侧卧位开胸手术对每搏量变异度的影响

目的 比较左侧卧位和右侧卧位开胸手术对每搏量变异度(SVV)和血流动力学的影响.方法 选择40例择期行开胸手术的患者,美国麻醉医师学会(ASA)分级Ⅰ～Ⅱ级,分为左侧卧位和右侧卧位组(各20例).两组术前30 min肌内注射阿托品0.5 mg、苯巴比妥钠0.1 g,入室后吸氧5 L/min,行动静脉穿刺,应用多功能监测仪连续监测心电图、心率(HR)、脉搏血氧饱和度(SpO_2)和平均动脉压(MAP).应用Vigileo持续心排出量监测仪持续监测SVV、心排出量(CO)和每搏量(SV).安静平卧10 min后(T_1),进行全身麻醉诱导,待肌颤消失后经口腔明视插入双腔支气管导管,接呼吸机双肺通气,监测呼气末二氧化碳分压(P_(ET)CO_2),静脉注射维库溴铵4～6 mg,采用异氟烷0.8～1.0最小有效肺泡浓度(MAC)维持麻醉,稳定10 min后(T_2),转侧卧位后再稳定10 min(T_3)开始手术.进胸后行单肺通气,记录时间点为单肺通气10 min(T_4)、30 min(T_5)和60 min(T_6).结果 侧卧位T_3时间点的SVV均显著低于平卧位T_2时间点的水平(P值均<0.05).开胸单肺通气过程中,SVV相对比较平稳,T_4、T_5和T_6时间点间的差异无统计学意义(P值均>0.05).两组T_2、T_3时间点的CO、MAP和SV均较T_1时间点显著下降(P值均<0.05).开胸单肺通气过程中,T_4时间点(开始阶段)的CO、MAP和SV与T_1时间点的差异均无统计学意义(P值均>0.05),在随后的T_5、T_6时间点,CO、MAP和SV出现下降,显著低于T_1时间点(P值均<0.05).左侧卧位与右侧卧位组间在各时间点的SVV的差异均无统计学意义(P值均>0.05).结论 开胸手术左侧卧位与右侧卧位对循环功能和血容量状态的影响无显著区别.

Effect of lateral position during thoracotomy on stroke volume variation

Objective To compare the effects of left and right lateral positions during thoracotomy on the stroke volume variation and circulation function.Methods Forty patients of American Society of Anesthesiologists (ASA)class Ⅰ orⅡ,who were scheduled for open chest operation,were evenly divided into left-lateral position group and right-lateral position group.All patients received atropine 0.5 mg and phenobarbital sodium 0.1 g(i.m.)30 min before anesthesia.After patients entered operation room,nasal oxygen inhalation and arteriopuncture with A-line and with Ⅳ cathether venipuncture were performed.The electrocardiogram(ECG),heart rate(HR),pulse oxygen saturation(SpO_2)and mean arterial pressure(MAP)were monitored with S/5 monitor multifunction monitoring equipment.The cardiac output(CO),stroke volume(SV)and stroke volume variation(SVV)were measured through arterial pressure waveform analysis by Vigileo cardiac output monitor.After the patients rested for 10 rain(T_1),general anesthesia was induced with midazolam(2 mg),fentanyl(2 μg/kg),propofol(1-2 mg/kg)and succinylcholine(1.5 mg/kg).The patients were endotracheally intubated with Robertshow double lumen endobronchial tubes(DLT).Vecuronium 4-6 mg(i.v.)and isoflurane 0.8-1.0 MAC in oxygen were administered to maintain anesthesia.After 10 min(T_2),the patients were positioned from supine to lateral position.Ten minutes later(T_3),the operation began.When the chest was opened,one-lung ventilation(OLV)was performed.Heart rate(HR),mean arterial pressure(MAP),stroke volume(SV),stroke volume variation (SVV)and cardiac output(CO)were recorded at T_1,T_2,T_3 and after 10 min(T_4),30 min(T_5)and 60 min(T_6)of OLV.Results The SVV decreased after changing the position to lateral,(P<0.05).SVV had no significant change during OLV(T_4,T_5 and T_6)(P>0.05).After induction and endotracheal intubation,CO,MAP and SVwere significantly decreased (P<0.05). After the posture was changed to lateral, CO, MAP and SV were lower than those before anesthesia(P<0.05). After 10 min OLV (T_4), CO, MAP and SV had no significant changes compared with those before anesthesia ( P> 0.05) ;these parameters decreased gradually thereafter (T_5, T_6 ),and became lower than those before anesthesia (P<0.05). SVV, CO, MAP, SV and HR were similar between two position groups at all five time points(P>0.05). Conclusion Left-lateral position and right-lateral position have no significant effects on the circulation function and blood volume state in patients undergoing intra-thoracic operation.