异氟醚反馈吸入麻醉用于肥胖病人的可行性

Application of isoflurane feedback inhalation anesthesia in obese patients

目的研究应用脑电双频谱指数(BIS)监测反馈调控异氟醚吸入麻醉干肥胖病人的可行性。方法将40例择期肥胖手术病人随机分为对照组(组Ⅰ)和BIS反馈组(组Ⅱ),每组20例。组Ⅰ术中麻醉深度以MAP.HR和对手术刺激的反应为依据调节麻醉深度。组Ⅱ以BIS值作为控制变量,"吸入麻醉执行者"以比例—积分—微分(PID)控制运算法则对目标BIS值与实测值进行处理,然后按照TCI-I泵预先设定的命令格式每2s输出新的命令至TCI泵,调节异氟醚至呼吸环路的液量。观察全麻诱导插管期,维持期及恢复期的血液动力学变化,并记录术毕停药后两组病人意识恢复时间(睁眼和拔管时间),随访有否术中知晓。结果麻醉诱导后两组病人的BIS值较基础值明显为低(P<0.01),术中两组病人的BIS值差别不显著(P>0.05)。两组BIS高于60的发生率分别为14.03%和7.48%,差异具有显著性P<0.05。两组BIS低于40的发生率分别为1.75%和1.21%,差异无显著性(P>0.05)。术毕唤醒时间组Ⅱ早于组Ⅰ(P<0.05);术后随访病人均无术中知晓。结论应用BIS值反馈调控吸入麻醉,可更加合理地评估麻醉深度,防止术中知晓,减少麻醉用药量,加快病人苏醒。

Objective： To study the feasibility of application of bispectral index （BIS） feedback in control of inhalation anesthesia in obese patients. Methods： Forty patients were randomly divided into the control group （group Ⅰ） and the BIS feedback group （group Ⅱ） with 20 in each group. In group Ⅰ, anesthesia depth adjusting was based on MAP, HR and the reaction of operation stimulation. In group Ⅱ using BIS as the control variable, a closed - loop anesthesia system was built using a proportional - integral - differential incorporated with adaptive control algorithm, and with a target - controlled infusion system as the control actuator, closed - loop performance dealt with changing of BIS both target and reality measure, and then according to the order in the TCI-Ⅰ pump presetted pattern, new orders were given to TCI pump to adjust liquid of Isoflurane which reached respiratory circuit. Hemodynamic change was observed in the induction of anesthesia, placement of endobronchial tube, maintaining of total anesthesia and the convalescent. The consciousness recovery time was recorded after stopping inhalating Isoflurane （opening eyes and extubation time） , and patients＇awareness was checked during operation. Results： After induction of anesthesia, BIS count of two groups was significantly different （P 〈 0. 01 ） ; during operation BIS count of patients had no significant difference （ P 〉 0.05 ）. The incidence rate of BIS count over 60 ： in group Ⅰ at 14.03%, and group Ⅱ at 7.48%, which showed significant difference （ P 〈 0.05 ）, and the incidence rate of BIS count below 40： in group Ⅰ at 1. 75 %, and in group Ⅱ at 1.21%, which showed no significant difference（ P 〉 0.05 ） . The time of patients＇ awakening in group Ⅱ was earlier than that in group 1 at the end of operation （ P 〈 0.05 ）. AII patients had no awareness during operation . Conclusion： It may be more proper with inhalation general anesthesia to apply BIS feedback controls of anesthesia depth to obese patients to prevent from awareness during operation, to decrease the doses of anesthetics and to accelerate consciousness recovery.