A mechanically ventilated ICU patient receiving propofol infusion at 5 mg/kg/h for 72 hours develops new-onset metabolic acidosis (pH 7.18, lactate 8 mmol/L), lipemic plasma, rhabdomyolysis, and bradycardia. What is the diagnosis and management?

• A Propofol overdose requiring flumazenil reversal
• B Septic shock with multi-organ failure unrelated to propofol
• C Thiamine deficiency causing Wernicke's encephalopathy — administer high-dose thiamine
• D Propofol infusion syndrome (PRIS) — stop propofol immediately, supportive care, consider haemodialysis ✓

Explanation

Propofol infusion syndrome (PRIS) is a life-threatening complication occurring with high-dose (>4 mg/kg/h) or prolonged propofol infusion, particularly in critically ill patients. The hallmark features are: severe metabolic acidosis (high lactate), lipaemia, rhabdomyolysis, myoglobinuria, cardiac failure (new BBB, ST changes), and renal failure. The mechanism involves impaired mitochondrial electron transport chain function and fatty acid oxidation. Management: immediate cessation of propofol, switch to alternative sedation, aggressive supportive care, haemodialysis for refractory acidosis/renal failure. ICU doses should not exceed 4 mg/kg/h for >48 hours.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.