经皮穴位电刺激复合药物全麻行控制性降压至不同水平对肝血流的影响

目的探讨经皮穴位电刺激(transcutaneous electrical acupoint stimulation,TEAS)复合药物全麻行控制性降压至不同水平的肝血流变化,从而明确针药复合麻醉的肝保护效应机制。方法 42只雄性比格犬随机分为7组:单纯全麻组、50%对照组、50%实验组、40%对照组、40%实验组、30%对照组和30%实验组,每组6只,后6组动物均以异氟醚联合硝普钠行控制性降压,将动脉血压降至50%、40%、30%基础平均动脉血压(mean arterial pressure,MAP)水平并维持60min,单纯全麻组不行控制性降压。实验组采用TEAS干预处理,刺激强度(4±1)mA,频率2/100Hz,穴位选用犬双侧"合谷(LI4)"、"足三里(ST36)"、"三阴交(SP6)"、"曲池(LI11)",电刺激在动物生理状态稳定后开始至维持目标MAP60min后停止。采用激光多普勒组织血流仪监测不同水平相应时间点肝组织表面血流的变化。结果在控制性降压开始至目标低血压维持结束,50%对照组肝血流在各时间点均显著低于同期单纯全麻组和基础水平(P<0.05),而50%实验组仅在维持30～60min阶段显著降低,且在维持阶段早期(10～30min),50%实验组肝血流显著高于同期对照组(P<0.05),而40%、30%各水平实验组肝血流无明显升高。在血压回升阶段(20～30min),40%实验组肝血流已先后恢复到同期单纯全麻组水平和基础水平,而对照组尚未恢复;在此阶段,50%、30%实验组和对照组肝血流有相似的变化趋势。结论在行控制性降压至50%水平时,TEAS的肝保护效应在降压、维持阶段早期体现明显。在行控制性降压至40%时,TEAS的肝保护效应在血压回升阶段体现明显。

Effects of Transcutaneous Electrical Acupoint Stimulation Combined General Anesthesia in Controlled Hypotension at Different Levels on the Liver Blood Flow

Objective To observe the changes of the liver blood flow in controlled hypotension by transcutaneous electrical acupoint stimulation(TEAS) combined general anesthesia,thus clarifying the mechanism of liver protection effect in acupuncture anesthesia combined with drugs.Methods Forty-two male beagles were randomly divided into seven groups,i.e.,the general anesthesia group,the 50% control group,the 50% experiment group,the 40% control group,the 40% experiment group,the 30% control group,and the 30% experiment group,6 in each group.Beagles in the latter six groups were administered with isoflurane inhalation and intravenous dripping of sodium nitroprusside(SNP) for controlled hypotension.The mean arterial pressure(MAP) was lowered to 50%,40%,and 30% basic MAP and lasted for 60 min.Beagles in the general anesthesia group was not treated with controlled hypotension.In the experiment groups,TEAS was applied to bilateral Hegu(LI4),Zusanli(ST36),Sanyinjiao(SP6),and Quchi(LI11) at 2/100 Hz with the stimulation strength of 4±1 mA.The TEAS started from the stability of physiological conditions to 60 min after maintaining the target MAP.The changes of blood flow of the liver tissue surface at corresponding time points were monitored by laser Doppler blood flow meter.Results Between the beginning of hypotension and the maintaining stage of target low blood pressure,the liver blood flow of the 50% control group was significantly lower than the level of the general anesthesia group and the basic level at corresponding time points(P<0.05).It was significantly reduced in the 50% experiment group only at 30-60 min of maintenance.Besides,in the early period of maintenance(10-30 min),it was significantly higher in the 50% experiment group than in the 50% control group at the same time points(P<0.05).In this stage,there was no obvious increase in the liver blood flow in the 40% and 30% experiment groups.In the recovery phase of blood pressure(20-30 min),the liver blood flow of the 40% experiment group had been restored to the level of the 40% control group and the basic level,while it had not been restored in the general anesthesia group.In this stage,the similar changing tendency of the liver blood flow occurred in the 50% and 30% experiment groups and the 50% and 30% control groups.Conclusions Line to a high level of controlled hypotension(50%),TEAS liver protective effect was obviously embodied in the early step-down phase and the maintenance phase.Line-induced hypotension to a lower level(40%),TEAS liver protective effect was obviously embodied in the recovery phase.