Propofol related infusion syndrome is a rare complication firstly reported in paediatric patients and also observed in adults, produced due to prolonged (>48 h) high doses of propofol (>66 mcg/kg/min) intravenous infusion.
Even short-term propofol related infusion syndrome for surgical anaesthesia have been associated with development of metabolic acidosis. Propofol related infusion syndrome is characterized by myocardial failure, metabolic acidosis and rhabdomyolysis.
Hyperkalaemia, lipaemia and renal failure have also been associated with this syndrome. Unexpected tachycardia occurring during propofol anaesthesia should prompt laboratory evaluation for possible metabolic (lactic) acidosis.
Risk factors for propofol infusion syndrome in adults include lean body mass index, high dose, and administration of more than 24-hour duration. The patients who develop this propofol related infusion syndrome mostly suffer from acute neurological illnesses or acute inflammatory diseases complicated by severe infections or even sepsis, and receiving catecholamines and/or steroids in addition to propofol.
Creatine phosphokinase, lactic acid levels, electrolytes, and arterial blood gases should be monitored frequently. Metabolic acidosis in its early stages is reversible with discontinuation of propofol administration. To increase elimination of propofol related infusion syndrome and its potential toxic metabolites, haemodialysis or haemofiltration are recommended.
The mechanism for sporadic propofol induced metabolic acidosis is unclear. It has been assumed that the pathophysiologic cause is propofol’s impairment of oxidation of fatty acid chains and inhibition of oxidative phosphorylation in the mitochondria, leading to lactate acidosis and muscular necrosis.
It has been postulated that propofol might act as a trigger substrate in the presence of priming factors. Severe diseases in which the patient has been exposed to high catecholamine and cortisol levels or systemic inflammation with cytokine production are priming factors for cardiac and peripheral muscle dysfunction.