Pharmacokinetic Profile of the Induction Dose of Propofol in Patients with Severe Burns

The pharmacokinetics of propofol were studied in nine severely burnt patients undergoing general anaesthesia with enflurane/fentanyl for escarectomy. All patients received an intravenous bolus dose of propofol 2 mg/kg, and blood concentrations of propofol were measured over the subsequent 12 hours using high performance liquid chromatography with fluorescent detection. Propofol blood concentrations, showing a very rapid initial decline and a long terminal elimination phase, were best fitted by a triexponential function describing a 3-compartment open mamillary model with rapid distribution from the central compartment, extensive redistribution and elimination from the central compartment. When compared with nonburnt normal controls, the patients with burns showed lower propofol blood concentrations, lower baseline albumin blood levels (p ≤ 0.001), smaller areas under the concentration-time curve (p ≤ 0.001), larger volumes of distribution (p ≤ 0.001), and higher total body clearance (p ≤ 0.001). Pathophysiological systemic responses to the burn injury and particularly the presence of oedema and changes in albumin concentrations were probably responsible for the significant alterations in the disposition kinetics of propofol in the patients with burns.