每搏变异度监测胸腔镜手术患者单肺通气时血容量变化的准确性

Accuracy of stroke volume variation in monitoring blood volume during one-lung ventilation in patients undergoing thoracoscopy operation

目的 评价每搏变异度（SVV）监测胸腔镜手术患者单肺通气时血容量变化的准确性.方法 择期行胸腔镜手术患者22例,性别不限,年龄18～60岁,体重51～77 kg,ASA分级Ⅰ或Ⅱ级.麻醉诱导后置入双腔支气管导管,行双肺机械通气,进胸前改为单肺通气,通气参数：潮气量8 ml/kg,通气频率10～14次/min,吸呼比1∶2,氧浓度100%,PEEP 0,维持PETCO2 35～40 mm Hg.分别于双肺通气5 min和单肺通气30 min时进行容量负荷试验,于10 min内静脉输注6%羟乙基淀粉（HES）5 ml/kg.于双肺通气时输注HES前即刻和输注HES结束后3 min（T1.2）、单肺通气时输注HES前即刻和输注HES结束后3 min（T3.4）时,记录MAP、HR、CO、和SVV,计算CI及SVV和CI的变化率（△SVV和CI）.△CI≥11%为扩容有效,绘制SVV判断血容量变化的ROC曲线,计算曲线下面积（AUC）及其95%可信区间（95%CI）.结果 与输注HES前即刻比较,输注HES结束后CO升高,SVV降低（P＜0.05）.双肺通气时△SVV与△CI呈负相关,相关系数为-0.710（P＜0.05）.ROC曲线分析结果示：SVV监测血容量变化的阈值为11.5%,灵敏度为82%,特异度为92%,AUC为0.880（95%CI 0.580～0.987）.单肺通气时△SVV与△CI呈负相关,相关系数为-0.668（P＜0.05）.ROC曲线分析结果示：SVV监测血容量变化的阈值为9.5%,灵敏度为77%,特异度为63%,AUC为0.971（95%CI 0.917～1.024）.结论 单肺通气并不会影响SVV监测胸腔镜手术患者血容量变化的准确性.

Objective To evaluate the accuracy of stroke volume variation （SVV） in monitoring blood volume during one-lung ventilation in patients undergoing thoracoscopy operation. Methods Twenty-two ASA Ⅰ or Ⅱ patients （ 12 male, 10 female） aged 18-60 yr undergoing thoracoscopy operation under general anesthesia were studied. Anesthesia was induced with midazolam, sufentanil, propofol and rocuronium and maintained with TCI of propofol and remifentanil and intermittent iv boluses of vecoronium. Robertshow double-lumen endobronchial tube was inserted. Correct position of the tube was verified by fiberoptic bronchoscopy. The patients were mechani40 mm Hg. Radial artery was cannulated and connected to FloTrac pressure transducer and Vigileo monitor. A loading dose of 6% HES 5 ml/kg was infused over 10 min. MAP, HR, CO and SVV were recorded before and at 3 min after loading dose. The change rate of SVV （SVV） and CI （△CI） were calculated. Increase in CI by 11% was considered effective volume expansion. The ROC curve for SVV in determining the volume expansion efficacy was plotted. The area under the curve for SVV and 95% confidence interval were calculated. Results （1） CO were significantly increased while SVV decreased after a loading dose of HES. （2） During two-lung ventilation 12 patients responded to the 6% HES loading dose.SVV correlated with△CI （ - 0.710, P 〈 0.05）. The volume expansion efficacy was determined by SVV 11.5 % （sensitivity = 82 %, specificity = 92 % ）. The area under the curve for SVV and 95% confidance interval were 0.880 （0.580-0.987）. （3） During one-lung ventilation 11 patients responded to the 6 % HES loading dose. SVV correlated with CI （ - 0.668 , P 〈 0.05）. The volume expansion efficacy was determined by SVV 9.5 % （ sensitivity = 77 %, specificity = 63 % ）. The area under the curve for SVV and 95% confidance interval were 0.971 （0.917-1.024）. Conclusion One-lung ventilation does not alter the ability of SVV in monitoring blood volume in patients undergoing thoracoscopy operation.