Case 21: Postoperative confusion

 

Case 21: Postoperative confusion

CASE 21: POSTOPERATIVE CONFUSION

History

You are on call in the early evening and are asked to see a woman in the day surgery unit

who is confused postoperatively. She is 42 years old and underwent transcervical resection of

multiple submucosal fibroids in the early afternoon after presenting with menorrhagia. Four

fibroids were resected and the estimated blood loss was 150 mL.

Examination

The woman knows her name but is disorientated, scoring only 5/10 on a mini-mental state

examination. She seems slightly drowsy. The heart rate is 100/min and the blood pressure is

105/70 mmHg. Oxygen saturation is 94 per cent on air. She is apyrexial. Chest examination

reveals dullness at both bases with fine inspiratory crackles. The abdomen is not distended

but there is generalized lower abdominal tenderness. No masses are palpable and there are

no signs of peritonism. You can see that there is small amount of blood from the vagina, but

the loss is not excessive. You are told that she passed urine an hour ago without difficulty.

The operation note is reviewed and you find that the procedure was essentially uncomplicated but was halted before all the fibroids could be fully resected because of the fluid imbalance. The fluid deficit is recorded as 1010 mL. However you review the actual fluid chart and

it is as follows:

Fluid input (glycine, via operating hysteroscope input channel):

1000 mL; 1000 mL; 1000 mL; 950 mL

Fluid output (via operating hysteroscope output channel): 1940 mL

INVESTIGATIONS

Normal range

Haemoglobin 10.4 g/dL 11.7–15.7 g/dL

Haematocrit 29% 36–58%

White cell count 7.1×109/L 3.5–11×109/L

Platelets 302×109/L 150–440×109/L

Sodium 129 mmol/L 135–145 mmol/L

Potassium 3.1 mmol/L 3.5–5 mmol/L

Urea 1.6 mmol/L 2.5–6.7 mmol/L

Creatinine 56 mmol/L 70–120 mmol/L

The chest X-ray is shown in Fig. 21.1.

Questions

• What is the diagnosis

and why has it occurred?

• How would you manage

this patient?

Figure 21.1

Chest X-ray.100 Cases in Obstetrics and Gynaecology

50

ANSWER 21

The chest examination and X-ray suggest pulmonary oedema. Investigations show hyponatraemia and this is a recognized cause of a confusional state. There is also hypokalaemia

which puts her at risk of dysrhythmia or cardiac arrest.

There has been an error in calculating the fluid deficit such that the deficit is in fact 2010 mL

rather than 1010 mL. The hyponatraemia is therefore caused by fluid overload, a recognized

complication of transcervical resection procedures. The normal upper limit for the procedure is 1000 mL and in this case twice that volume has been absorbed.

Management

The mainstay of management is supportive with monitoring of electrolytes and fluid restriction. Potassium supplementation should be given and electrocardiogram (ECG) monitoring

employed until the potassium is normal.

The woman should be transferred to a high-dependency bed and given oxygen. Arterial

blood gas should be monitored, and if the pulmonary oedema worsens then diuretics will

be needed.

The hyponatraemia usually corrects itself with time and fluid restriction, and the acute confusional state would be expected to resolve as the electrolytes normalize.

The fibroids were not completely resected and a repeat ultrasound or outpatient hysteroscopy

may be considered after a few weeks to check whether further surgery is needed – sometimes degeneration may occur as a result of thermal damage or inflammation from the initial

procedure. Alternatively any fibroid remnants may be expelled spontaneously through the

cervix and vagina.

KEY POINTS

• Fluid overload and consequent hyponatraemia is a recognized complication of

transcervical resection procedures.

• Accurate input/output monitoring is vital during this procedure.

• Treatment is supportive until electrolytes return to normal.