Propofol infusion syndrome (PRIS) is a rare but lethal complication of prolonged high-dose propofol infusion. The pathophysiology involves:

• A Precipitation of propofol crystals in renal tubules causing acute tubular necrosis
• B Immune-mediated myocarditis triggered by the phenol nucleus
• C Accumulation of phenol metabolites causing methemoglobinemia
• D Uncoupling of mitochondrial oxidative phosphorylation and impaired fatty acid oxidation ✓

Explanation

PRIS is characterised by severe metabolic acidosis, rhabdomyolysis, cardiac failure (right bundle branch block, ST elevation), hypertriglyceridaemia, and renal failure. The central mechanism is disruption of mitochondrial electron transport chain (complexes II and IV) and impairment of fatty acid beta-oxidation, causing cellular energy failure. Risk factors include doses >4 mg/kg/h for >48 hours, concurrent catecholamine or steroid use, and carbohydrate depletion. Crystal precipitation and immune myocarditis are not the mechanisms.

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

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Written and medically reviewed by the StethoPrep medical team.