Lactic acidosis or propofol infusion syndrome

Described in pediatric and adult patients receiving prolonged high-dose infusions of propofol (>75 µg/kg per minute) for longer than 24 hours. Unexpected tachycardia occurring during propofol anesthesia should prompt a laboratory evaluation for possible metabolic (lactic) acidosis. A measurement of arterial blood gases and serum lactate concentrations is recommended. Metabolic acidosis in its early stages is reversible with discontinuation of propofol administration. The mechanism for sporadic propofol-induced metabolic acidosis is unclear but may reflect a poisoning (cytopathic hypoxia) of the electron transport chain and impaired oxidation of long-chain fatty acids by propofol or a propofol metabolite in uniquely susceptible patients. The differential diagnosis when propofol-induced lactic acidosis is suspected includes hyperchloremic metabolic acidosis associated with large volume infusions of 0.9% saline and metabolic acidosis associated with the excessive generation of organic acids, such as lactate and ketones (diabetic acidosis, release of a tourniquet).