Pharmacokinetics of propofol administered by target-controlled infusion in patients with liver failure

Objective To investigate pharmacokinetics of propofol administered by target-controlled infusion (TCI) in patients with liver failure. Methods Nine ASA Ⅳ patients with liver failure aged 32-53 years,weighing 60-81 kg,who would undergo liver transplantation,were enrolled in this study,and nine ASA Ⅰ-Ⅱ patients aged 22-59 years,weighing 46-70 kg,who would undergo selective upper abdominal surgery,were as control group. In the two groups,propofol was administered for 60 min by TCI via Graseby 3500 infusion pump incorporated with Stelpump software,while the target plasma propofol concentration was set at 2.5 μg/ml. Arterial blood samples were taken immediately before and at 2,5,10,20,30,40,50,60,62.5,65,70,75,80,85,90 min after the start of propofol infusion,and the plasma concentrations of propofol were measured by using gas chromatography-mass spectrometry. The data obtained were analyzed by DAS pharmacokinetic software. Results The central volume of distribution (Vc),apparent volume of distribution (Vp) and total clearance (CL) were significantly larger in liver transplantation group than those in control group (P0.05),but no significant differences in distribution half-time (T1/2α),elimination half-time (T1/2β) were found between the two groups. Conclusion The volume of distribution and clearance of propofol increased in the patients with liver failure,which will not lead to drug accumulation and long duration of action.