevention
of DVT and pulmonary embolism is the most widely studied of all prophylactic
methods. More than 25 controlled trials demonstrated that heparin given
subcutaneously 2 hours preoperatively and every 8 to 12 hours
postoperatively is effective in reducing the incidence of DVT. The value of
low-dose heparin in preventing fatal pulmonary emboli was established by a
randomized, controlled multicenter international trial, which demonstrated a
significant reduction in fatal postoperative pulmonary emboli in general
surgery patients receiving low-dose heparin every 8 hours postoperatively
(69). Trials of low-dose heparin in gynecologic surgery patients showed a
significant reduction in postoperative DVT.
Although low-dose heparin is considered to have no measurable effect on
coagulation, most large series noted an increase in the bleeding complication rate,
especially a higher incidence of wound hematoma (70). Although relatively rare,
thrombocytopenia is associated with low-dose heparin use and was found in 6%
of patients after gynecologic surgery (70). If patients remain on low-dose heparin
for more than 4 days, it is reasonable to check their platelet count to assess the
possibility of heparin-induced thrombocytopenia.
Low–Molecular-Weight Heparin
Low–molecular-weight heparins (LMWH) are fragments of heparin that vary in
size from 4,500 to 6,500 Da. When compared with unfractionated heparin,
LMWH have more anti-Xa and less antithrombin activity, leading to less effect on
partial thromboplastin time and possibly leading to fewer bleeding complications
(71). An increased half-life of 4 hours results in increased bioavailability when
compared with unfractionated heparin. The increase in half-life of LMWH allows
the convenience of once-a-day dosing.
Table 25-7 Thromboembolism Risk Stratification (Caprini Risk Score)
13381 Point
Age 41–60 yrs
Minor surgery
BMI >25 kg/m2
Swollen legs
Varicose veins
Pregnancy or postpartum state
History of unexplained or recurrent abortions (>3)
Oral contraceptive use or hormone replacement
Sepsis (<1 mo)
Serious lung disease, including pneumonia (<1 mo)
Abnormal pulmonary function
Congestive heart failure
History of inflammatory bowel disease
Medical patient at bed rest
2 Points
Age 61–74 yrs
Major open surgery (>45 min)
Laparoscopic surgery (>45 min)
Malignancy
Confined to bed (>72 hrs)
Immobilizing cast
Central venous access
3 Points
Age >74 yrs
History of VTE
Family history of VTE
Congenital or acquired thrombophilias (i.e., Factor V Leiden, anticardiolipin antibodies,
elevated serum homocysteine, prothrombin 20210A)
Heparin-induced thrombocytopenia
5 Points
Stroke (<1 mo)
Elective arthroplasty
Hip, pelvis, or leg fracture
Acute spinal cord injury (<1 mo)
Randomized controlled trials have compared LMWH with unfractionated
heparin in patients undergoing gynecologic surgery. In all studies, there was
1339a similar incidence of DVT. Bleeding complications were similar between the
unfractionated heparin and LMWH groups (72). A meta-analysis of general
surgery and gynecologic surgery patients from 32 trials indicated that daily
LMWH administration is as effective as unfractionated heparin in DVT
prophylaxis without any difference in hemorrhagic complications (73).
Mechanical Methods
Stasis in the veins of the legs occurs while the patient is undergoing surgery and
continues postoperatively for varying lengths of time. Stasis occurring in the
capacitance veins of the calf during surgery, plus the hypercoagulable state
induced by surgery, are the prime factors contributing to the development of acute
postoperative DVT. Prospective studies of the natural history of postoperative
DVT showed that the calf veins are the predominant site of thrombi and that most
thrombi develop within 24 hours of surgery (74).
Although probably of only modest benefit, reduction of stasis by short
preoperative hospital stays and early postoperative ambulation should be
encouraged for all patients. Elevation of the foot of the bed, raising the calf above
heart level, allows gravity to drain the calf veins and should further reduce stasis.
Graduated Compression Stockings
Controlled studies of graduated compression stockings are limited but do suggest
modest benefit when they are carefully fitted (75,76). Poorly fitted stockings may
be hazardous to some patients who develop a tourniquet effect at the knee or midthigh (62). Variations in human anatomy do not allow perfect fit of all patients to
available stocking sizes. The simplicity of graduated compression stockings and
the absence of significant side effects are probably the two most important
reasons that they are often included in routine postoperative care. Compared to
thigh length stockings, calf-high stockings appear to offer the same degree of
venous thromboembolism protection (77).
Intermittent Pneumatic Compression
The largest body of literature dealing with the reduction of postoperative venous
stasis deals with intermittent compression of the leg by pneumatically inflated
sleeves placed around the calf or leg during intra- and postoperative periods. [8]
Various pneumatic compression devices and leg sleeve designs are available, and
the literature has not demonstrated superiority of one system over another. Calf
compression, during and after gynecologic surgery, significantly reduces the
incidence of DVT on a level similar to that of low-dose heparin. In addition to
increasing venous flow and pulsatile emptying of the calf veins, intermittent
pneumatic compression (IPC) appears to augment endogenous fibrinolysis, which
1340may result in lysis of very early thrombi before they become clinically significant
(78).
The duration of postoperative external pneumatic compression differed in
various trials. External pneumatic compression may be effective when used in the
operating room and for the first 24 hours postoperatively in patients at moderate
risk who will ambulate on the first postoperative day (78,79).
External pneumatic compression used in patients undergoing major
surgery for gynecologic malignancy reduced the incidence of postoperative
venous thromboembolic complications by nearly threefold, but only if calf
compression was applied intraoperatively and for the first 5 postoperative days
(80,81). Patients with gynecologic malignancies may remain at risk for a longer
period than general surgical patients because of stasis and hypercoagulable states;
therefore, these patients appear to benefit from longer use of IPC.
Table 25-8 VTE Prophylactic Regimens Based on an Individual’s Caprini Risk Score
Score
0: Early ambulation.
1–2: Low risk: Graded compression stockings and/or intermittent pneumatic
compression.
3–4: Moderate risk: Intermittent pneumatic compression or low-dose heparin or low–
molecular-weight heparin.
>4: High risk: Intermittent pneumatic compression and low-dose heparin or low–
molecular-weight heparin. Consider prolonged prophylaxis for 28 days.
Intermittent pneumatic leg compression has no significant side effects or risks
and is considered slightly more cost-effective when compared with
pharmacologic methods of prophylaxis (82). Compliance in wearing the leg
compression while in bed is of utmost importance, and the patient and nursing
staff should be educated to the proper regimen for maximum benefit (83).
[8] Using the Caprini Risk Score, the ACCP guidelines recommend different
prophylactic regimens based on an individual patient’s risk score (Table 25-8).
Continued prophylaxis for 28 days with low–molecular-weight heparin has
been shown to significantly reduce the incidence of VTE at 30 and 90 days
postoperatively in patients undergoing “open” abdominal procedures for
malignancy (84). There have been no trials specific to gynecologic surgery that
have evaluated prolonged prophylaxis, although this strategy seems reasonable,
especially for gynecologic cancer patients undergoing “open” procedures.
1341Guidelines do not distinguish the risks of minimally invasive gynecologic
surgery (MIGS) from “open surgery.” Some have argued that MIGSs are much
lower-risk surgical procedures and no prophylaxis is necessary (85). Others have
shown that despite the use of IPC, there remains approximately 2% incidence of
VTE in patients undergoing more complex gynecologic surgery (86).
Management of Postoperative Deep Venous Thrombosis and Pulmonary Embolism
Because pulmonary embolism is the leading cause of death following
gynecologic surgical procedures, identification of high-risk patients and the
use of prophylactic venous thromboembolism regimens are essential parts of
management (61,62,87).
The early recognition of DVT and pulmonary embolism and immediate
treatment are critical. Most pulmonary emboli arise from the deep venous
system of the leg following gynecologic surgery; the pelvic veins are also a
known source of fatal pulmonary emboli.
The signs and symptoms of DVT of the lower extremities include pain, edema,
erythema, and prominent vascular pattern of the superficial veins. These signs and
symptoms are relatively nonspecific; 50% to 80% of patients with these
symptoms will not have DVT (88). Conversely, approximately 80% of patients
with symptomatic pulmonary emboli have no signs or symptoms of thrombosis in
the lower extremities (89). Because of the lack of specificity when signs and
symptoms are recognized, additional tests should be performed to establish the
diagnosis of DVT.
Diagnosis
Doppler Ultrasound
B-mode duplex Doppler imaging is the most common technique for the
diagnosis of symptomatic venous thrombosis, especially when it arises in the
proximal lower extremity. With duplex Doppler imaging, the femoral vein can
be visualized and clots may be seen directly (90). Compression of the vein with
the ultrasound probe tip allows assessment of venous collapsibility; the presence
of a thrombus diminishes vein wall collapsibility. Doppler imaging is less
accurate when evaluating the calf and the pelvic veins.
Venography
Although venography is considered the “gold standard” technique for diagnosis of
DVT, other diagnostic studies are accurate when performed by a skilled
technologist and, in nearly all patients, may replace the need for contrast
venography. Venography is moderately uncomfortable, requires the intravenous
injection of a contrast material that may cause allergic reaction or renal injury,
1342and may result in phelebitis in approximately 1% of patients (91). If the results of
noninvasive imaging are normal or inconclusive and the clinician remains
concerned given clinical symptoms, venography should be performed to obtain a
definitive answer.
Magnetic Resonance Venography
In addition to having a sensitivity and specificity comparable to venography,
magnetic resonance venography (MRV) may detect thrombi in pelvic veins that
are not imaged by venography (92). The primary drawback to MRV is the time
involved in examining the lower extremity and pelvis and the expense of this
technology.
Treatment
Deep Venous Thrombosis
The treatment of postoperative DVT requires the immediate institution of
anticoagulant therapy. Treatment may be with either unfractionated heparin
or LMWH, followed by 3 to 6 months of oral anticoagulant therapy with
warfarin (Coumadin). The new oral antithrombins and factor Xa inhibitors are
options for secondary prophylaxis.
Unfractionated Heparin
After venous thromboembolism is diagnosed, unfractionated heparin (or low–
molecular-weight heparins, see below) should be initiated to prevent proximal
propagation of the thrombus and allow physiologic thrombolytic pathways to
dissolve the clot. An initial bolus of 80 U/kg is given intravenously, followed by a
continuous infusion of 1,000 to 2,000 U/hr (18 U/kg/hr). Heparin dosage is
adjusted to maintain APTT levels at a therapeutic level 1.5 to 2.5 times the
control value. Initial APTT should be measured after 6 hours of heparin
administration and the dose adjusted as necessary. Patients having subtherapeutic
APTT levels in the first 24 hours have a 15-fold increased risk of recurrent VTE
when compared to patients who are adequately anticoagulated. Patients should be
managed aggressively using intravenous heparin to achieve prompt
anticoagulation. A weight-based nomogram is helpful in achieving a therapeutic
APTT level (93).
Low–Molecular-Weight Heparin
Two LMWH preparations (enoxaparin and dalteparin) were effective in the
treatment of venous thromboembolism and have a cost-effective advantage
over intravenous heparin in that they may be administered in the outpatient
setting. The dosages used in treatment of thromboembolism are unique and
1343weight adjusted according to each LMWH preparation. Because LMWH has a
minimal effect on APTT, serial laboratory monitoring of these levels is not
necessary. Similarly, monitoring of anti-Xa activity (except in difficult cases or
those with renal impairment) is not of significant benefit in a dose adjustment of
LMWH. The increased bioavailability associated with LMWH allows for twice-aday dosing, potentially making outpatient management an option for a subset of
patients. A meta-analysis involving more than 4,000 patients from 22 trials
suggests that LMWH is more effective, safer, and less costly when compared
with unfractionated heparin in preventing recurrent thromboembolism (94).
Following initial treatment with either unfractionated heparin (UFH) or
LMWH, continued secondary prophylaxis/treatment is usually achieved by an
oral agent. In patients with active cancer, continued treatment with LMWH has
been found to be superior (95).
Oral anticoagulant (warfarin) administration may be started on the first
day of heparin infusion. The international normalized ration (INR) should be
monitored daily until a therapeutic level is achieved (2 to 3 times normal
value). The change in the INR resulting from warfarin administration often
precedes the anticoagulant effect by approximately 2 days, during which time
low-protein C levels are associated with a transient hypercoagulable state.
Therefore, heparin should be administered until the INR is maintained in a
therapeutic range for at least 2 days, confirming proper warfarin dose.
Intravenous heparin may be discontinued in 5 days if an adequate INR level is
established.
Oral inhibitors of thrombin or factor Xa may be used in place of warfarin
(96). Advantages of these agents include faster uptake and there is no need for
ongoing monitoring. Disadvantages include the fact that there is no agent to
“reverse” the anticoagulant effect (in the case of urgent surgery or bleeding), cost,
and the inconvenience of twice-a-day dosing (patient compliance). Safety and
efficacy in pregnancy have not been established. Therapeutic dosing of these
different agents is shown in Table 25-9.
Pulmonary Embolism
Many of the signs and symptoms of pulmonary embolism are associated with
other, more commonly occurring pulmonary complications following surgery.
The classic findings of pleuritic chest pain, hemoptysis, shortness of breath,
tachycardia, and tachypnea should alert the physician to the possibility of a
pulmonary embolism. Many times the signs are subtle and may be demonstrated
only by a persistent tachycardia or a slight elevation in the respiratory rate.
Patients suspected of pulmonary embolism should be evaluated initially by chest
x-ray, electrocardiography (ECG), and arterial blood gas assessment. Any
1344evidence of abnormality should be further evaluated by a spiral CT scan of the
chest or a ventilation–perfusion lung scan. A high percentage of lung scans may
be interpreted as “indeterminate.” In this setting, careful clinical evaluation and
judgment are required to decide whether pulmonary arteriography should be
performed to document or exclude the presence of a pulmonary embolism.
Table 25-9 Therapeutic Dosing of Non–Vitamin K Antagonist Oral Anticoagulants
Dosing—Typical initial doses in those with normal renal function are:
Rivaroxaban, 15 mg twice daily (for the first 3 weeks)
Apixaban, 10 mg twice daily (for first 7 days)
Edoxaban, 60 mg once daily (and 30 mg once daily in patients with a creatinine 30–
50 mL/min or a body weight below 60 kg)
Dabigatran, 150 mg twice daily
The treatment of pulmonary embolism is as follows:
1. Immediate anticoagulant therapy, identical to that outlined for the treatment of
DVT, should be initiated.
2. Respiratory support, including oxygen and bronchodilators, and an intensive
care setting, if necessary.
3. Although massive pulmonary emboli are usually quickly fatal, rarely
pulmonary embolectomy is successful.
4. Pulmonary artery catheterization (PAC) with the administration of
thrombolytic agents bears further evaluation and may be important in patients
with massive pulmonary embolism.
5. Vena cava interruption (filter) may be necessary in situations in which
anticoagulant therapy is ineffective in the prevention of rethrombosis and
repeated embolization from the lower extremities or pelvis. A vena cava filter
may be inserted percutaneously above the level of the thrombus and caudad to
the renal veins. In most cases, anticoagulant therapy is sufficient to prevent
repeat thrombosis and embolism and to allow the patient’s own endogenous
thrombolytic mechanisms to lyse the pulmonary embolus.
ENHANCED RECOVERY AFTER SURGERY (ERAS)
Rationale for ERAS
As surgical technology has been evolving, so have concepts for perioperative
1345care. Traditional perioperative management has included nothing by mouth (nil
per os, NPO) after midnight, liberal intraoperative fluids, and dependence on
opioid pain medications for postoperative pain. However, in the 1990s, European
physicians began to better understand the association between perioperative
physiologic stress and postoperative morbidity (97). Stress increases
immunosuppression, hypoxia, insulin resistance, and catabolism (98). An optimal
perioperative management strategy would target each of these factors to minimize
morbidity, and in the early 2000s, the initial enhanced recovery protocol was
crafted (99). ERAS was first embraced by colorectal physicians but has been
spreading throughout disciplines (100).
[6] Enhanced recovery protocols are comprehensive and address elements from
the patient’s initial arrival in the office with her chief complaint until she leaves
the hospital following surgery. Preoperatively, its components include
preoperative counseling, carbohydrate loading, the use of liberal antiemetics
(including preoperative steroids), and avoidance of prolonged fasting.
Intraoperatively, there is a focus on normothermia, balanced fluids, avoidance of
drains, a minimally invasive approach, multimodal pain medications, including
regional anesthesia when able. Following surgery, the aims include early
mobilization and feeding, prompt discontinuation of intravenous fluids,
multimodal pain medications, timely discontinuation of urinary catheters, and
regional anesthesia (99–101). Some important components of an ERAS protocol
will be highlighted below.
Perioperative Diet
With respect to perioperative nutrition, there are important considerations for an
ERAS protocol. There is no evidence regarding prolonged preoperative fasting
and aspiration risk (102), and fasting is known to increase insulin resistance
which increases perioperative morbidity. Given the paucity of data regarding
“NPO after midnight,” eating ad lib until 6 hours preoperatively followed by
consumption of clear liquids until 2 hours preoperatively is recommended by the
American Society of Anesthesiology (103). Another unique feature of an ERAS
protocol is preoperative carbohydrate loading. Drinks containing 12.5%
maltodextrin given 2 to 3 hours preoperatively have been shown to improve
insulin resistance and decrease hospital stay (104,105). Practically, the
recommendation is for the patient to ingest a 12-oz Gatorade 2 to 3 hours
preoperatively. Postoperatively the aim is early feeding, including for patients
who have undergone colorectal surgery, as there has not been an association in
increased anastomotic leak (106). With respect to postoperative fluids, the goal is
to discontinue as soon as possible or at the latest, on postoperative day 1.
1346Bowel Preparation
While some surgeons may recommend a bowel preparation preoperatively, there
has not been definitive evidence of benefit but there are areas of concern with
their use (107). Bowel preparations are implicated in patient dissatisfaction,
electrolyte disturbances, and dehydration. Therefore, ERAS protocols recommend
avoidance of bowel preparation.
Management of Nausea and Vomiting
Postoperative nausea and vomiting are unfortunately common in patients. A
multimodal, prophylactic approach utilizing medications in at least two antiemetic
classes has been employed. Available agents include NK-1 antagonists,
corticosteroids, 5-HT3 antagonists, butyrophenones, antihistamines,
phenothiazines, and anticholinergics (108). If nausea is present postoperatively,
an antiemetic of a different class should be used. A scopolamine patch can be
considered as it has been shown to improve postoperative nausea and vomiting
(109).
Perioperative Fluids
General Principles
Fluid and Electrolyte Maintenance Requirements
The body adjusts to higher and lower volumes of intake by changes in plasma
tonicity. Alterations in plasma tonicity induce adjustments in circulating
antidiuretic hormone (ADH) levels, which ultimately regulate the amount of
water retained in the distal tubule of the kidney. In the preoperative and the early
postoperative periods, it is usually necessary to replace only sodium and
potassium. Chloride is automatically replaced, concomitant with sodium and
potassium, because chloride is the usual anion used to balance sodium and
potassium in electrolyte solutions. There are various commercially available
solutions containing 40 mmol of sodium chloride, with smaller amounts of
potassium, calcium, and magnesium, designed to meet the requirements of a
patient who is receiving 3 L of intravenous fluids per day. The daily
requirement can be met by any combination of intravenous fluids. For
example, 2 L of D5 (5% dextrose)/0.45 normal saline (7 mEq sodium chloride
each), supplemented with 20 mEq of potassium chloride, followed by 1 L of
D5W (5% dextrose in water) with 20 mEq of potassium chloride, would
suffice.
Fluid and Electrolyte Replacement
1347Fluid and electrolyte losses beyond the daily average must be replaced by
appropriate solutions. The choice of solutions for replacement depends on the
composition of the fluids lost. Often, it is difficult to measure free water loss,
particularly in patients who have high losses from the lungs, skin, or the
gastrointestinal tract. Weighing these patients daily can be very useful. Up to 300
g of weight loss daily can be attributable to weight loss from catabolism of
protein and fat in the patient who is taking nothing by mouth (110). Any loss
beyond this level represents fluid loss, which should be replaced accordingly.
Patients with a high fever can have increased pulmonary and skin loss of
free water, sometimes in excess of 2 to 3 L per day. These losses should be
replaced with free water in the form of D5W. Perspiration typically has one-third
the osmolarity of plasma and can be replaced with D5W or, if the loss is
excessive, with D5/0.25 normal saline.
Patients with acute blood loss need replacement with appropriate isotonic
fluid or blood or both. There is a wide range of plasma volume expanders,
including albumin, dextran, and hetastarch solutions, that contain large molecularweight particles (<50 kDa molecular weight). These particles are slow to exit the
intravascular space, and about one-half of the particles remain after 24 hours.
Controversy exists over the ideal strategy for intravascular volume replacement
(111). A systematic review of 25 randomized clinical trials demonstrated
preserved renal function and reduced intestinal edema in surgical patients
receiving hyperoncotic albumin solutions, as compared with control fluids (112).
Meta-analyses on the use of human albumin and crystalloids versus colloids in
fluid resuscitation did not show a benefit in mortality rates (113,114). Caution is
required in interpreting results from these pooled controlled trials because
mortality outcome was not the end point of most of the studies, and publication
bias is a limitation. Possible side effects with synthetic colloid solutions include
adverse effects on hemostasis, severe anaphylactic reactions, and impairment of
renal function (111). These solutions are expensive and for most cases, simple
replacement with 0.9 normal saline or lactated Ringer solution will suffice.
One-third of the volume of lactated Ringer solution or normal saline typically will
remain in the intravascular space and the remainder goes to the interstitium.
Appropriate replacement of gastrointestinal fluid loss depends on the
source of fluid loss in the gastrointestinal tract. Gastrointestinal secretions
beyond the stomach and up to the colon are typically isotonic with plasma, with
similar amounts of sodium, slightly lower amounts of chloride, slightly alkaline
pH, and more potassium (in the range of 10 to 20 mEq/L). Under normal
conditions, stool is hypotonic. However, under conditions of increased flow (i.e.,
severe diarrhea), stool contents are isotonic with a composition similar to that of
the small bowel contents. Gastric contents are typically hypotonic, with one-third
1348the sodium of plasma, increased amounts of hydrogen ion, and low pH.
Postoperative Fluid and Electrolyte Management
Several hormonal and physiologic alterations in the postoperative period may
complicate fluid and electrolyte management. The stress of surgery induces an
inappropriately high level of circulating ADH. Circulating aldosterone levels are
increased, especially if sustained episodes of hypotension occurred either intra- or
postoperatively. The elevated levels of circulating ADH and aldosterone make
postoperative patients prone to sodium and water retention.
Total body fluid postoperative volume may be altered significantly. First, 1
mL of free water is released for each gram of fat or tissue that is catabolized and,
in the postoperative period, several hundred milliliters of free water are released
daily from tissue breakdown, particularly in the patient who has undergone
extensive intra-abdominal dissection and who is restricted from ingesting food
and fluids by mouth. This free water is often retained in response to the altered
levels of ADH and aldosterone. Second, fluid retention is further enhanced by
third spacing, or sequestration of fluid in the surgical field. The development of
an ileus may result in an additional 1 to 3 L of fluid per day being
sequestered in the bowel lumen, bowel wall, and peritoneal cavity.
In contrast to renal sodium homeostasis, the kidney lacks the capacity for
retention of potassium. In the postoperative period, the kidneys continue to
excrete a minimum of 30 to 60 mEq/L of potassium daily, irrespective of the
serum potassium level and total body potassium stores (115). If this potassium
is not replaced, hypokalemia may develop. Tissue damage and catabolism during
the first postoperative day usually result in the release of sufficient intracellular
potassium to meet the daily requirements. Beyond the first postoperative day,
potassium supplementation is necessary.
Correct maintenance of fluid and electrolyte balance in the postoperative
period starts with the preoperative assessment, with emphasis on establishing
normal fluid and electrolyte parameters before surgery. Postoperatively, close
monitoring of daily weight, urine output, serum hematocrit, serum electrolytes,
and hemodynamic parameters will yield the necessary information to make
correct adjustments in crystalloid replacement. The normal daily fluid and
electrolyte requirements must be met and any unusual fluid and electrolyte losses,
including those from the gastrointestinal tract, lungs, or skin, must be
compensated. After the first few postoperative days, third-space fluid begins to
return to the intravascular space, and ADH and aldosterone levels revert to
normal. The excess fluid retained perioperatively is mobilized and excreted
through the kidneys, and exogenous fluid requirements decrease. Patients with
inadequate cardiovascular or renal reserve are prone to fluid overload during this
1349time of third-space reabsorption, especially if intravenous fluids are not
appropriately reduced.
The most common fluid and electrolyte disorder in the postoperative
period is fluid overload. Fluid excess can occur concomitantly with normal or
decreased serum sodium. Large amounts of isotonic fluids are usually infused
intraoperatively and postoperatively to maintain blood pressure and urine output.
Because the infused fluid is often isotonic with plasma, it will remain in the
extracellular space. Under such conditions, serum sodium will remain within
normal levels. Fluid excess with hypotonicity (decreased serum sodium) can
occur if large amounts of isotonic fluid losses (e.g., blood and gastrointestinal
tract) are inappropriately replaced with hypotonic fluids. The predisposition
toward retention of free water in the immediate postoperative period compounds
the problem. An increase in body weight occurs concomitantly with the fluid
expansion. In the patient who is not allowed anything by mouth, catabolism
should induce a daily weight loss as great as 300 g per day. The patient who is
gaining weight in excess of 150 g per day is in a state of fluid expansion. Simple
fluid restriction will correct the abnormality. When necessary, diuretics can be
used to increase urinary excretion.
States of fluid dehydration are uncommon but will occur in patients who have
large daily losses of fluid that are not replaced. Gastrointestinal losses should be
replaced with the appropriate fluids. Patients with high fevers should be
given appropriate free water replacement, because up to 2 L per day of free
water can be lost through perspiration and hyperventilation. Although these
increased losses are difficult to monitor, a reliable estimate can be obtained by
monitoring body weight.
Tenets of Fluid Management in ERAS
[3] The ideal fluid management for a perioperative patient is euvolemia. In order
to achieve this, ERAS protocols consist of minimizing crystalloids and
prioritizing the use of colloids and vasopressors when needed. When crystalloids
are used, balanced fluids (such as lactated Ringers) are preferred. Many times this
approach is goal-oriented, utilizing measurements of stroke volume to guide
resuscitation. There is evidence that patients have improved postoperative
outcomes when utilizing either hypovolemic or goal-oriented fluid paradigms
(116).
Postoperative Pain Management
General Principles
[4] Although satisfactory analgesia is easily achievable with available
1350methods, patients continue to suffer unnecessarily from postoperative pain.
Studies consistently show that 25% to 50% of patients suffer moderate to
severe pain in the postoperative period (117,118). There are several reasons for
the existing inadequacies in pain management. First, patient expectations of pain
relief are low and they are not aware of the extent of analgesia that they should
expect. Second, there is a lack of formal physician training in pain management.
Third, attitudes continue to be influenced by the common misconception that the
use of narcotics in the postoperative period results in opioid dependence.
Many effective pain control paradigms exist. The patient-controlled
analgesia (PCA) technique, which allows patients to self-administer small
doses of narcotic on demand, allows titration of measured boluses of narcotic
as needed to relieve pain. This technique can provide a more thorough
analgesia with maintenance of steady-state drug concentrations. These
devices eliminate the delay between the onset of pain and the administration
of analgesic agents, a common problem inherent with on-demand analgesic
orders in busy hospital wards. PCA has excellent patient acceptance. Compared
with conventional intramuscular injections, serum narcotic levels have
significantly lower variability in patients using PCA (119). Patients using PCA
have improved analgesia, a lower incidence of postoperative pulmonary
complications, and less confusion than those given intramuscular narcotics (120).
The total dose of narcotic used is lower with PCA than with conventional
intramuscular depot injection.
The use of PCA does not eliminate the adverse side effects of narcotics.
Potentially life-threatening respiratory depression is seen in as many as 0.5% of
patients using PCA. The use of a continuous narcotic infusion in addition to
demand dosing is associated with a fourfold increase in respiratory depression.
Elderly patients and those with pre-existing respiratory compromise are at risk for
respiratory depression (119).
In summary, use of PCA shortens the time between the onset of pain and
the administration of pain medication, provides more continuous access to
analgesics, and permits an overall steadier state of pain control.
Epidural and Spinal Analgesia
Anesthetics and narcotics administered either in the epidural space or
intrathecally are among the most potent analgesic agents available; the efficacy of
these agents is greater than that provided by intravenous PCA techniques. These
drugs can be administered in several ways, including a single-shot dose given by
epidural or intrathecal injection, intermittent injection given either on schedule or
on demand, and continuous infusion.
Because of the risk of central nervous system infections and headaches,
1351intrathecal administration is usually limited to a single dose of narcotic, local
anesthetic, or both. In comparison with epidural administration, duration of action
for a single dose is increased via the intrathecal route as a result of the high
concentrations of drug attained in the cerebrospinal fluid. The risk of central
nervous system and respiratory depression, and systemic hypotension, is
increased. The low doses of opioids required for intrathecal analgesia are
sufficient to be associated with an increased risk of respiratory depression (121).
Some investigators warn against the use of intrathecal spinal analgesia outside the
intensive care setting.
Epidural administration is the preferred approach and provides extended
(>24 hours) pain control during the postoperative period. Relative
contraindications are the presence of coagulopathy, sepsis, and hypotension. Both
anesthetic and narcotic agents are used with excellent efficacy. Among the
anesthetic agents, bupivacaine is the most popular, providing excellent analgesia
with minimal toxicity. Epidural analgesia is most suited for pain control in the
lower abdomen and extremities. Potential adverse effects of epidural anesthetic
agents include urinary retention, motor weakness, hypotension, and central
nervous system and cardiac depression. In contrast to anesthetic agents, opioids
offer excellent analgesia without accompanying sympathetic blockade. Epidural
opioids tend to have a much longer duration of action, and hypotension is a rare
complication. Compared with epidural anesthetics, there is a higher incidence of
nausea and vomiting, respiratory depression, and pruritus (122).
Compared with analgesics administered intramuscularly or intravenously,
epidural analgesia is associated with improved postoperative pulmonary function,
a lower incidence of pulmonary complications, a decrease in postoperative venous
thromboembolic complications (most likely secondary to earlier ambulation),
fewer gastrointestinal side effects, a lower incidence of central nervous system
depression, and shorter convalescence (122). A systematic review concluded
that continuous epidural anesthesia is more effective than intravenous opioid
PCA in reducing postoperative pain for up to 72 hours after abdominal
surgery (123). Severe respiratory depression, which occurs in less than 1% of
patients, is the most serious potential complication. A lower incidence of
respiratory depression occurs with the more lipophilic drugs such as fentanyl,
which is quickly absorbed within the spinal cord and is less likely to diffuse to the
central nervous system respiratory control centers. Pruritus, nausea, and urinary
retention are common but can be managed easily and usually are of little clinical
significance. Cost is perhaps the main and most limiting drawback of epidural
analgesia.
Close monitoring by nursing staff is required for safe administration of
epidural analgesia. An intensive care setting is not necessary. Epidural
1352analgesics can be administered safely in a hospital ward setting under close
nursing supervision, using respiratory monitoring with hourly ventilatory checks
during the first 8 hours of epidural analgesia.
Nonsteroidal Anti-Inflammatory Drugs
Current therapeutic strategies for perioperative pain control are largely dependent
on multimodal therapy with opioid analgesics and nonsteroidal anti-inflammatory
drugs (NSAIDs). The nonselective NSAID ketorolac is a potent drug that can be
given orally or parenterally. Ketorolac has a slightly slower onset of activity
than fentanyl but has an analgesic potency comparable to morphine. The
theoretical advantages of NSAIDs over opioids include absence of respiratory
depression, lack of abuse potential, decreased sedative effects, decreased nausea,
early return of bowel function, and faster recovery. In clinical studies, ketorolac is
found to have analgesic effects similar to those of morphine in postoperative
orthopedic patients and, when used in conjunction with PCA, significantly
reduced opioid requirements (124,125). Depending on the type of surgery,
ketorolac has an opioid dose-sparing effect of a mean of 36% and improves
analgesic control of moderate to severe pain 24 hours postoperatively (126). In
the obstetric population, intravenous ketorolac is effective in reducing
postoperative narcotic use after cesarean delivery (127). Although the U.S. Food
and Drug Administration has not approved ketorolac for use during lactation, it
was quantified in breast milk and has lower levels than ibuprofen (128).
Potential adverse effects associated with the use of NSAIDs include an
increased risk of renal compromise (particularly in patients suffering from acute
hypovolemia), gastrointestinal side effects, hypersensitivity reactions, and
bleeding. The effects of ketorolac on bleeding are inconsistent. Studies of
ketorolac on healthy volunteers showed transient increases in bleeding time and
decreases in platelet aggregation, but these changes were not clinically significant
(129). A retrospective cohort study showed increased risk of gastrointestinal and
operative site bleeding in elderly patients receiving high doses of ketorolac,
between 105 and 120 mg per day. Increased risk for all gastrointestinal bleeding
was associated with the use of ketorolac for more than 5 days (130). Controlled
prospective studies did not show a significant increase in blood loss in patients
who receive NSAIDs perioperatively. Ketorolac may be associated with elevated
rates of acute renal failure when therapy exceeds 5 days (131). A meta-analysis of
the use of postoperative NSAIDs in patients with normal preoperative renal
function showed a clinically insignificant reduction in renal function (132). These
agents should be used with extreme care, if at all, in patients with asthma, because
5% to 10% of adult patients with asthma are sensitive to aspirin and other NSAID
preparations.
1353With the advantages of less gastrointestinal toxicity and a lack of antiplatelet
effects, selective cyclooxygenase-2 (COX-2) inhibitors are a valuable option in
perioperative pain management (133). Although evidence exists showing an
increased risk of serious cardiovascular events associated with COX-2 inhibitors,
short-term use of these agents in the perioperative setting can be considered in
low-risk patients without existing cardiovascular disease (134–139).
In addition to NSAIDs, other adjuvant analgesics are being explored to
minimize opioid use and the accompanying side effects, which can delay
recovery. Capsaicin is a nonnarcotic that promotes release of substance P, a
neurotransmitter for pain and heat, which initially results in a burning sensation,
but eventually leads to substance P depletion and a reduction in pain. It is
available in topical and injectable preparations. Ketamine blocks centrally located
N-methyl-d-aspartate pain receptors, and at low subanesthetic doses can reduce
central sensitization caused by surgery and prevent opioid-induced hyperalgesia.
At higher doses, ketamine is associated with hallucinations, dizziness, nausea, and
vomiting. Gabapentin and pregabalin are nonnarcotics that prevent the release of
excitatory neurotransmitters that relay pain signals. They reduce opioid
requirements and are effective antihyperalgesic agents (139).
Tenets of Pain Control in ERAS
Postoperative pain control is an important focus of ERAS protocols. Opioids are
implicated in slowing gastrointestinal function, increasing nausea and vomiting,
and at times creating patient confusion. All of these factors directly inhibit
postoperative progress. Therefore, a successful pain medication approach needs to
be multimodal and not primarily rely on opioids. ERAS protocols include
preoperative medications which often include NSAIDs, GABA agonists, and/or
muscle relaxants. Many protocols include the use of regional anesthesia for pain
control, especially in the context of a laparotomy. With the use of an epidural,
postoperative pain control and gastrointestinal function have been found to be
improved versus the use of an opioid PCA (140). The use of epidural analgesia
has been associated with difficulty ambulating and urinary retention, which goes
against the goals of an ERAS protocol (141). After incision closure, use of local
bupivacaine is encouraged. Other important postoperative pain medications
include the use of NSAIDs (i.e., ketorolac).
Drains
Prophylactic drains have been used since the 1800s in an effort to reduce
perioperative fluid collections or identify bleeding or anastomotic leaks. Studies
have found that drains provide low sensitivity in detecting a leak (142). There is
1354limited data regarding prophylactic drain use in pelvic surgery and data is
inconsistent. Routine use of prophylactic drains is not recommended, but can be
considered in the setting of patient risk factors.
Similarly, nasogastric tubes had commonly been utilized in the postoperative
period in order to protect anastomoses. Studies have found no clear benefit of
prophylactic nasogastric tube use. A meta-analysis of approximately 5,000
patients revealed that patients without nasogastric tubes demonstrated less time to
bowel function and a shorter hospital stay. The rate of anastomotic leak was no
different between the two groups (143). Routine nasogastric tube use is
discouraged.
Laxatives
To encourage expeditious return of bowel function, laxatives are often used.
While available data does not demonstrate a clear benefit, there are few if any
adverse effects with their use. Therefore, laxatives may be used in the
postoperative period.
Outcomes of ERAS Protocols
[5] Given the purposeful design of enhanced recovery protocols, outcomes have
demonstrated significant improvement in many areas of perioperative care. In
meta-analyses, ERAS protocols have been associated with an average decrease in
length of hospital stay of 1.14 days without a concomitant increase in readmission
(144). Similarly, complication rates were decreased by half (145). Studies have
shown that as compliance to a protocol increases, mortality decreases (146).
Fitting with decreased perioperative complications and reduced readmissions,
Canadian ERAS protocols have been associated with health care cost savings up
to $7,000 per patient (147). Another benefit of an ERAS protocol is that patients
report improved quality of life and decreased pain scores (148,149).
A challenge of enhanced recovery protocols is the need for a highly dynamic
and cooperative atmosphere as teamwork and standardization are crucial to the
success of such a protocol (141). This includes the patient herself, the surgeon,
the anesthesiologist, and the nurses, dietitians, trainees, and hospital
administrators. While this is not an easy undertaking, it is of utmost importance,
given the broad benefits seen in perioperative care with initiation of and
adherence to an enhanced recovery protocol.
MANAGEMENT OF MEDICAL PROBLEMS
Correction of Existing Fluid and Electrolyte Abnormalities
1355Correct maintenance of fluid and electrolyte balance in the postoperative
period starts with the preoperative assessment, with emphasis on establishing
normal fluid and electrolyte parameters before surgery. Preoperative
electrolyte abnormalities can pose a diagnostic challenge. The correct diagnosis
and therapy are contingent on a correct assessment of total body fluid and
electrolyte status. After taking a detailed history, initial evaluation should include
an assessment of hemodynamic, clinical, and urinary parameters to determine the
overall level of hydration and the fluid status of the extracellular fluid
compartment. The patient with good skin turgor, moist mucosa, stable vital signs,
and good urinary output is well hydrated. The patient with orthostasis, sunken
eyes, parched mouth, and decreased skin turgor has extracellular volume
contraction.
The laboratory workup for patients with pre-existing fluid problems
should include assessment of blood hematocrit, serum chemistry, glucose,
BUN and creatinine, urine osmolarity, and urine electrolyte levels. Serum
osmolarity is calculated by the following equation:
2[Na+] + glucose (mg/dL)/18 + BUN (mg/dL)/2.8
Normal serum osmolarity is typically 290 to 300 mOsm. The
BUN:creatinine ratio is typically 10:1 but will rise to a ratio of greater than
20:1 under conditions of extracellular fluid contraction. Under conditions of
extracellular fluid deficit, urine osmolarity will typically be high (>400
mOsm), whereas urine sodium concentration is low (<15 mEq/L), indicative
of an attempt by the kidney to conserve sodium. Under conditions of
extracellular fluid excess or in cases of renal disease, in which the kidney has
impaired ability to retain sodium and water, urine osmolarity will be low and
urine sodium will be high (>30 mEq/L).
Specific Electrolyte Disorders
Hyponatremia
Because sodium is the major extracellular cation, shifts in serum sodium
levels are usually inversely correlated with the hydration state of the
extracellular fluid compartment. The pathophysiology of hyponatremia is
usually expansion of body fluids leading to excess total body water (115,150).
Symptomatic hyponatremia usually does not occur until the serum sodium is
below 120 to 125 mEq/L. The severity of the symptoms (nausea, vomiting,
lethargy, seizures) is related more to the rate of change of serum sodium than to
the actual serum sodium level.
Hyponatremia secondary to inappropriate secretion of ADH can occur with
1356head trauma, pulmonary or cerebral tumors, and states of stress. The abnormally
elevated ADH results in excess water retention. Treatment includes water
restriction and, if possible, correction of the underlying cause. Hyponatremia in
the form of extracellular fluid excess can be seen in patients with renal or cardiac
failure and in conditions such as nephrotic syndrome, in which total body salt and
water are increased, with a relatively greater increase in the latter. Administration
of hypertonic saline to correct the hyponatremia would be inappropriate in this
setting. In addition to correcting the underlying disease process, treatment should
include, water restriction with diuretic therapy.
Inappropriate replacement of body salt losses with water alone will result
in hyponatremia. This situation will typically occur in patients who lose large
amounts of electrolytes secondary to vomiting, nasogastric suction, diarrhea, or
gastrointestinal fistulas, and who received replacement with hypotonic solutions.
Simple replacement with isotonic fluids and potassium will usually correct the
abnormality. Rarely, rapid correction of the hyponatremia is necessary, in which
case hypertonic saline (3%) can be administered. Hypertonic saline should be
administered very cautiously to avoid a rapid shift in serum sodium, which will
induce central nervous system dysfunction.
Hypernatremia
Hypernatremia is an uncommon condition that can be life-threatening if
severe (serum sodium greater than 160 mEq/L). Extracellular fluid deficit
results in a hyperosmolar state, which can cause disorientation, seizures,
intracranial bleeding, and death. The causes include excessive extrarenal water
loss, which can occur in patients who have a high fever, who have diabetes
insipidus, either central or nephrogenic, and who have iatrogenic salt loading. The
treatment involves correction of the underlying cause and replacement with free
water either by the oral route or intravenously with D5W. As with severe
hyponatremia, marked hypernatremia should be corrected slowly, no faster than
10 mEq per day, unless the patient is symptomatic from severe acute
hypernatremia (151).
Hypokalemia
Hypokalemia may be encountered preoperatively in patients with significant
gastrointestinal fluid loss (prolonged emesis, diarrhea, nasogastric suction,
intestinal fistulas) or marked urinary potassium loss secondary to renal
tubular disorders (renal tubular acidosis, acute tubular necrosis,
hyperaldosteronism, prolonged diuretic use). The symptoms associated with
hypokalemia include neuromuscular disturbances, ranging from muscle weakness
to flaccid paralysis, and cardiovascular abnormalities, including hypotension,
1357bradycardia, arrhythmias, and enhancement of digitalis toxicity. These symptoms
rarely occur unless the serum potassium level is less than 3 mEq/L. The treatment
is potassium replacement. Oral therapy is preferable in patients who are on an oral
diet. If necessary, potassium replacement can be given intravenously in doses that
should not exceed 10 mEq per hour.
Hyperkalemia
Hyperkalemia is encountered infrequently in preoperative patients. It is
usually associated with renal impairment, adrenal insufficiency, or
potassium-sparing diuretic use. Marked hyperkalemia (potassium >7 mEq/L)
can result in bradycardia, ventricular fibrillation, and cardiac arrest. The treatment
chosen depends on the severity of the hyperkalemia and whether there are
associated cardiac abnormalities detected with ECG. Calcium gluconate (10 mL
of a 10% solution), given intravenously, can quickly offset the toxic effects of
hyperkalemia on the heart. One ampule each of sodium bicarbonate and D5W,
with or without insulin, will cause a rapid shift of potassium into cells. Over the
longer term, cation exchange resins such as sodium polystyrene sulfate
(Kayexalate), taken orally or by enema, will bind and decrease total body
potassium. Hemodialysis is reserved for emergent conditions in which other
measures are not sufficient or have failed (151).
Postoperative Fluid and Electrolyte Management
Several hormonal and physiologic alterations in the postoperative period may
complicate fluid and electrolyte management. The stress of surgery induces an
inappropriately high level of circulating ADH and aldosterone levels, making
postoperative patients prone to sodium and water retention.
Total body fluid postoperative volume may be altered significantly. First,
free water is released from tissues postoperatively, particularly in the patient who
has undergone extensive intra-abdominal dissection and who is restricted from
oral hydration. This free water is often retained in response to the elevated levels
of ADH and aldosterone. Second, fluid retention is further enhanced by third
spacing of fluid in the surgical field. The development of an ileus may result in
an additional 1 to 3 L of fluid per day being sequestered in the bowel lumen,
bowel wall, and peritoneal cavity. After the first few postoperative days, thirdspace fluid begins to return to the intravascular space, and ADH and aldosterone
levels revert to normal. The excess fluid retained perioperatively is mobilized and
excreted through the kidneys, and exogenous fluid requirements decrease.
In contrast to renal sodium homeostasis, the kidney lacks the capacity for
retention of potassium. In the postoperative period, the kidneys continue to
excrete a minimum of 30 to 60 mEq/L of potassium daily, irrespective of the
1358serum potassium level and total body potassium stores (115). If this potassium
is not replaced, hypokalemia may develop. Tissue damage and catabolism during
the first postoperative day usually result in the release of sufficient intracellular
potassium to meet the daily requirements. Beyond the first postoperative day,
potassium supplementation is necessary.
Patients with inadequate cardiovascular or renal reserve are prone to fluid
overload during this time of third-space reabsorption, especially if intravenous
fluids are not appropriately reduced.
The most common fluid and electrolyte disorder in the postoperative
period is fluid overload. An increase in body weight occurs concomitantly with
the fluid expansion. The patient who is gaining weight in excess of 150 g per day
is in a state of fluid expansion. Simple fluid restriction will correct the
abnormality. Diuretics can be used to increase urinary excretion, where
appropriate.
States of fluid dehydration are uncommon but will occur in patients who have
large daily losses of fluid that are not replaced. Gastrointestinal losses should be
replaced with the appropriate fluids. Patients with high fevers should be
given appropriate free water replacement, because up to 2 L per day of free
water can be lost through perspiration and hyperventilation. Although these
increased losses are difficult to monitor, a reliable estimate can be obtained by
monitoring body weight.
Postoperative Acid–Base Disorders
A variety of metabolic, respiratory, and electrolyte abnormalities in the
postoperative period can result in an imbalance in normal acid–base homeostasis,
leading to alkalosis or acidosis. Proper fluid and electrolyte replacement and
maintenance of adequate tissue perfusion will help prevent or correct most acid–
base disorders that occur during the postoperative period.
Alkalosis
The most common acid–base disorder encountered in the postoperative
period is alkalosis (115). Alkalosis is usually of no clinical significance and
resolves spontaneously. While respiratory alkalosis usually results from
hyperventilation caused by excitation of the central nervous system, numerous
metabolic derangements can result in metabolic alkalosis, including posttraumatic
transient hyperaldosteronism, nasogastric suction, infusion of bicarbonate during
blood transfusions in the form of citrate, and use of diuretics. Alkalosis can be
corrected with removal of the inciting cause and the correction of extracellular
fluid and potassium deficits (Table 25-10). Full correction usually can be safely
achieved over 1 to 2 days.
1359Marked alkalosis (serum pH >7.55) can result in serious cardiac
arrhythmias or central nervous system seizures. Myocardial excitability is
particularly pronounced with concurrent hypokalemia. Under such conditions,
fluid and electrolyte replacement may not be sufficient to rapidly correct the
alkalosis, requiring treatment with acetazolamide or an acidifying agent.
Table 25-10 Causes of Metabolic Alkalosis
Disorder Source of Alkali Cause of Renal HCO
Retention
Gastric alkalosis
Nasogastric suction Gastric mucosa ↓↓ ECF, ↓ K
Vomiting
Renal alkalosis
Diuretics Renal epithelium ↓ ECF, ↓ K
Respiratory acidosis and
diuretics
↓ ECF, ↓ K, ↑ PCO2
Exogenous base NaHCO3, Na citrate, Na
lactate
Coexisting disorder of ECF, K,
PaCO2
↓ ECF, extracellular fluid depletion; ↓ K, potassium depletion; ↑↑ PCO2, carbon dioxide
retention; NaHCO3, sodium bicarbonate; PaCO2, partial pressure of carbon dioxide,
arterial.
Acidosis
Respiratory acidosis results from carbon dioxide retention in patients who
have hypoventilation. Metabolic acidosis is less common during the
postoperative period but can be serious because of its effect on the
cardiovascular system, including decreased myocardial contractility, a
propensity for hypotension, and refractoriness of the fibrillating heart to
defibrillation (115).
Metabolic acidosis results from a decrease in serum bicarbonate levels. The
proper workup includes a measurement of the anion gap:
Anion gap = (Na+ + K+) − (Cl− + HCO3−) = 10 to 14 mEq/L (normal)
The anion gap is composed of circulating protein, sulfate, phosphate, citrate,
1360and lactate.
With metabolic acidosis, the anion gap can be increased or normal. An
increase in circulating acids will consume and replace bicarbonate ion, increasing
the anion gap. Postoperatively, conditions of poor tissue perfusion will increase
circulating lactic acid, severe diabetes or starvation will increase ketoacids, and
renal dysfunction will increase circulating sulfates and phosphates (152). The
diagnosis can be established via a thorough history and measurement of serum
lactate (normal <2 mmol/L), serum glucose, and renal function parameters.
Metabolic acidosis in the face of a normal anion gap is usually the result of excess
chloride and decreased bicarbonate that can be seen in patients who underwent
saline loading, those with severe diarrhea or renal tubular acidosis. A summary of
the various causes of metabolic acidosis is shown in Table 25-11.
The treatment of metabolic acidosis depends on the cause. In patients with
lactic acidosis, restoration of tissue perfusion is imperative. This state can be
accomplished through cardiovascular and pulmonary support as needed, oxygen
therapy, and aggressive treatment of systemic infection wherever appropriate.
Ketosis from diabetes can be corrected gradually with insulin therapy. Ketosis
resulting from chronic starvation or from lack of caloric support postoperatively
can be corrected with nutrition. In patients with normal anion gap acidosis,
bicarbonate lost from the gastrointestinal tract should be replaced, excess chloride
administration can be curtailed, and, where necessary, a loop diuretic can be used
to induce renal clearance of chloride. Dilutional acidosis can be corrected with
mild fluid restriction.
Table 25-11 Causes of Metabolic Acidosis
High Anion Gap Normal Anion Gap
Hyperkalemic Hypokalemic
Uremia Hyporeninism Diarrhea
Ketoacidosis Primary adrenal failure Renal tubular acidosis
Lactic acidosis NH2Cl Ileal and sigmoid bladders
Aspirin Sulfur poisoning Hyperalimentation
Paraldehyde Early chronic renal failure
Methanol Obstructive uropathy
Ethylene glycol
1361Methylmalonic aciduria
NH2Cl (chloramine)
Adapted from Narins RG, Lazarus MJ. Renal system. In: Vandam LD, ed. To Make the
Patient Ready for Anesthesia: Medical Care of the Surgical Patient. 2nd ed. Menlo Park,
CA: Addison Wesley; 1984:67–114.
Bicarbonates should not be given unless serum pH is lower than 7.2 or
severe cardiac complications secondary to acidosis are present. Close
monitoring of serum potassium levels is mandatory. Under states of acidosis,
potassium will exit the cell and enter the circulation. The patient with a normal
potassium concentration and metabolic acidosis is actually depleted of
intracellular potassium. Treatment of the acidosis without potassium replacement
will result in severe hypokalemia with its associated risks.
Endocrine Disease
The three most frequent endocrine disorders that occur in patients undergoing
gynecologic surgery are diabetes mellitus (DM), thyroid disease, and adrenal
abnormalities. The pathophysiology of these disorders aids in understanding the
effects of surgery on patients with these problems.
Diabetes Mellitus
DM is a complicated medical disorder of glucose metabolism that is related to a
lack of production of, or resistance to, insulin. According to the American
Diabetes Association, 14.9 million American women, or 11.7% of all women
older than 18 years, suffer from diabetes (153). Approximately 50% of
individuals with DM will require surgery during their lives (154). The direct
effect of DM on the end organs determines the risk of surgery, rather than the
type or duration of surgery or the management of the condition itself. The current
criteria for diagnosis of diabetes include (155):
1. Polyuria, polydipsia, or unexplained weight loss with a random nonfasting
glucose of ≥200 mg/dL, or
2. Fasting glucose ≥126 mg/dL (in which fasting is defined as no food intake for
8 hours), or
3. Two-hour oral glucose tolerance test of 75 g, with serum glucose ≥200 mg/dL,
or
4. Hemoglobin A1c ≥6.5%.
1362Confirmation of the diagnosis requires repeating the same test on a different
day or concordant results of two different tests simultaneously.
Patients with DM have elevated risk of coronary artery disease and
experience exaggerated hyperglycemia perioperatively. With this in mind,
goals of the preoperative assessment and perioperative management are to ensure
glycemic control and metabolic homeostasis and to anticipate complications
related to DM.
Preoperative Risk Assessment
Preoperative risk assessment for diabetes should begin with a review of systems.
Nocturia, polyuria, polydipsia, glucosuria, obesity, previous gestational diabetes,
ethnicity, and family history are relevant aspects of the history.
Type 1 (insulin-dependent) diabetes, or type 2 diabetes (noninsulin-dependent),
should be established because the preoperative risk and perioperative
management of each differs. The patient’s routine glucose management strategies,
glucose levels, medications, and baseline hemoglobin A1c should be assessed
(156). The presence of end-organ complications of diabetes should be
documented.
Cardiovascular risk resulting from large- and small-vessel arterial
occlusive disease should be a focus in the preoperative setting. A careful
history and physical examination should be performed to determine the presence
or absence of coronary artery or cerebral vascular disease (154). Diabetic patients
are less likely to have symptoms of coronary disease compared to their
nondiabetic counterparts. For patients with inducible ischemia, coronary artery
disease, or multiple clinical risk factors for heart disease, perioperative β-
blockade should be considered, with initiation and careful titration of medication
several weeks prior to surgery (157,158). Further evidence of end-organ disease
can manifest as retinal or renal dysfunction. If diabetic nephropathy is present,
imaging studies using contrast dye should be avoided. If a contrast study must be
performed, adequate hydration before and after the procedure is essential, and oral
metformin should be withheld for 24 to 48 hours after the procedure.
Diabetes is associated with increased perioperative infections (159).
Preoperative evaluation should include examination of the skin and urine
sediment to detect asymptomatic infection. Wound infections, skin infections,
pneumonia, and urinary tract infections account for two-thirds of the
postoperative complications in patients with diabetes (160). There is a known
predisposition for patients with DM to have increased colonization by methicillinresistant Staphylococcus aureus, increased infections by gram-negative and
staphylococcal bacteria, and an increased incidence of gram-negative and group B
streptococcal sepsis (161,162). Seven percent of individuals with diabetes will
1363have postoperative gram-negative sepsis, a rate approximately seven times higher
than that of the nondiabetic population. These complications occur more often in
patients with poor glucose control, probably caused by impaired leukocyte
function in the presence of hyperglycemia (163,164). Individuals with DM have
an increased risk of wound dehiscence and wound infection, possibly related to an
impaired immune function, with changes in phagocytosis, cell-mediated
immunity, and intracellular bactericidal activity (165).
The traditional goal for glucose control perioperatively is to maintain the
glucose level below 200 mg/dL (156,160). Significant debate continues
regarding whether strict glycemic control below 110 mg/dL may be
beneficial in critically ill patients (166,167). Perioperative hyperglycemia
(>250 mg/dL) is associated with increased susceptibility to infection and poor
wound healing. The American Diabetes Association endorses a perioperative
glucose target range of 80 to 180 mg/dL (168).
For patients with diabetes controlled with diet alone or oral medications, oral
hypoglycemic agents should be discontinued when the patient ceases oral intake
of food, and hyperglycemic episodes in the perioperative period are treated with
sliding-scale regular insulin if blood sugar levels exceed 200 mg/dL (156,160).
Insulin-dependent and type 1 diabetes pose more difficult problems. These
patients require a basal rate of insulin and a baseline intake of glucose. Type
1 diabetics are at risk of developing diabetic ketoacidosis whether or not they
are eating (156). Preoperatively, the goals include avoiding ketoacidosis and
hypoglycemia, and, to a lesser extent, hyperglycemia. Traditionally,
approximately one-third to one-half of the patient’s usual daily dose of
intermediate-acting insulin is given subcutaneously the morning of surgery.
Omit any short-acting insulin without oral intake. An infusion of 5%
dextrose should be given while being restricted from oral intake. Additional
regular insulin can be administered in the operating room as needed
(154,156). If patients are normally on a continuous insulin infusion, they may
continue at their usual infusion rate. There is no single regimen that is superior for
the intraoperative management of type 1 diabetic patients and consultation with
endocrine and anesthesia colleagues can be helpful in managing these complex
regimens.
Postoperative Management
Postoperative monitoring of patients with DM includes careful monitoring of
serum glucose levels to avoid severe hypoglycemia or hyperglycemia. If an
intravenous insulin regimen is used, blood glucose levels must be checked
every 1 to 2 hours. If a sliding-scale insulin administration is used, blood
glucose should be checked and documented approximately every 6 hours
1364until the patient is eating and stable on her preoperative regimen. The serum
glucose level should be maintained at less than 250 mg/dL, and ideally below
140 mg/dL when fasting and below 180 mg/dL with random draws (169). For
type 2 diabetics, oral hypoglycemics can be restarted when the patient resumes
eating, except with metformin, which requires normal renal and liver function
(156).
Thyroid Syndromes
Thyroid dysfunction should be suspected in any patient with a history of
hyperthyroidism, use of thyroid replacement medication or antithyroid
medication, prior thyroid surgery, or radioactive iodine therapy.
Hyperthyroidism
Diffuse toxic goiter (Graves disease) is the most common cause of
hyperthyroidism and results from abnormal stimulation of the thyroid gland by
antithyroid antibodies. Other causes of hyperthyroidism include multinodular
goiter, excess thyroid hormone, or thyroiditis. Any signs or symptoms suggestive
of weight loss, tachycardia, atrial fibrillation, goiter, or proptosis should initiate a
more extensive laboratory evaluation of thyroid function. Total thyroxin, free
triiodothyronine (T3), free thyroxin (T4), and thyroid-stimulating hormone (TSH)
tests are useful in diagnosis. In hyperthyroidism, the free T4 level will be
elevated, and the TSH level will be suppressed (170). A new diagnosis of
hyperthyroidism necessitates postponement of elective surgery until adequate
treatment with antithyroid medication is received because of the risk of thyroid
storm. Thyroid storm is associated with mortality of up to 40% (171). Stable
thyroid conditions do not require any special preoperative treatments or tests.
Ideally, a euthyroid state should be maintained for 3 months before elective
surgery. In emergent situations, β-blockers can be used to counter
sympathomimetic drive such as palpitations, diaphoresis, and anxiety. Antithyroid
medications such as propylthiouracil (PTU) or radioactive iodine do not render
patients euthyroid quickly enough for urgent surgery. Radioactive iodine requires
6 to 18 weeks to establish a euthyroid state (170). When thyroid dysfunction is
corrected and maintained for several months, elective surgery can proceed
without additional perioperative monitoring. Antithyroid medications should be
resumed with return of bowel function. If a prolonged delay in resumption of oral
intake is encountered, PTU and methimazole can be administered rectally (172).
When time does not permit establishment of a euthyroid state
preoperatively, oral administration of PTU and a b-blocker can be
implemented for 2 weeks before surgery, and with careful monitoring,
optimal results can be achieved (173). Alternatively, oral b-blockers,
1365glucocorticoids, and sodium iopanoate can be used for 5 days, followed by
surgery on day 6 (172). In the emergent setting, close monitoring of the patient
for tachycardia, arrhythmias, and hypertension is necessary. b-Blockers can
control these symptoms until definitive therapy can be initiated after recovery
from surgery.
Any signs suggestive of the development of thyroid storm—including
hemodynamic instability, tachycardia, arrhythmias, hyperreflexia, diarrhea, fever,
delirium, or CHF—mandate transfer to an intensive care setting for optimal
monitoring and management in consultation with a medical endocrinologist. Such
thyroid instability can be triggered by underlying infection, which requires
diagnosis and treatment to facilitate management of this medical emergency. The
mortality rate from thyroid storm is reportedly between 10% and 75% (172).
Treatment of thyroid storm consists of b-blockers, thioamides, iodine, iodinated
contrast agents, and corticosteroids (160). Aspirin should not be given for fever
in the patient with thyroid storm because it may interfere with the protein binding
of T4 and T3, resulting in increased free serum concentrations (160).
Hypothyroidism
The incidence of hypothyroidism is approximately 1% in the adult population,
and 5% in adults older than 50 years (170). In women older than 60 years, the
incidence of hypothyroidism may approach 6% (171). Hypothyroidism is 10
times more common in women than in men (170). Many such cases are
secondary to previous antithyroid therapy (radioactive iodine or thyroidectomy)
for hyperthyroidism. The most common primary cause of hypothyroidism is
Hashimoto thyroiditis, an autoimmune condition (170). A history of lethargy,
cold intolerance, lassitude, weight gain, fluid retention, constipation, dry skin,
hoarseness, periorbital edema, and brittle hair can be indicative of inadequate
thyroid function. In this setting, physical findings of increased relaxation phase of
deep tendon reflexes, cardiomegaly, pleural or pericardial effusions, or peripheral
edema should stimulate further investigation of thyroid function by assessment of
TSH and free T4 levels. Hypothyroidism decreases cardiac output by 30% to 50%
as a result of decreased stroke volume and heart rate (174). Hyponatremia may be
associated with hypothyroidism because of the inability of the kidneys to excrete
water (174). When elective surgery is planned for severely hypothyroid patients,
surgery should be postponed until thyroid replacement therapy is initiated (170).
In patients with mild or moderate hypothyroidism, the delay of surgery is
controversial (170).
For young patients with mild to moderate hypothyroidism, a starting dose of
1.6 μg/kg of thyroid hormone replacement can be given. In elderly patients,
thyroxin dosage (0.025 mg once a day) should be given with interval dose
1366increases every 4 to 6 weeks until the patient is euthyroid (171). Dosage levels
can ultimately be titrated against TSH levels. In severely hypothyroid patients
requiring urgent or emergent surgery, intravenous T3 or T4 may be given, along
with intravenous corticosteroids to avoid consequences of unrecognized adrenal
insufficiency (160,170).
In the immediate postoperative setting, T4 therapy can be held for 5 to 7 days
while waiting for return of bowel function because the half-life of circulating T4
is approximately 5 to 9 days (173). If more than 5 to 7 days of decreased bowel
function are expected, T4 can be given by the intramuscular or intravenous route
at approximately 80% of the oral dose (174).
Adrenal Insufficiency
Adrenal insufficiency may result in catastrophic postoperative complications,
including death. The most common cause of adrenal insufficiency in the surgical
patient is secondary to the exogenous use of corticosteroids. The physician should
ascertain whether a patient used exogenous steroids for asthma (including inhaled
steroids), malignant conditions, arthritis, or irritable bowel syndrome. The type of
steroid use, the route, the dose, the duration, and the temporal relationship to the
timing of the surgical procedure must be determined. The type of surgical
procedure and its associated stress should be taken into consideration. The use of
high doses of exogenous steroids for prolonged periods can cause circulatory
collapse, and they have adverse effects on wound healing and
immunocompetence.
The daily replacement dose of cortisol is approximately 5 to 7.5 mg of
prednisone. Suppression of the hypothalamic–pituitary–adrenal (HPA) axis
by exogenous steroids for more than a few weeks may produce relative
adrenal insufficiency. When systemic steroids are used for longer periods,
adrenal insufficiency may persist for up to 1 year. Short courses of low-dose oral
steroids (<5 mg of prednisone in a single morning dose for any duration of time,
alternate-day dosing of short-acting glucocorticoids, and any dose of
corticosteroids given for less than 3 weeks) are not thought to cause clinically
significant suppression of the HPA axis (160). More than 1,500 mcg daily for
inhaled corticosteroids (or 750 mcg daily of fluticasone) or more than 2 g per day
of class I topical glucocorticoids may cause suppression (175). If either the dose
or duration of glucocorticoid administration exceeds the preceding regimen,
biochemical tests are recommended to preoperatively evaluate the function of the
adrenal gland. The easiest and safest test to assess HPA function is the
cosyntropin stimulation test. Cosyntropin, a synthetic analog of
adrenocorticotropic hormone, is given in a dose of 250 μg intravenously, and a
1367blood sample is collected 30 minutes after the injection and assayed for plasma
cortisol. A plasma cortisol value of greater than 18 to 20 μg/dL indicates adequate
adrenal function (160,170). If the history regarding exogenous steroid use is
unclear, the cosyntropin stimulation test should be considered as a preoperative
test to determine whether the patient will need perioperative glucocorticoid
coverage. The amount of glucocorticoid replacement should be equivalent to the
normal physiologic response to surgical stress (Table 25-12) (176).
For minor surgical stress, such as colonoscopy, the glucocorticoid target is
approximately 25 mg of hydrocortisone equivalent on the day of the procedure
(176). For moderate surgical stress, for example, open cholecystectomy, the
glucocorticoid target is 50 to 75 mg of hydrocortisone equivalent on the day of
the procedure and tapered quickly for 1 to 2 days. The patient should receive her
normal daily dose preoperatively, followed by 50 mg of hydrocortisone
intravenously administered intraoperatively. For major surgical stress, such as
liver resection, the glucocorticoid target range is 100 to 150 mg hydrocortisone
equivalent on the day of the procedure, tapering rapidly over the next 1 to 2 days
to the usual dosage (176). The patient should receive her normal daily dose
preoperatively.
Administration of high-dose steroids should be stopped as soon as possible
postoperatively because they can inhibit wound healing and promote
infection. Hypertension and glucose intolerance can develop. When a prolonged
or involved procedure is performed and longer steroid use is necessary, careful
tapering may be required. The previously recommended approach was to halve
the dose of hydrocortisone on a daily basis until a dose of 25 mg is reached.
Eliminating one daily dose each day until the drug is stopped was considered the
safest method of withdrawal; no consensus on the timing or duration of steroid
tapering exists. Addison disease is uncommon but should be considered in the
differential diagnosis if the patient develops perioperative hypotension after
steroids are withdrawn. In addition to blood and isotonic fluid replacement, a
“stress” dose of steroids should be given if adrenal insufficiency is suspected and
sepsis and hypovolemia are excluded.
Cardiovascular Diseases
The incidence of perioperative cardiovascular complications decreased markedly
as a result of improvements in preoperative detection of high-risk patients,
preoperative preparation, and surgical and anesthetic techniques (177).
Preoperative Evaluation
Cardiovascular outcomes are related to baseline cardiovascular risk. Thus,
1368the goal of a preoperative cardiac evaluation is to determine the presence of
heart disease, its severity, and the potential risk to the patient during the
perioperative period. Every patient should be questioned about symptoms of
cardiac disease including chest pain, dyspnea on exertion, peripheral edema,
wheezing, syncope, claudication, or palpitations. Prescriptions for
antihypertensive, anticoagulant, antiarrhythmic, antilipid, or antianginal
medications may be the only indication of cardiac problems.
On physical examination, the presence of findings such as hypertension,
jugular venous distension, laterally displaced point of maximum impulse,
irregular pulse, third heart sound, pulmonary rales, heart murmurs,
peripheral edema, or vascular bruits should prompt a more thorough
evaluation. Laboratory evaluation of patients with known or suspected heart
disease should include a blood count and serum chemistry analysis. Patients with
heart disease tolerate anemia poorly. Serum sodium and potassium levels are
particularly important in patients taking diuretics and digitalis. BUN and
creatinine values provide information on renal function and hydration status.
Assessment of blood glucose levels may detect undiagnosed DM.
Coronary Artery Disease
[9] Coronary artery disease is a major risk factor for patients undergoing
abdominal surgery. In an adult population without a prior history of
myocardial infarction, the incidence of myocardial infarction following
surgery is 0.1% to 0.7% (178).
Because of the high mortality and morbidity associated with perioperative
myocardial infarction, considerable effort is made to predict perioperative cardiac
risk. Risk assessment is stratified into three major categories: (i) clinical
predictors, (ii) functional capacity, and (iii) surgery-specific risk (179). Clinical
predictors of increased perioperative cardiac risk include high-risk surgical
procedures, history of ischemic heart disease, history of CHF, history of transient
ischemic attack or stroke, preoperative insulin therapy, and preoperative serum
creatinine levels greater than 2.0 mg/dL. These factors are incorporated into the
RCRI (Table 25-13) (180), a prospectively validated tool that places patients into
one of four risk classes. Depending on the number of risk factors, the risk of
major cardiac events (myocardial infarction, cardiac arrest, pulmonary edema,
and complete heart block) ranges from 0.5% to 9.1% (Table 25-14).
Table 25-13 Major Cardiac Event Rates by the Revised Cardiac Risk Index
1369The patient’s functional status is assessed by a thorough history (Table 25-15),
and self-reported exercise tolerance can be used to predict perioperative risk,
based on a system of metabolic equivalents (METS) (181). Surgery-specific risk
is subdivided into high-risk procedures (emergent major operations, aortic and
vascular procedures, and prolonged surgical procedures associated with large
fluid shifts or blood loss), intermediate-risk procedures (intraperitoneal and
intrathoracic), and low-risk procedures (endoscopic, breast surgery, and
ambulatory procedures). Patients with any clinical risk factor and poor
functional capacity (METS <4) undergoing more than low-risk nonemergent
surgery should undergo preoperative testing, based on the AHA guidelines
(182).
Table 25-14 Clinical Predictors of Increased Perioperative Cardiovascular Risk
Major
Unstable coronary syndromes: acute (≤7 days) or recent (7 days–30 days) MI, unstable
or severe angina
Decompensated congestive heart failure
Significant arrhythmias (high-grade AV block, symptomatic ventricular arrhythmias,
supraventricular arrhythmias with uncontrolled ventricular rate)
Severe valvular disease
Intermediate
History of cerebrovascular disease
Prior ischemic cardiac disease
Compensated or prior congestive heart failure
Diabetes mellitus
1370Renal insufficiency
Minor
Advanced age
Abnormal ECG (LVH, LBBB, ST–T abnormalities)
Rhythm other than sinus
Uncontrolled systemic hypertension
MI, myocardial infarction; AV, atrioventricular; ECG, electrocardiogram; LVH, left
ventricular hypertrophy; LBBB, left bundle branch block.
Adapted from Fleisher LA, Beckman JA, Brown KA, et al. 2009 ACCF/AHA focused
update on perioperative beta blockade incorporated into the ACC/AHA 2007 guidelines on
perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the
American College of Cardiology Foundation/American Heart Association Task Force on
Practice Guidelines. Circulation 2009;120:e169–e276.
Table 25-15 Functional Capacity Assessment From Clinical History
Excellent
Carry 24 lb up eight steps
Carry objects that weigh 80 lb
Outdoor work (shovel snow, spade soil)
Recreation (ski, basketball, squash, handball, jog, or walk 5 mph)
Moderate
Have sexual intercourse without stopping
Walk at 4 mph on ground level
Outdoor work (garden, rake, weed)
Recreation (roller skate, dance)
Poor
Shower and dress without stopping
Basic housework
1371Walk 2.5 mph on level ground
Recreation (golf, bowl)
Adapted from Mehta RH, Bossone E, Eagle KA. Perioperative cardiac risk assessment
for noncardiac surgery. Cardiologia 1999;44:409–418.
Extent of preoperative testing depends on the level of perioperative cardiac
risk. Patients who have dyspnea of unknown origin, current or past heart failure,
prior cardiomyopathy, or with any of the above factors and no cardiac assessment
in the past 12 months should consider echocardiogram testing preoperatively
(182). Exercise stress testing before surgery can identify patients who have
ischemic heart disease not apparent at rest but are at high risk for
perioperative myocardial infarction and cardiac mortality, up to 25% and
18.5%, respectively (183). The exercise stress test must be selectively applied to
a high-risk population because its predictive value depends on the prevalence of
the disease.
Exercise stress testing is limited in some patients who cannot exercise because
of musculoskeletal disease, pulmonary disease, or severe cardiac disease.
Dipyridamole-thallium scanning may be used to overcome the limitations of
exercise stress testing. This study has a high degree of sensitivity and specificity
but a low positive predictive value (182,184).
Dobutamine stress echocardiography is another test to evaluate cardiac risk in
patients who are unable to exercise. This method identifies regional cardiac wall
motion abnormalities after dobutamine infusion. Positive and negative predictive
values are similar to those of dipyridamole-thallium testing for a perioperative
event (185). Coronary angiography should be considered only in patients who
have an indication for angiography independent of the planned surgery, such as
patients with acute coronary syndromes, unstable angina, angina refractory to
medical therapy, or high-risk results on noninvasive testing.
Preoperative testing should be used discriminately in intermediate-risk patients.
Controversy exists regarding the accuracy of these tests to provide prognostic
information beyond what is obtained from clinical risk stratification for
nonvascular procedures. Diagnostic testing should not lead to unnecessary
additional testing or harmful delays in surgery. The American College of
Cardiology and the AHA present a detailed algorithm that incorporates risk
factor stratification to guide clinicians to proceed directly to surgery, to delay
surgery and obtain preoperative noninvasive testing, or to attempt risk
factor modification (182).
Nearly two-thirds of postoperative myocardial infarctions occur during
1372the first 3 days postoperatively (189). Prevention, early recognition, and
treatment are important because myocardial infarctions that occur in the
postoperative period have mortality rates of up to 25% and are associated with
increased rates of cardiovascular death in the 6 months following surgery (186).
Postoperative tachycardia and increased preload are the most important causes of
ischemia because both conditions decrease oxygen supply to the myocardium
while simultaneously increasing myocardial oxygen demand. Tachycardia limits
the diastolic time, when the coronary arteries are perfused, which decreases the
volume of oxygen available to the myocardium. Increased preload increases the
pressure exerted by the myocardial wall on the arterioles within it, thus decreasing
myocardial blood flow.
Other factors associated with perioperative myocardial ischemia include
physiologic responses to the stress of intubation, intravenous or arterial line
placement, emergence from anesthesia, pain, and anxiety. These stresses result in
catecholamine stimulation of the cardiovascular system, resulting in increased
heart rate, blood pressure, and contractility, which may induce or worsen
myocardial ischemia. Loss of intravascular volume because of third spacing of
fluids or postoperative hemorrhage can induce ischemia (187).
Postoperative myocardial infarction is often difficult to diagnose. Chest
pain, which is present in 90% of nonsurgical patients with myocardial infarction,
may be present in only 50% of patients with postoperative infarction because
myocardial pain may be masked by coexisting surgical pain and the use of
analgesics (178). The presence of arrhythmia, CHF, or hypotension may indicate
infarction and should prompt a thorough cardiac investigation and
electrocardiographic monitoring. Measurement of creatinine kinase (CK-MB)
isoenzyme and troponin T levels are the most sensitive and specific indicators
of myocardial infarction, and assessments should be obtained for all patients
suspected of myocardial infarction (186).
Despite the high incidence of silent myocardial infarction, routine use of
postoperative ECG for all patients with cardiovascular disease is
controversial. Many patients will exhibit P-wave changes that spontaneously
resolve and do not represent ischemia or infarction. Conversely, patients with
proven myocardial infarctions may show few, if any, ECG abnormalities. The
American College of Cardiology and the AHA advise consideration of
postoperative surveillance via ST-segment monitoring for myocardial infarction
in patients with known or suspected coronary artery disease (179). In a review of
over 2,400 patients, the sensitivity of predicting postoperative cardiac events was
55% to 100%, specificity 37% to 85%, positive predictive value 7% to 57%, and
negative predictive value 89% to 100% (188). If routine screening of
asymptomatic patients is desired, ECG should be performed 24 hours following
1373surgery because significant ECG changes that occur immediately postoperatively
will persist for 24 hours. It is prudent to continue serial ECG assessments for at
least 3 days postoperatively.
Postoperative management of patients with coronary artery disease is
based on maximizing delivery of oxygen to the myocardium and decreasing
myocardial oxygen utilization. Most patients benefit from supplemental oxygen
in the postoperative period, although special care should be exercised in patients
with COPD. Oxygenation can easily be monitored by pulse oximetry. Anemia is
detrimental because of loss of oxygen-carrying capacity and resultant tachycardia
and should, therefore, be carefully corrected in high-risk patients. Although
transfusion criteria are not absolute, all patients with a hemoglobin less than 6
mg/dL, and hemoglobin of 6 to 10 mg/dL with significant cardiac risk factors
should be offered blood transfusion (189).
Patients with coronary artery disease may benefit from pharmacologic
control of hyperadrenergic states that result from increased postoperative
catecholamine production. β-Blockers decrease heart rate, myocardial
contractility, and systemic blood pressure, all of which are increased by
adrenergic stimulation. The Perioperative Ischemic Evaluation (POISE) trial, a
randomized controlled trial of metoprolol versus placebo, enrolling 8,000 patients
undergoing noncardiac surgery, revealed a reduction in cardiovascular death,
myocardial infarction, and cardiac arrest. There was an increased risk of stroke
and total mortality (190). The AHA provides the following guidelines: Continue
β-blocker therapy in patients on baseline β-blockers for treatment of cardiac
disease. Consider initiating and titrating β-blockers in patients with coronary
artery disease or high cardiac risk (as defined by the presence of more than one
clinical risk factor) who are undergoing intermediate-risk surgery (158). Therapy
should be initiated at least 1 week before surgery to allow for proper titration. The
timing and optimal duration of β-blocker therapy remain an area of uncertainty.
Nevertheless, for patients already on β-blocker therapy, they should continue it
perioperatively because abrupt withdrawal results in a rebound hyperadrenergic
state.
Prophylactic use of other agents such as nitroglycerin and calcium channel
blockers remains controversial, as data did not show a consistent benefit
toward reducing risk of ischemic cardiac events. Nitroglycerin may cause
hypotension, which may worsen cardiac status (158).
Congestive Heart Failure
Patients with CHF face a substantially increased risk of myocardial
infarction during and after surgery (191). The postoperative development of
pulmonary edema may be associated with a high mortality rate, especially if it
1374occurs in the setting of cardiac ischemia (192,193). To prevent severe
postoperative complications, CHF must be corrected preoperatively. The
signs and symptoms of CHF are listed in Table 25-16 and should be assessed
based on preoperative history and physical examination. Patients who are able to
perform usual daily activities without developing CHF are at limited risk of
perioperative heart failure.
Table 25-16 Signs and Symptoms of Congestive Heart Failure
1. Presence of an S3 gallop
2. Jugular venous distension
3. Lateral shift of the point of maximal impulse
4. Lower extremity edema
5. Basilar rales
6. Increased voltage on electrocardiogram
7. Evidence of pulmonary edema or cardiac enlargement on chest radiograph
8. Tachycardia
Treatment usually relies on aggressive diuretic therapy, although care must be
taken to avoid dehydration, which may result in hypotension during the induction
of anesthesia. Hypokalemia can result from diuretic therapy and is especially
deleterious to patients who are taking digitalis. In addition to diuretics and
digitalis, treatment often includes the use of preload- and afterload-reducing
agents. Optimal use of these drugs and correction of CHF may be aided by
consultation with a cardiologist. It is preferable to continue the usual regimen of
cardioactive drugs throughout the perioperative period.
Postoperative CHF frequently results from excessive administration of
intravenous fluids and blood products. Other common postoperative causes are
myocardial infarction, systemic infection, pulmonary embolism, and cardiac
arrhythmias. The cause of postoperative heart failure must be diagnosed because,
to be successful, treatment should be directed simultaneously to the underlying
cause. The most reliable method of detecting CHF is chest radiography, in which
the presence of cardiomegaly or evidence of pulmonary edema is a helpful
diagnostic feature.
Acute postoperative CHF frequently manifests as pulmonary edema.
Treatment of pulmonary edema may include the use of intravenous furosemide,
1375supplemental oxygen, morphine sulfate, and elevation of the head of the bed.
ECG, arterial blood gas, serum electrolytes, and renal function chemistry
measurements should be obtained expediently. If the patient’s condition does not
improve rapidly, she should be transferred to an intensive care unit.
Arrhythmias
Nearly all arrhythmias found in otherwise healthy patients are asymptomatic
and of limited consequence. In patients with underlying cardiac disease,
however, even brief episodes of arrhythmias may result in significant cardiac
morbidity and mortality.
Preoperative evaluation of arrhythmias by a cardiologist and anesthesiologist is
important because many anesthetic agents and surgical stress contribute to the
development or worsening of arrhythmias. Patients with heart disease have an
increased risk of arrhythmias, most commonly ventricular arrhythmias.
Patients taking antiarrhythmic medications before surgery should continue taking
those drugs during the perioperative period.
Patients with first-degree atrioventricular (AV) block or asymptomatic Mobitz I
(Wenckebach) second-degree AV block require no preoperative therapy. A
pacemaker is appropriate in patients with symptomatic Mobitz II second- or thirddegree AV block before elective surgery (194). In emergency situations, a pacing
pulmonary artery catheter can be used. When performing gynecologic surgery
on patients with pacemakers, it is preferable to place the electrocautery unit
ground plate on the leg to minimize interference by preventing the
pacemaker generator from sitting within the electrocautery circuit and to
maximize distance from the pacemaker device. If possible, use of bipolar
cautery devices is recommended rather than monopolar devices. In patients
with a demand pacemaker in place, the pacemaker should be converted
preoperatively to the fixed-rate (or asynchronous) mode. Patients should be
monitored continuously intraoperatively with both telemetry and continuous
pulse oximeter. Close coordination with anesthesia and cardiology is
imperative. Patients with an implantable cardioverter defibrillator device
should have their device programmed off prior to surgery and
reprogrammed postoperatively (158).
Surgery is not contraindicated in patients with bundle branch blocks or
hemiblocks (195). Perioperative mortality rates are not increased by bundle
branch block. Complete heart block rarely develops during noncardiac surgical
procedures in patients with conduction system disease. The presence of a left
bundle branch block may indicate the presence of aortic stenosis, which can
increase surgical mortality if it is severe.
1376Valvular Heart Disease
Although there are many forms of valvular heart disease, two types—aortic
and mitral stenosis—primarily are associated with significantly increased
operative risk. Patients with significant aortic stenosis appear to be at greatest
risk, which is increased in the presence of atrial fibrillation, CHF, or coronary
artery disease. Significant stenosis of aortic or mitral valves should be repaired
before elective gynecologic surgery.
Severe valvular heart disease usually is evident during physical exertion.
Common findings in such patients are listed in Table 25-17. The classic history
presented by patients with severe aortic stenosis includes exercise dyspnea,
angina, and syncope, whereas symptoms of mitral stenosis are paroxysmal and
effort dyspnea, hemoptysis, and orthopnea. Most patients have a remote history of
rheumatic fever. Severe stenosis of either valve is considered to be a valvular area
of less than 1 cm2, and diagnosis can be confirmed by echocardiography or
cardiac catheterization.
Table 25-17 Signs and Symptoms of Valvular Heart Disease
Aortic Stenosis
1. Systolic murmur at right sternal border, which radiates into carotids
2. Decreased systolic blood pressure
3. Apical heave
4. Chest radiograph with calcified aortic ring, left ventricular enlargement
5. Electrocardiogram with high R waves, depressed T waves in lead I, and precordial
leads
Mitral Stenosis
1. Precordial heave
2. Diastolic murmur at apex
3. Mitral opening snap
4. Suffused face and lips
5. Chest radiograph with left atrial dilation
6. Electrocardiogram with large P waves and right-axis deviation
1377Patients with valvular abnormalities are subdivided by the AHA into risk
groups for the development of subacute bacterial endocarditis following surgery.
Patients in the highest-risk groups should receive prophylactic antibiotics
immediately preoperatively to prevent subacute bacterial endocarditis (Table
25-5). As defined by the AHA, only patients with prosthetic cardiac valves,
congenital heart disease, and cardiac transplantation who develop cardiac
valvulopathy should receive perioperative endocarditis prophylaxis (26). All other
patients do not require antibiotics for subacute bacterial endocarditis prophylaxis.
Routine prophylaxis for GI or GU procedures is not recommended. Only in cases
of a known infection of the GI or GU tract should antibiotics coverage for
enterococcus with amoxicillin or ampicillin or vancomycin be provided.
Patients with aortic and mitral stenosis tolerate sinus tachycardia and other
tachyarrhythmias poorly. In patients with aortic stenosis, sufficient levels of
digitalis should be provided to correct preoperative tachyarrhythmias, and
propranolol may be used to control sinus tachycardia. Patients with mitral valve
stenosis often have atrial fibrillation and, if present, digitalis should be used to
reduce rapid ventricular response.
Patients with mechanical heart valves usually tolerate surgery well (196). These
patients should receive antibiotic prophylaxis (Table 25-5). If the patient is taking
aspirin therapy, it should be discontinued 1 week before the procedure and
restarted as soon as it is considered safe by the surgeon. Patients with a bileaflet
aortic valve with no risk factors (atrial fibrillation, previous thromboembolism,
left ventricular dysfunction, a hypercoagulable state, older-generation
thrombogenic valve) generally do not require anticoagulation bridging. Warfarin
should be stopped 72 hours prior to the procedure and resumed 24 hours after the
procedure. In contrast, patients with a mechanical aortic valve and any abovementioned risk factor, or a mechanical mitral valve, should be bridged with
intravenous unfractionated heparin or subcutaneous low–molecular-weight
heparin when the INR falls below 2. Anticoagulation should be stopped 6 to 8
hours (if using heparin drip) or 12 hours (if using low–molecular-weight heparin)
before the surgery. Bridging anticoagulation should be restarted postoperatively
when the patient’s bleeding risk is low and can be stopped when the INR reaches
therapeutic levels (197).
In the postoperative period, patients with mitral stenosis should be
carefully monitored for pulmonary edema because they may not be able to
compensate for the amount of intravenous fluid administered during surgery.
Prevention of tachycardia is important, as it may lead to pulmonary edema.
Patients with mitral stenosis frequently have pulmonary hypertension and
decreased airway compliance. They may require more pulmonary support and
therapy postoperatively, including prolonged mechanical ventilation.
1378For patients with significant aortic stenosis, it is imperative that a sinus
rhythm be maintained during the postoperative period. Even sinus
tachycardia can be deleterious because it shortens the diastolic time. Bradycardia
less than 45 beats per minute should be treated with atropine. Supraventricular
dysrhythmias may be controlled with verapamil or direct-current cardioversion.
Particular attention should be provided to the maintenance of proper fluid status,
digoxin levels, electrolyte levels, and blood replacement.
Hypertension
Patients with controlled essential hypertension have no increased risk of
perioperative cardiac morbidity or mortality. Patients with concomitant heart
disease are at elevated risk and should be completely evaluated by a cardiologist
preoperatively. Laboratory studies should include an ECG, chest radiography,
blood count, urinalysis, and serum electrolytes and creatinine measurement.
Antihypertensive medications should be continued perioperatively. β-Blockers
should be continued, parenterally if necessary, to avoid rebound tachycardia,
hypercontractility, and hypertension. Clonidine may cause significant rebound
hypertension, if withdrawn acutely. Angiotensin-converting enzyme inhibitor
agents and angiotensin II receptor antagonists are associated with increased
intraoperative hypotension and perioperative renal dysfunction possibly resulting
from a hypovolemic state. It may be prudent to withhold these agents on the
morning of surgery and resume them postoperatively when good renal function
and euvolemia are confirmed (158).
[9] Patients with diastolic pressures higher than 110 mm Hg or systolic
pressures higher than 180 mm Hg should receive medication to control their
hypertension before surgery. β-Blockers may be particularly effective agents for
treatment of preoperative hypertension (179).
Postoperative hypertension is usually treated parenterally because
gastrointestinal absorption may be diminished, and transdermal absorption can be
erratic in patients who are cold and rewarming. Commonly used parenteral
antihypertensives are listed in Table 25-18.
Table 25-18 Common Parenteral Antihypertensives
1379Perioperative Antiplatelet Agents
Increasing numbers of patients undergo coronary revascularization procedures,
otherwise known as coronary artery bypass grafting, or percutaneous coronary
intervention, typically stent placement. With the evolution of bare-metal and
drug-eluting stents, perioperative management of cardiovascular thrombotic risk
versus perioperative bleeding and mortality is challenged. Given that drug-eluting
stents generally require 12 months’ treatment with dual agent aspirin and
thienopyridine (i.e., clopidogrel), the American College of Cardiology and
American Heart Association (ACC/AHA) guidelines recommend avoiding
elective surgery within 12 months of drug-eluting stent placement. When surgery
cannot wait, the ACC/AHA recommends continuation of aspirin perioperatively,
discontinuation of thienopyridine 5 days prior to surgery, and resuming it as soon
as possible postoperatively. Ultimately the risk of perioperative morbidity
secondary to bleeding must be weighed against the risk of repeat thrombosis and
cardiovascular morbidity and mortality. If a patient requires new placement of a
cardiac stent and noncardiac surgery in the following 12 months, placement of a
bare-metal stent is recommended rather than a drug-eluting stent, as these require
only 4 to 6 weeks of dual-antiplatelet therapy. Again, aspirin should be continued
perioperatively. Following a newly placed bare-metal stent, noncardiac surgery
should be scheduled at least 30 to 45 days after the stent placement to decrease
cardiac morbidity (179).
Hemodynamic Monitoring
Hemodynamic monitoring is integral to the perioperative management of patients
with cardiovascular and pulmonary diseases. The desire for the quantitative
estimate of cardiac function resulted in the development of bedside PAC.
Before the development of the pulmonary artery catheter, central venous
pressure (CVP) measurement was used to assess intravascular volume status and
cardiac function. To measure the CVP, a catheter is placed in the central venous
system, most frequently the superior vena cava, allowing an estimation of right
atrial pressure. If the pulmonary vascularity and left ventricular function are
normal, the CVP accurately reflects the left ventricular end-diastolic pressure
(LVEDP). The LVEDP reflects cardiac output or systemic perfusion and was
considered the standard estimator of left ventricular pump function. If right
ventricular function is normal, the CVP accurately reflects intravascular volume.
When left or right ventricular dysfunction is present, measurement of
pulmonary artery occlusion pressure can be used to accurately assess volume
status and cardiovascular function. A baloon-tipped PAC, known as a Swan-Ganz
catheter, is an invasive tool used to improve detection in cardiovascular function
changes over clinical observation (198).
1380The distal lumen of the catheter, which is beyond the balloon occluding the
pulmonary artery, measures left atrial pressure (LAP) and, in the absence of
mitral valvular disease, LAP approximates LVEDP. Pulmonary–capillary
wedge pressure (PCWP) equals the LAP, which equals LVEDP and is
normal at 8 to 12 mm Hg. Because the standard pulmonary artery catheter has
an incorporated thermistor, thermodilution studies can be performed to determine
cardiac output. Knowledge of the cardiac output is helpful in establishing
cardiovascular diagnoses. For example, a patient with hypotension, low-to-normal
wedge pressure, and a cardiac output of 3 L per minute is most likely
hypovolemic. The same patient with a cardiac output of 8 L per minute is
probably septic with resultant low systemic vascular resistance.
The effect of PAC use on patient outcome is controversial. Several large trials
did not confer a definite benefit to PAC use. A randomized controlled trial of
1,994 high-risk (American Society of Anesthesiologists class III or IV risk)
patients aged 60 or older undergoing urgent or elective major noncardiac surgery
compared outcomes of those who underwent PAC placement versus standard
care. Results analyzed by a blinded assessor revealed no benefit of PAC over
standard care with central venous catheters (199). Another randomized controlled
trial enrolling 65 intensive care units in the United Kingdom found no difference
in mortality among critically ill patients managed with or without a PAC (200). A
meta-analysis of 13 randomized controlled trials of PAC use found no significant
difference in mortality rates and an increased use of inotropes and intravenous
vasodilators (201). Routine preoperative use of PAC in noncardiac surgery
patients is no longer indicated. Use of PAC in critically ill patients
postoperatively remains controversial.
1381Hematologic Disorders
The presence of hematologic disorders, although uncommon in gynecologic
patients, significantly affects operative morbidity and mortality and should be
considered routinely in preoperative evaluation. Preoperative assessment should
include consideration of anemia, platelet and coagulation disorders, white blood
cell function, and immunity.
Anemia
Moderate anemia is not in itself a contraindication to surgery because it can be
corrected by transfusion. If possible, surgery should be postponed until the cause
of the anemia can be identified and the anemia corrected without resorting to
transfusion. By tradition, anesthetic and surgical practice recommended a
hemoglobin level of greater than 10 g/dL or a hematocrit of greater than 30%.
Data suggest a lower tolerance for pre- and intraoperative transfusion threshold to
improve intra- and postoperative morbidity and mortality (202). It remains that no
universal “transfusion threshold” is agreed upon, but that a hematocrit of less than
24% should prompt strong consideration (203). The circulating blood volume
provides oxygen-carrying capacity and tissue oxygenation. Individual tolerance of
anemia depends on overall physical fitness and cardiovascular reserve.
Maintenance of adequate tissue perfusion requires an increase in cardiac output as
hemoglobin concentration falls (189). In the healthy patient, oxygen delivery is
unchanged when it falls below 7 g/dL (204). In contrast, a patient with ischemic
heart disease will not tolerate anemia as well (205). The presence of cardiac,
pulmonary, or other serious illness justifies a more conservative approach to the
management of anemia. Patients with long-standing anemia may have normal
blood volume levels and tolerate surgical procedures well. There is no evidence
that mild to moderate anemia increases perioperative morbidity or mortality
(205).
Autologous blood donation is advocated as a safer alternative for the patient;
however, the use of preoperative autologous blood donation has come under
scrutiny (206). Preoperative autologous blood may lead to more liberal blood
transfusion, iatrogenic anemia, volume overload, and bacterial
contamination (207). Preoperative autologous blood donation is poorly cost
effective (208). The National Heart, Lung, and Blood Institute does not
recommend collection of autologous blood for procedures with a likelihood of
transfusion less than 10%, such as uncomplicated abdominal and vaginal
hysterectomies (209).
Platelet and Coagulation Disorders
1382Surgical hemostasis is provided by platelet adhesion to injured vessels, which
plugs the opening as the coagulation cascade is activated, resulting in the
formation of fibrin clots. Functional platelets and coagulation pathways are
necessary to prevent excessive surgical bleeding. Platelet dysfunction is
encountered preoperatively more frequently than coagulation disorders.
Platelets may be deficient in both number and function. The normal peripheral
blood count is 150,000 to 400,000 per mm3, and the normal life span of a platelet
is approximately 10 days. Although there is no clear-cut correlation between the
degree of thrombocytopenia and the presence or amount of bleeding, several
generalizations can be made. If the platelet count is higher than 100,000/mm3 and
the platelets are functioning normally, there is little chance of excessive bleeding
during surgical procedures. Patients with a platelet count higher than 75,000/mm3
almost always have normal bleeding times, and a platelet count higher than
50,000/mm3 is probably adequate. A platelet count lower than 20,000/mm3
often will be associated with severe and spontaneous bleeding. Platelet counts
higher than 1,000,000/mm3 are often, paradoxically, associated with bleeding.
In patients with immune destruction of platelets, human leukocyte antigen
(HLA)–matched donor-specific platelets may be required to prevent rapid
destruction of transfused platelets. If surgery can be postponed, a hematology
consultation should be obtained to identify and treat the cause of the platelet
abnormality.
Abnormally low platelet counts result from either decreased production or
increased consumption of platelets. Although there are numerous causes of
thrombocytopenia, most are exceedingly uncommon. Decreased platelet
production may be drug induced and is associated with the use of sulfonamides,
cinchona alkaloids, thiazide diuretics, NSAIDs, gold salts, penicillamine,
anticonvulsants, and heparins (210). Decreased platelet count is a feature of
several diseases, including vitamin B12 and folate deficiency, aplastic anemia,
myeloproliferative disorders, renal failure, and viral infections. Inherited
congenital thrombocytopenia is extremely rare. More commonly,
thrombocytopenia results from immune destruction of platelets by diseases such
as idiopathic thrombocytopenia purpura and collagen vascular disorders.
Consumptive thrombocytopenia is a feature of disseminated intravascular
coagulation, which is encountered most frequently in conjunction with sepsis
or malignancy in the preoperative population.
Platelet dysfunction most often is acquired, but may be inherited. Occasionally,
a patient with von Willebrand disease, the second most common inherited
disorder of coagulation, may be encountered in the preoperative setting. Platelet
dysfunction is more difficult to diagnose than abnormalities of platelet count. A
1383history of easy bruising, petechiae, bleeding from mucous membranes, or
prolonged bleeding from minor wounds may signify an underlying abnormality of
platelet function. Such dysfunction can be identified with the help of a bleeding
time, but full characterization of the underlying etiology should be carried out
with hematologic consultation. If at all possible, surgery should be postponed
until therapy is instituted.
Disorders of the coagulation cascade often are diagnosed through a personal or
family history of excessive bleeding during minor surgery, childbirth, or menses.
Many women with menorrhagia are referred for surgical intervention and require
a thorough preoperative evaluation for possible inherited disorders of hemostasis,
such as factor VIII (hemophilia), factor IX (Christmas disease), factor XI
deficiencies, and von Willebrand disease. Von Willebrand disease is the most
common hereditary bleeding disorder, with prevalence in the general population
of roughly 1%. Seventy percent to 90% of women with von Willebrand disease
have menorrhagia (211). Identified women can be treated effectively with
desmopressin nasal spray, avoiding unanticipated or excessive bleeding during
surgery (212). In the absence of a genetic diagnosis, the diagnosis of von
Willebrand disease is difficult and involves a combination of clinical and
laboratory assessments, including von Willebrand factor antigen and von
Willebrand factor functional activity or ristocetin cofactor assay (212).
Physiologic fluctuations occur with von Willebrand factor levels, requiring repeat
testing and consultation or referral to a hematologist. It is recommended that
women presenting with menorrhagia without obvious pelvic abnormalities should
be routinely screened for inherited bleeding disorders before undergoing invasive
procedures.
There are few commonly prescribed drugs that affect coagulation factors, the
exceptions being warfarin and heparin. Disease states that may be associated with
decreased coagulation factor levels are primarily liver disease, vitamin K
deficiency (secondary to obstructive biliary disease, intestinal malabsorption, or
antibiotic reduction of bowel flora), and disseminated intravascular coagulation.
Preoperative laboratory screening for coagulation deficiencies is controversial.
Routine screening is not warranted in patients who do not have historical
evidence of a bleeding problem (213). Patients who are seriously ill or who will
be undergoing extensive surgical procedures should undergo testing
preoperatively to determine PT, partial thromboplastin time, fibrinogen level, and
platelet count.
Blood Component Replacement
Packed red blood cells (PRBCs), which may be stored for several weeks, are used
for most postoperative transfusions. Most clotting factors are stable for long
1384periods. The exceptions are factors V and VIII, which decrease to 15% and 50%
of normal, respectively. Most hematologic problems observed in the
postoperative period are related to perioperative bleeding and blood component
replacement. Although the primary cause of the bleeding is usually lack of
surgical hemostasis, other factors, including deranged coagulation, may
compound the problem. Such coagulopathy can result from massive transfusion
(less than one blood volume) and is thought to be caused by dilution of platelets
and labile coagulation factors by platelet- and factor-poor PRBCs, fibrinolysis,
and disseminated intravascular coagulation.
A review in Transfusion questioned the traditional practice of limiting blood
component replacement in massive transfusion. Summarizing 14 articles and
encompassing nearly 4,600 patients, the conclusions note a decrease in all-cause
mortality with more liberal transfusion of platelets and fresh frozen plasma (FFP)
(214).
A task force for the American Society of Anesthesiologists recommended
critical values for replacement in patients with massive transfusion and
microvascular bleeding (189):
1. Platelet transfusion usually is indicated for counts less than 50,000/mm3
(with intermediate platelet counts, i.e., 50,000/mm3 to 100,000/mm3, the
transfusion of platelet concentrates should be based on the risk of more
significant bleeding).
2. FFP therapy is indicated if the prothrombin or APTT values exceed 1.5
times the normal value.
3. Cryoprecipitate transfusion is indicated if fibrinogen concentrations
decrease to less than 80 to 100 mg/dL.
Cryoprecipitate transfusions are recommended for prophylaxis in nonbleeding
perioperative patients with fibrinogen deficiencies or von Willebrand disease
refractory to desmopressin acetate and bleeding patients with von Willebrand
disease (212).
Donor blood is stored in the presence of citrate, which chelates calcium to
prevent clotting, increasing the theoretical risk of hypocalcemia following
massive transfusion. Citrate is metabolized at a rate equivalent to 20 U of blood
transfused per hour; thus, routine supplementation of calcium is unnecessary.
Close monitoring of calcium levels is required in patients with hypothermia, liver
disease, or hyperventilation because citrate metabolism may be slowed. Hepatic
metabolism of citrate to bicarbonate can result in metabolic alkalosis following
transfusion, resulting in subsequent hypokalemia, despite the high level of
extracellular potassium in stored blood.
1385Pulmonary Disease
In patients undergoing abdominal surgery, anesthesia-related airway irritation,
splinting of breathing related to pain, and immobilization lead to several
pulmonary physiologic changes, including a decrease in the functional residual
capacity (FRC), an increase in ventilation–perfusion mismatching, and impaired
mucociliary clearance of secretions from the tracheobronchial tree (215). Risk
factors for postoperative pulmonary complications include the following
(Table 25-19) (216):
Upper abdominal or thoracic, or abdominal aortic aneurysm surgery
Surgical procedure time longer than 3 hours
COPD
Smoking within 2 months of surgery
Use of pancuronium for general anesthesia
New York Heart Association Class II pulmonary hypertension
General anesthesia
Emergency surgery
Poor nutrition (serum albumin <3.5 mg/dL or BUN <8)
Healthy, asymptomatic patients do not require preoperative pulmonary
function testing, arterial blood gas measurements, or chest x-rays. Most
patients with abnormal chest x-rays have history or physical examination findings
suggestive of pulmonary disease.
Table 25-19 Predictors of Postoperative Pulmonary Complicationsa
Parameter Value
Maximal breathing capacity <50% predicted
FEV1 <1 L
FVC <70% predicted
FEV1/FVC <65% predicted
Pao2 <60 mm Hg
PaCO2 >45 mm Hg
aComplication defined as atelectasis or pneumonia.
1386FEV, forced expiration volume; FVC, forced vital capacity; Pao2, partial pressure of
oxygen, arterial; PaCO2, partial pressure of carbon dioxide, arterial.
Adapted from Blosser SA, Rock P. Asthma and chronic obstructive lung disease. In:
Breslow MJ, Miller CJ, Rogers MC, eds. Perioperative Management. St. Louis, MO:
Mosby; 1990:259–280.
Asthma
Asthma affects approximately 22 million individuals in the United States,
including 6% of children (217). It is characterized by a history of episodic
wheezing, physiologic evidence of reversible obstruction of the airways either
spontaneously or following bronchodilator therapy, and pathologic evidence of
chronic inflammatory changes in the bronchial submucosa.
Multiple stimuli are noted to precipitate or exacerbate asthma, including
environmental allergens or pollutants, respiratory tract infections, exercise, cold
air, emotional stress, nonselective β-adrenergic blockers, and NSAIDs.
Management of asthma includes removal of the inciting stimuli and use of
appropriate pharmacologic therapy to relax the airways and alleviate
inflammation (217). The optimal therapy for asthma involves managing the acute
symptoms and long-term management of the inflammatory component of the
disease.
Pharmacotherapy of Asthma
The treatment of asthma is divided into long-term control modalities and shortterm modalities. Recognizing the underlying pathophysiology in asthma as an
inflammatory condition, inhaled corticosteroids are the cornerstone for
maintenance therapy. Onset of action is slow (several hours), and up to 3
months of steroid therapy may be required for optimal improvement of bronchial
hyperresponsiveness. Even with acute bronchospasm, steroid treatment can
enhance the beneficial effect of β-adrenergic treatment. During acute
exacerbations of asthma, a short course of oral steroids, in addition to inhaled
steroids, may be necessary. For adults with chronic asthma, only a minority will
require chronic oral steroid therapy. Patients taking oral steroids should receive
intravenous steroid support in the form of 100 mg of hydrocortisone IV every 8
hours perioperatively, sharply tapering within 24 hours of surgery to avoid
adrenal insufficiency. Other long-term control therapies include (217):
1. Leukotriene modifiers (i.e., montelukast): These agents interfere with
leukotrienes, substances released from mast cells, eosinophils, and basophils
important in the inflammatory response.
2. Cromolyn sodium: Highly active in the treatment of seasonal allergic asthma
1387in children and young adults. It is usually not as effective in older patients or
in patients in whom asthma is not allergic in nature.
3. Immunomodulators: Omalizumab, a monoclonal antibody to immunoglobulin
E (IgE), has gained support for prevention and may be an important adjunct in
symptomatic suppression.
4. Long-term β2-adrenergic agonists (i.e., salmeterol): Although not appropriate
for single-agent management or use in mild disease, they are an important
adjunct in the suppression of symptoms in patients with significant disease.
5. Methylxanthines (i.e., theophylline): These were relegated to third-line status
in the management of asthma. Theophylline toxicity can develop when other
drugs such as ciprofloxacin, erythromycin, allopurinol, Inderal, or cimetidine
are concomitantly administered. Therapeutic serum levels must be monitored
closely.
β2-Adrenergic agonists remain the first-line drugs for acute asthma
attacks. These drugs, inhaled four to six times daily, rapidly relax smooth muscle
in the airways and are effective for up to 6 hours. Studies of β2-agonists in
chronic asthma failed to show any influence of these agents on the inflammatory
component of asthma. β2-Agonists are recommended for short-term relief of
bronchospasm (“rescue inhalers”) or as first-line treatment for patients with very
infrequent symptoms or symptoms provoked solely by exercise (217).
Anticholinergic agents are weak bronchodilators that work via inhibition of
muscarinic receptors in the smooth muscle of the airways. The quaternary
derivatives, such as ipratropium bromide (Atrovent), are available in an inhaled
form that is not absorbed systemically. Anticholinergic drugs may provide
additional benefit in conjunction with standard steroid and bronchodilator therapy
but should not be used as single-agent therapy because they do not inhibit mast
cell degranulation, do not have any effect on the late response to allergens, and do
not have an anti-inflammatory effect (217).
Perioperative Management of Asthma
In patients with asthma, elective surgery should be postponed whenever
possible until pulmonary function and pharmacotherapeutic management
are optimized. Recent guidelines of the American Academy of Allergy, Asthma
and Immunology recommend three interventions to reduce perioperative
pulmonary complications related to asthma (217):
1. Review the patient’s asthmatic control, including the need for oral steroids.
2. Optimize the patient’s symptomatic control through the use of long-acting
1388pharmacotherapy, including oral steroids if needed.
3. For patients on oral steroid therapy within 6 months of therapy or for patients
using large doses of inhaled corticosteroids, consider perioperative stress dose
steroids.
For mild asthma, the use of inhaled β-adrenergic agonists preoperatively may
be all that is required. For chronic asthma, optimization of steroid therapy will
greatly decrease alveolar inflammation and bronchiolar hyperresponsiveness.
Inhaled β2-agonists should be added to therapy as needed for further control of
asthma. Each drug prescribed should be used in maximal dosage before adding an
additional agent. Preoperative treatment with combined corticosteroids and an
inhaled β2-adrenergic agonist for a 5-day period may decrease the risk of
postoperative bronchospasm in patients with asthma (218). For patients
undergoing emergent surgery who have significant bronchoconstriction, a
multimodal approach should be instituted, including aggressive bronchodilator
inhalation therapy and intravenous steroid therapy. The role of spirometry,
outside of cardiothoracic procedures, has limited value in predicting postoperative
pulmonary complications and should be limited to the confirmation of
undiagnosed obstructive pulmonary disease (219).
Chronic Obstructive Pulmonary Disease
[9] COPD is the greatest risk factor for the development of postoperative
pulmonary complications. COPD encompasses both chronic bronchitis and
emphysema, disease entities that often occur in tandem. Cigarette smoke is
implicated in the pathogenesis of both, and any treatment plan must include
cessation of smoking (220). Chronic bronchitis is defined as the presence of
productive cough on most days for at least 3 months per year and for at least 2
successive years (221). It is characterized by chronic airway inflammation and
excessive mucus production. The histologic changes of emphysema include
destruction of alveolar septa and distension of airspaces distal to terminal alveoli.
The destruction of alveoli results in air trapping, loss of pulmonary elastic recoil,
collapse of the airways in expiration, increased work of breathing, and significant
ventilation–perfusion mismatching (221). The impaired ability to cough
effectively and clear secretions predisposes patients with COPD to atelectasis and
pneumonia in the postoperative period.
Patients with COPD and a history of heavy smoking account for most
postoperative pulmonary complications in gynecologic surgical patients. The
severity of COPD can be determined preoperatively via a thorough history and
physical examination. According to recommendations regarding the use of
preoperative pulmonary function tests by the American College of Physicians,
1389these should be reserved for individuals in whom COPD is suspected, but
unconfirmed (219,222). Typically, patients with COPD demonstrate impaired
expiratory air flow, manifested by diminished FEV1, forced vital capacity (FVC).
The preoperative preparation for patients at risk for postoperative
pulmonary complications should include cessation of smoking for as long as
possible preoperatively. One to 2 weeks of cessation decreases sputum volume.
Two months of smoking abstinence is required to significantly lower the risk of
postoperative pulmonary complications (215). Longer periods of abstinence can
be counseled in patients undergoing elective surgery.
In patients with severe COPD, maximum improvement in airflow limitation
can be achieved with a therapeutic trial of high-dose oral corticosteroids followed
by a 2-week trial of high-dose inhaled steroid (beclomethasone 1.5 mg per day or
the equivalent) in addition to inhaled bronchodilator therapy. Ideally, oral and
inhaled steroid therapy should be initiated 1 to 2 weeks preoperatively. Inhaled
steroids, in particular, address the inflammatory component of COPD. Oral
steroid therapy initiated preoperatively should be maintained throughout the
perioperative period and then tapered postoperatively. β-Adrenergic agonist
therapy can be initiated at least 72 hours preoperatively and is beneficial in
patients who demonstrate either clinical or spirometric improvement on
bronchodilators.
Patients with COPD and an active bacterial infection suggested by
purulent sputum should undergo a full course of antibiotic therapy before
surgery. The antibiotic used should cover the most likely etiologic organisms,
Streptococcus pneumoniae and Haemophilus influenzae. In any patient with acute
upper respiratory infection, surgery should be delayed if possible. The use of
antibiotics to sterilize the sputum in the absence of evidence of an acute infection
should be avoided because this practice may lead to bacterial resistance.
Aggressive pulmonary toilet, including incentive spirometry, chest physical
therapy, and continuous positive airway pressure devices, reduced the risk of
perioperative pulmonary complications in patients undergoing upper abdominal
surgery, many of which can be instituted preoperatively (222).
Postoperative Pulmonary Management
Atelectasis
Atelectasis accounts for more than 90% of all postoperative pulmonary
complications. The pathophysiology involves a collapse of the alveoli, resulting
in ventilation–perfusion mismatching, intrapulmonary venous shunting, and a
subsequent drop in the PaO2. Collapsed alveoli are susceptible to superimposed
infection, and if managed improperly, atelectasis will progress to pneumonia.
1390Despite the decrease in PaO2, the partial pressure of carbon dioxide (PCO2)
remains unaffected unless atelectatic changes progress to large volumes of the
lung or pre-existing lung disease is present.
Auscultation of the chest may reveal decreased breath sounds at the bases or
dry rales upon inspiration. Percussion of the posterior thorax may suggest
elevation of the diaphragm. Radiologic findings include the presence of horizontal
lines or plates on posteroanterior chest x-rays, occasionally with adjacent areas
containing hyperinflation. These changes are most pronounced during the first 3
postoperative days.
Therapy for atelectasis should be aimed at expanding the alveoli and increasing
the FRC. The most important maneuvers are those that promote maximal
inspiratory pressure, which is maintained for as long as possible. It can be
achieved with aggressive supervised use of incentive spirometry, deep breathing
exercises, coughing, and in some cases, the use of positive expiratory pressure
with a mask (continuous positive airway pressure). Oversedation should be
avoided, and patients should be encouraged to ambulate and change positions
frequently.
Cardiogenic (High-Pressure) Pulmonary Edema
Cardiogenic pulmonary edema can result from myocardial ischemia,
myocardial infarction, or from intravascular volume overload, particularly
in patients who have low cardiac reserve or renal failure. The process usually
begins with an increase in the fluid in the alveolar septa and bronchial vascular
cuffs, ultimately seeping into the alveoli. Complete filling of the alveoli impairs
secretion and production of surfactant. Concomitant with alveolar flooding, there
is a decrease in lung compliance, impairment of the oxygen diffusion capacity,
and an increase in the arteriolar–alveolar oxygen gradient. Ventilation–perfusion
mismatching in the lung results in a decrease in the PaO2, resulting eventually in
decreased oxygenation of the tissues and impairment of cardiac contractility.
Symptoms may include tachypnea, dyspnea, wheezing, and use of the
accessory muscles of respiration. Clinical signs may include distension of the
jugular veins, peripheral edema, rales upon auscultation of the lungs, and an
enlarged heart. Radiographic findings may include the presence of bronchiolar
cuffing and increased interstitial fluid markings extending to the periphery of the
lung. The diagnosis can be confirmed with the use of central hemodynamic
monitoring, which will denote an elevated CVP and, more specifically, an
elevation in the PCWP.
The patient’s volume status should be evaluated thoroughly. In addition,
myocardial ischemia or infarction should be ruled out by performing ECG and
analyzing cardiac enzyme levels. The management of cardiogenic pulmonary
1391edema includes oxygen support, aggressive diuresis, and afterload reduction to
increase the cardiac output. In the absence of myocardial infarction, an inotropic
agent may be used. Mechanical ventilation should be reserved for cases of acute
respiratory failure.
Noncardiogenic Pulmonary Edema (Adult Respiratory Distress Syndrome)
In contrast with cardiogenic pulmonary edema, in which alveolar flooding is
a result of an increase in the hydrostatic pressure of the pulmonary
capillaries, alveolar flooding in patients with adult respiratory distress
syndrome (ARDS) is the result of an increase in pulmonary capillary
permeability. The primary pathophysiologic process is one of damage to the
capillary side of the alveolar–capillary membrane. This damage results in rapid
movement of fluid containing high concentrations of protein from the capillaries
to the pulmonary parenchyma and alveoli. Lung compliance decreases and
oxygen diffusion capacity is impaired, resulting in hypoxemia. If not managed
aggressively, respiratory failure may result. The causes of ARDS include shock,
sepsis, multiple red blood cell transfusions, aspiration injury, inhalation
injury, pneumonia, pancreatitis, disseminated intravascular coagulation, and
fat emboli (244). Twenty-eight-day mortality is reported between 25% and 40%,
with overall mortality as high as 70% (223). Irrespective of the cause, which
should be identified and treated if possible, the evolving clinical picture and
management are very similar.
Clinically, ARDS passes through several stages. Initially, patients develop
tachypnea and dyspnea with no remarkable findings on clinical evaluation or on
chest x-ray. Chest x-rays eventually reveal bilateral diffuse pulmonary infiltrates.
As lung compliance becomes impaired, FRC, tidal volume, and vital capacity
decrease. The PaO2 decreases and, characteristically, increases only marginally
with oxygen supplementation. An attempt should be made to maintain the arterial
oxygen level above 90%. This may be achievable initially by administering
oxygen by mask. For patients with severe hypoxemia, endotracheal intubation
with positive-pressure ventilation should be instituted.
Hemodynamic monitoring is invaluable and should be initiated early in the
course of the disease process in the appropriate intensive care unit setting.
Patients with any evidence of fluid overload should receive aggressive diuresis,
whereas others may require fluid resuscitation for maintenance of tissue perfusion
while the PCWP is maintained below 15 mm Hg. Pulmonary wedge pressure may
be falsely elevated when PEEP is being applied. The goal of management is to
maintain the lowest PCWP, with acceptable cardiac output and blood
pressure. In the setting of hypotension and oliguria, inotropic support with
dopamine or dobutamine or both is helpful.
1392With aggressive management, particularly if the inciting cause is identified
and treated, ARDS can be reversed during the first 48 hours with few
sequelae. After the first 48 hours, progression of the ARDS will cause lung
damage that may leave residual pulmonary fibrosis. The long-term outcome is
usually apparent within the first 10 days, at which time approximately half of
patients are weaned from ventilatory support or have died (223).
Renal Disease
The need for surgical intervention in patients with renal impairment resulted in
the development of a very specialized medical approach to their care. Precautions
are necessary to compensate for the kidneys’ impaired ability to regulate fluids
and electrolytes and excrete metabolic waste products. Equally important are the
unique problems that develop in patients with chronic renal impairment, including
an increased risk of sepsis, coagulation defects, impaired immune function and
wound healing, and a propensity to develop specific acid–base abnormalities.
Special consideration must be given to a variety of different medications,
anesthetic agents, and numerous hematologic and nutritional factors that are
important in the successful surgical care of patients with renal insufficiency.
Management of fluid levels and cardiovascular hemodynamics in patients
with acute or chronic renal impairment is paramount. Intravascular fluid
volume changes that lead to hypertension or hypotension are very common in
these patients and often are difficult to manage secondary to autonomic
dysfunction, acidosis, and other problems that are inherent to the underlying
kidney disease. Dialysis-dependent patients are especially susceptible to
postoperative complications, and invasive monitoring should be considered to
help guide fluid replacement and avoid volume overload.
Co-management of dialysis-dependent patients with their nephrologists is
imperative to reduce morbidity and mortality in the perioperative period. For
those patients with end-stage renal disease (ESRD) on hemodialysis, dialysis is
frequently recommended the day prior to surgery to allow patients to be as
euvolemic as possible prior to their procedure. Patients who perform peritoneal
dialysis may increase their regimen during the week preceding surgery to offset
potential delays in resumption of peritoneal dialysis postoperatively. Dialysis
should be resumed according to the patient’s normal schedule postoperatively. A
short-lived but rather significant fall in the number of platelets occurs during
dialysis; in addition, heparin is used in hemodialysis equipment to prevent
clotting. Because of these factors and concerns about postoperative bleeding,
dialysis is usually avoided during the first 12 to 24 hours following surgery. If
patients require significant intraoperative volume repletion or blood transfusion,
they are at an increased risk for volume overload and earlier dialysis may be
1393necessary to prevent significant volume overload.
The major hematologic concern in patients with chronic renal
insufficiency is the increased incidence of bleeding. These bleeding problems
are secondary to abnormal bleeding times and, in particular, disorders of platelet
secretion, platelet aggregation, and decreased von Willebrand factor activity
(224). Anemia, which is common in patients with renal insufficiency, should be
treated preoperatively with erythropoiesis-stimulating agents to allow patients to
enter surgery at their target hemoglobin concentration. Checking a bleeding time
is no longer recommended prior to surgery in patients with ESRD as a normal
bleeding time does not predict the safety of surgical procedures. Optimizing
preoperative hemoglobin, appropriate dialysis timing, and the use of
desmopressin, cryoprecipitate, or conjugated estrogens can reduce uremic
bleeding (225,226).
Impaired kidney function causes phosphate retention by the kidney and
impaired vitamin D metabolism. Therefore, hypocalcemia is common in patients
with renal insufficiency, but tetany and other signs of hypocalcemia are relatively
uncommon because metabolic acidosis increases the level of ionized calcium.
Oral phosphate binders, such as aluminum hydroxide (1 to 2 g per meal), and
dietary phosphate restriction (1 g per day) is the usual treatment for
hypocalcemia–hyperphosphatemia in patients with renal insufficiency. In chronic
situations, because of central nervous system toxicity associated with elevated
aluminum levels, it is preferable to treat hypocalcemia–hyperphosphatemia with
large doses of calcium carbonate (6 to 12 g per day) rather than with the standard
aluminum-containing antacids (227).
Approximately 20% of patients with renal insufficiency exhibit clinical
evidence of protein-calorie malnutrition. Vitamin deficiencies, most notably
with water-soluble vitamins, occur with dialysis. Nutritional disturbances in
patients with chronic renal insufficiency arise secondary to deficiencies in protein
intake, and studies show that, in patients with chronic renal insufficiency, their
kidneys are hyperfiltrating (228). Postoperatively, both protein and caloric intake
may need to be increased dramatically to meet catabolic demands in surgical
patients. As much as 1.5 g/kg of protein and 45 kcal/kg of calories may be needed
(228). Cardiovascular disease is very common in patients with chronic kidney
disease and complications are the leading cause of mortality in patients with
ESRD (229). Careful preoperative cardiovascular risk assessment should be done
for patients with ESRD with a focus on optimization preoperatively to reduce
cardiovascular events in the perioperative period.
Patients with chronic renal disease have an altered ability to excrete drugs and
are prone to significant metabolic derangements secondary to the altered
bioavailability of many commonly used medications. Because of this, and the
1394effect of dialysis on drug pharmacokinetics, the gynecologic surgeon and
nephrologist must be aware of the lowered metabolism and bioavailability of
narcotics, barbiturates, muscle relaxants, antibiotics, and other drugs that require
renal clearance. Pain control in the perioperative period can be achieved with a
variety of agents including acetaminophen, tramadol, and certain opiates. Nonopioids are always preferred, and acetaminophen can be used without dose
adjustment (230). Morphine should be avoided in patients with renal dysfunction
while fentanyl or hydromorphone can be used if opiates are necessary (230,231).
Liver Disease
Management of perioperative problems in gynecologic patients with liver disease
requires a comprehensive understanding of normal liver physiology and the
pathophysiology underlying diseases of the liver that may complicate surgery or
recovery. Patients with liver disease often have numerous complicated
problems involving nutrition, coagulation, wound healing, encephalopathy,
and infection.
Table 25-20 Child’s Classification of Liver Dysfunction
History and Physical Examination
Patients with a history of alcohol abuse, drug use, hepatitis, jaundice, blood
product exposure, or a family member with liver disease should undergo
biochemical evaluation. During the physical examination, note should be made
of any jaundice, signs of muscle wastage, ascites, right upper quadrant tenderness,
palmar erythema, or hepatomegaly.
Laboratory Testing
The biochemical profile (alkaline phosphatase, calcium, lactate dehydrogenase,
bilirubin, serum glutamic–oxaloacetic transaminase, cholesterol, uric acid,
phosphorous, albumin, total protein, and glucose) is not useful for routine
preoperative evaluation. Mild abnormalities can result in further extensive testing
1395that requires consultation, delays in surgery, and increased cost without net
benefit. A possible exception is selected use of biochemical testing when the
history or physical examination reveals abnormalities. Patients with known liver
disease should undergo albumin and bilirubin testing using the Child’s risk
classification (Table 25-20). This system was originally designed to predict
mortality following portosystemic shunt surgery. It divides patients into three
classes of severity based on five easily assessed clinical parameters. Measurement
of PT may be helpful in patients with significant histories of liver disease. If a
history of hepatitis is ascertained, the patient should be tested for serum
aminotransferase, alkaline phosphatase, bilirubin, albumin levels, and PT.
Serologic documentation of hepatitis is important.
Drug Metabolism
Patients with altered liver function should be carefully monitored because of
the prolonged action of many medications used during surgery. In addition to
impaired metabolism, hypoalbuminemia decreases drug binding, which alters
serum levels and biliary clearance rates. The degree of hepatic metabolism varies
greatly, depending on the type of medication considered.
Determination of Operative Risk
Although it is well known that acute hepatobiliary damage results in increased
morbidity and mortality in the surgical patient, estimating the operative risk in
patients with hepatic dysfunction is difficult based on the history and physical
examination. The most accurate method for risk assessment of surgery in
patients with hepatic dysfunction is Child’s classification (Table 25-20).
Using this system, accurate assessment of morbidity and mortality can be directly
related to the degree of liver dysfunction (232). The Child’s classification is
useful for patients undergoing a variety of different types of abdominal surgery.
Data show operative mortalities of 10%, 30%, and 82% for each of the three
Child’s classifications, respectively, while other data called this into question with
operative mortality of 2%, 12%, and 12% (233,234). The major cause of
perioperative death was often sepsis. This classification correlated significantly
with postoperative complications such as bleeding, renal failure, wound
dehiscence, and sepsis. Another method for determining operative risk in patients
with cirrhosis is the Model for End-Stage Liver Disease (MELD), which takes
into account the patient’s PT, bilirubin, and creatinine with various iterations used
to better predict perioperative morbidity and mortality (235). Originally designed
to predict outcomes in cirrhotic patients undergoing the transjugular intrahepatic
portosystemic shunt (TIPS) procedure, it was further studied to include patients
undergoing other surgical procedures. In patients with a MELD score greater than
139615, elective surgery should be deferred (236).
Acute Viral Hepatitis
Acute viral hepatitis poses an increased risk of operative complications and
perioperative mortality and is a contraindication for elective surgery (237).
Elective surgery should be delayed for approximately 1 month after the results of
all biochemical tests have returned to normal (238). In patients with ectopic
pregnancy, hemorrhage, or bowel obstruction secondary to malignancy, surgical
intervention must take place before normalization of serum transaminase levels
(237). In these situations, the perioperative morbidity (12%) and mortality (9.5%)
rates are much higher than when they are performed under ideal situations (239).
Chronic Hepatitis
Chronic hepatitis is a group of disorders characterized by inflammation of
the liver for at least 6 months. The disease is divided by morphologic and
clinical criteria into chronic persistent hepatitis and chronic active hepatitis. A
liver biopsy is usually required to establish the extent and type of injury. The
surgical risk in these patients correlates most closely with the severity of disease.
The risk of surgery in patients with asymptomatic or mild disease is minimal in
contrast to a significant risk for those patients who have symptomatic chronic
active hepatitis. Elective surgery is contraindicated in symptomatic patients, and
nonelective surgery is associated with significant morbidity (238).
Asymptomatic carriers of the hepatitis B virus (HBV; individuals who test
positive for the HBV surface antigen) are not at increased risk for
postoperative complications in the absence of elevated aminotransferase
levels and liver inflammation.
Alcoholic Liver Disease
Alcoholic liver disease encompasses a spectrum of diseases including fatty liver,
acute alcoholic hepatitis, and cirrhosis. Elective surgery is not contraindicated in
patients with fatty liver because liver function is preserved. If nutritional
deficiencies are discovered, they should be corrected before elective surgery.
Acute alcoholic hepatitis is characterized on biopsy by hepatocyte edema,
polymorphonuclear leukocyte infiltration, necrosis, and the presence of Mallory
bodies. Elective surgery in these patients is contraindicated (240). Abstinence
from alcohol for approximately 6 to 12 weeks along with clinical resolution of the
biochemical abnormalities are recommended before surgery is considered. Severe
alcoholic hepatitis may persist for several months despite abstinence and, if any
question of continued activity exists, a liver biopsy should be repeated (241). In
cases of urgent or emergent surgery on patients with alcohol dependence,
1397administration of tapered doses of benzodiazepine is appropriate as prophylaxis
against alcohol withdrawal.
Cirrhosis
Cirrhosis is an irreversible liver lesion characterized histologically by
parenchymal necrosis, nodular degeneration, fibrosis, and a disorganization of
hepatic lobular architecture. The most serious complication of cirrhosis is portal
venous hypertension, which ultimately leads to bleeding from esophageal varices,
ascites, and hepatic encephalopathy. Conventional liver biochemical test results
correlate poorly with the degree of liver impairment in patients with cirrhosis.
Hepatic dysfunction may be somewhat quantified by low albumin levels and
prolonged PTs.
Surgical risk is increased in patients with advanced liver disease, although
it is substantially greater in emergency surgery than in elective surgery.
Perioperative mortality correlates with the severity of cirrhosis and can be
estimated through the use of the Child’s classification (Table 25-20) and the
Model for End-Stage Liver Disease (MELD) score. In patients with Child’s class
A cirrhosis, surgery can usually be performed without significant risk, whereas in
patients with Child’s class B or C, surgery poses a major risk and requires careful
preoperative consideration. Preoperative preparation should include the following
measures: (i) optimizing nutritional status by enteral and parenteral nutrition and
supplementation with vitamin B1, (ii) correcting coagulopathy with
administration of FFP or cryoprecipitate or both, (iii) minimizing pre-existing
encephalopathy, (iv) preventing sepsis from spontaneous bacterial peritonitis by
administering prophylactic antibiotic therapy, and (v) optimizing renal function
and carefully correcting electrolyte abnormalities (242). Meticulous preoperative
preparation focused on correcting abnormalities associated with advanced liver
disease may improve surgical outcomes (243).
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