Pregnant and nil by mouth

A 36 year old woman who was 29 weeks pregnant (gravida 5 para 4) presented with pain in her abdomen and right flank. She denied any dysuria or urinary frequency, but complained of several episodes of vomiting and had taken no oral fluids at home. She was afebrile.

She had an ultrasound scan of her abdomen, which showed cholelithiasis and a gallstone impacted in the gallbladder neck. She was started on intravenous antibiotics. External cardiotocography of the fetus was unremarkable.

She was still not tolerating anything orally, so intravenous fluids were initiated. Over the next few days of her admission, she required frequent reviews for an intermittent high respiratory rate. She was not hypoxic and remained haemodynamically stable during these reviews. A pulmonary embolus was excluded with a ventilation perfusion scan. On her fourth day of admission she was scheduled for a cholecystectomy. The night before she was due in theatre, an urgent review was required for an increased respiratory rate with normal saturations on room air and tachycardia. An arterial blood gas showed pH 7.14, pCO₂ 1.8 kPa, HCO₃ 9 mmol/L, pO₂ 17.9 kPa, K+4.2 mmol/L, Na 132 mmol/L, Cl⁻ 105 mmol/L (normal range 98-106 mmol/L), lactate 0.4 mmol/L (0.5-1 mmol/L), and glucose 4.3 mmol/L …