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摘要：
目的 评价肺复张诱导主动脉瓣速度时间积分（velocity time integral, VTI）变化评估肺保护性通气患者容量反应性的准确性。 方法 择期全麻下行胃肠手术的患者45例，年龄50~70岁，ASA分级Ⅰ、Ⅱ级，左室射血分数（left ventricular ejection fractions, LVEF）>55%。所有患者全麻诱导气管插管后行肺保护性通气［潮气量7 ml/kg，呼气末正压（positive end expiratory pressure, PEEP）5 cmH2O（1 cmH2O=0.098 kPa）通气，FIO2 60%］，待血流动力学平稳后，给予一次肺复张（lung recruitment maneuver, RM）。于心尖五腔心切面，将脉冲多普勒取样点置于距主动脉瓣1 cm之内，描记VTI。记录RM前后VTI、MAP和心率，并计算速度时间积分变异度（velocity time integral variation, △VTI）、平均动脉压变异度（mean arterial pressure variation, △MAP）和心率变异度（heart rate variation, △HR）。暂将潮气量改为9 ml/kg并连接Vigileo系统后行容量负荷试验（volume expansion, VE），记录容量负荷试验前后每搏量（stroke volume, SV），并计算每搏量变异率（stroke volume variation, △SV）。依据△SV将患者分为两组：有反应组（R组，△SV≥15%，26例）和无反应组（N组，△SV<15%，19例）。采用受试者工作特征（receiver operating characteristic, ROC）曲线对△VTI、△MAP和△HR进行分析，并计算最佳Youden指数时各指标值，评价RM诱导△VTI评估肺保护性通气患者容量反应性的准确性。 结果 与RM前比较，两组患者RM后MAP、VTI均明显下降（P<0.05）；两组患者RM前后心率差异无统计学意义（P>0.05）。与N组比较，R组△HR升高（P<0.05），△MAP和△VTI降低（P<0.05）。ROC曲线分析结果示：△VTI预测肺保护性通气患者容量反应性阳性的诊断阈值为18.065%，灵敏度为92.3%，特异度为73.7%，曲线下面积（area under curve, AUC）为0.893（95%CI 0.800~0.986，P<0.05）；△MAP预测肺保护性通气患者容量反应性阳性的诊断阈值为11.120%，灵敏度为73.1%，特异度为84.2%，AUC为0.864（95%CI 0.762~0.967，P<0.05）；△HR预测肺保护性通气患者容量反应性阳性的诊断阈值为1.575%，灵敏度为69.2%，特异度为52.6%，AUC为0.596（95%CI 0.427~0.765，P>0.05）。 结论 RM诱导的△VTI可准确评估肺保护性通气患者容量反应性，当Youden指数最佳时，△VTI诊断阈值为18.065%，敏感度为92.3%，特异度为73.7%。
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Abstract: Objective To evaluate the accuracy of changes in aortic valve velocity time integral (VTI) induced by lung recruitment maneuver for evaluating fluid responsiveness in patients with lung-protective ventilation. Methods A total of 45 patients, aged 50 to 70 years, American Society of Anesthesiologists (ASA) class Ⅰ or Ⅱ, with>55% left ventricular ejection fractions (LVEF), who underwent elective gastrointestinal surgery under general anesthesia were enrolled. After tracheal intubation under general anesthesia, all the patients underwent lung-protective ventilation [tidal volume 7 ml/kg, positive end expiratory pressure (PEEP) 5 cmH2O (1 cmH2O=0.098 kPa), and FiO2 60%]. When hemodynamics became stable, single lung recruitment maneuver (RM) was performed. In the apical five chamber view, the pulse Doppler sampling point was placed within 1 cm of the aortic valve to record the aortic valve VTI. Furthermore, VTI, MAP and heart rate were recorded before and after lung recruitment maneuver, and velocity time integral variation (△VTI), mean arterial pressure variation (△MAP), and heart rate variation (△HR) were calculated. Then, the tidal volume was changed to 9 ml/kg and the Vigileo system was collected to perform the volume expansion (VE) test. The stroke volume (SV) was recorded before and after the VE test and stroke volume variation (△SV) was calculated. According to △SV, the patients were divided into two groups: a response group (group R, △SV≥15%, n=26) and a non-response group (group N, △SV<15%, n=19). A receiver operating characteristic curve was plotted to analyze the △VTI, △MAP and △HR, and each indicator was calculated at the optimal Youden index. The accuracy of RM in evaluating fluid responsiveness in patients with lung-protective ventilation was evaluated. Results Compared with those before RM, both groups showed significant decreases in MAP and VTI after RM (P<0.05), and there were no statistical differences in heart rate before and after RM in the two groups (P>0.05). Compared with group N, △HR increased in group R (P<0.05), while △MAP and △VTI decreased in group R (P<0.05). According to ROC analysis, the cut-off value of △VTI in predicting positive fluid responsiveness in patients with lung protective ventilation was 18.065%, with a sensitivity of 92.3% and a specificity of 73.7%, and the area under the curve (AUC) was 0.893 [[95% confidence interval (CI) 0.800, 0.986], P<0.05]. The cut-off value of △MAP in predicting positive fluid responsiveness in patients with lung protective ventilation was 11.120%, with a sensitivity of 73.1% and a specificity of 84.2%, and the AUC was 0.864 [(95%CI 0.762, 0.967), P<0.05]. The cut-off value of △HR in predicting positive fluid responsiveness in lung protective ventilation patients was 1.575%, with a sensitivity of 69.2% and a specificity of 52.6%, and the AUC was 0.596 [(95%CI 0.427, 0.765), P>0.05]. Conclusions △VTI induced by lung recruitment maneuver can accurately predict fluid responsiveness in patients with lung protective ventilation. At the maximal Youden index, the cut-off of △VTI is 18.065%, with a sensitivity of 92.3% and a specificity of 73.7%.
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