恒速静脉输注异丙酚时脑摄取的研究

The cerebral uptake of propofol during continued infusion at a constant rate

目的 研究恒速静脉输注异丙酚时脑摄取与输注速率、输注时间的关系。方法 14例ASAⅠ～Ⅱ级择期手术患者 ,随机分为A、B两组 ,恒速静脉输注异丙酚的速率分别为 6、12mg·kg-1·h-1,持续 30～ 35min。于给药后不同时点同步采取桡动脉及颈内静脉球部血样 ,以高效液相色谱 荧光法检测异丙酚的血药浓度。结果 恒速静脉输注异丙酚起始 15min ,两组桡动脉血药浓度 (Ca)随时间逐渐升高 ,15min后维持恒定不变 ;A组颈内静脉球部血药浓度 (Cijbv)静注异丙酚 30min期间随时间升高 ,但低于相应Ca(P <0 0 5 ) ,30～ 35min时维持恒定 ,并接近于Ca;而B组Cijbv静注异丙酚2 0min期间随时间升高 ,但低于相应Ca(P <0 0 5 ) ,2 0～ 30min时维持恒定 ,并接近于Ca;脑摄取达稳态前各时点累积桡动脉、颈内静脉球部血药浓度 时间曲线下累积面积差 (AUCa v)组间差异显著 (P <0 0 5 )。结论 恒速静脉输注异丙酚麻醉脑摄取达平衡前 ,异丙酚摄取量呈速率和时间依赖性。异丙酚脑摄取动态平衡滞后于动脉血药浓度的平衡。

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.