The cerebral uptake of propofol during continued infusion at a constant rate / 中华麻醉学杂志

ABSTRACT

Objective To study the rate and time-course of the cerebral uptake of propofol during the intravenous continued infusion at a constant rate.Methods Fourteen adult patients were randomly assigned to receive a propofol infusion at a constant of 6 mg?kg -1?h -1(group A) or 12 mg?kg -1?h -1 (group B) for 30-35 min. Blood samples were taken simultaneously from radial artery and jugular venous bulb for measurement of propofol concentrations by high performance liquid chromatography.Results The arterial propofol concentrations(C a) increased progressively during the first 15min after the start of propofol infusion and became stable 15min later.Jugular bulb venous blood propofol concentrations(C ijbv) were increased progressively during the first 30min after the start of propofol infusion in group A and the first 20min in group B, but they were lower than C a at the corresponding interval. 30min after the start of propofol infusion in group A and 20min in group B C ijbv became stable and close to C a. There was significant difference in the accumulated area between the arterial and jugular bulb venous concentration-time curves at the different interval between the two groups before the equilibrium of cerebral uptake was achieved.Conclusions Cerebral propofol uptake is rate- and time-dependent when administered at a constant infusion rate, and there is a hysteresis between the arterial blood concentration and equilibrium of cerebral uptake. Propofol is not metabolized in human brain.