不同靶控浓度反馈输注异丙酚的药效动力学

The clinical effects of different target concentrations during closed-loop anesthesia with propofol administered by TCI

目的 探讨靶控反馈输注异丙酚的浓度与临床效应的关系,寻求最佳靶控浓度。方法24例ASA Ⅰ～Ⅱ级拟行腹腔镜胆囊切除术(LC)的患者,随机分成三组,每组8例。术中行异丙酚反馈靶控输注。三组靶浓度分别为3.0 μg/ml(A组)、3.5μg/ml(B组)、4.0μg/ml(C组)。术中监测血压(BP)、平均动脉压(MAP)、心率(HR)、脑电双频指数(BIS)。分别于诱导前、异丙酚输注后1、2、3、4、5min、插管后、10、15、20、30、40 min、唤醒时、拔管时抽取桡动脉血,采用反向高效液相色谱分析法测定血药浓度。结果 麻醉诱导期间,A组BIS下降与B组、C组差异有显著性(P<0.05)。各组异丙酚诱导剂量差异均有显著性(P<0.05)。麻醉维持期间,A组用药量少于B组和C组(P<0.05)。B组与C组之间差异无显著性(p>0.05)。A组MAP、HR的波动明显大于B组、C组(P<0.05)。麻醉诱导期C组患者的MAP下降幅度大于B组(P<0.05)。各点实测血药浓度(Cm)低于预测血药浓度(Cp)。B组Cm、Cp的曲线波动均较C组小。三组BIS与Cp均良好负相关。结论 在LC术中3.5μg/m1靶控浓度为异丙酚靶控反馈输注静脉麻醉的推荐浓度。

Objective During TCI of propofol anesthesiologist still has to rely on depth of anesthesia and blood pressure (BP) to alter the target concentration. In this study depth of anesthesia was monitored by BIS and TCI was controlled by feedback from BP and BIS monitoring. The purpose of this study was to determine the best target concentration during closed-loop anesthesia with propofol administered by TCI in terms of cardiovascular stability.Methods Twenty-four ASA I -II patients (12 male, 12 female) aged 20-50 years weighing 45-70 kg presenting for laparoscopic cholecystectomy were randomly divided into 3 groups of eight patients according to target concentration of propofol entered into the TCI system : group A 3 .0μg·ml-1 ; group B 3.5μg·ml-1 and group C 4.0μg·ml-1 . The patients were premedicated with intramuscular atropine 0.5mg and phenobarbital 0.1g. Propofol was administered by Graseby 3 500 which was connected to BIS and BP monitor (HXD-1) via RS 232 connector. Anesthesia was induced with fentanyl 5 μg·kg-1 and propofol given by TCI. Intubation was facilitated with vecuronium 0.1 mg##kg-1 when patients lost consciousness. During maintenance of anesthesia TCI of propofol was controlled by feedback from BIS and BP monitoring. Propofol infusion was stopped whenever BIS was < 50 or MAP < 80% of the baseline value and restarted when BIS > 50 or MAP > 80% of the baseline value. Radial artery was cannulated for direct BP monitoring. BP, HR, SpO2 and BIS were monitored throughout anesthesia. Blood samples were taken from radial artery for determination of blood propofol concentration before induction of anesthesia, 1, 2, 3, 4, 5 min after TCI of propofol was started, 10, 20, 30 rnin after intubation, when patient regained consciousness and at extubation. Results During induction of anesthesia the decrease in BIS was significantly less in group A than that in group B and C (P < 0.05). The amount of propofol infused for induction was significantly different among the three groups ( P < 0.05). During maintenance of anesthesia the propofol dose was significantly less in group A than that in group B and C ( P < 0.05) . The fluctuation in MAP and HR was significantly greater in group A than in group B and C ( P < 0.05). During induction of anesthesia the magnitude of decrease in MAP was significantly greater in group C than that in group B ( P < 0.05) . The measured blood propofol concentrations were lower than the predicted concentrations at all time points after start of TCI. There was a close negative correlation between BIS and predicted target concentration. Conclusion 3.5 μg·ml-1 is the appropriate target concentration needed with TCI of propofol administered by Graseby 3500 for laparoscopic cholecystectomy.