经肝测量下腔静脉直径评估机械通气患者容量反应性研究

The application of transhepatic inferior vena cava view in assessment of the fluid responsiveness in mechanical ventilated patients

目的分析机械通气患者经肝和经剑突下测量下腔静脉直径的相关性,评价经肝测量下腔静脉直径在患者容量状态及容量反应性中的诊断价值。方法提取超声数据库中符合纳入标准的67例机械通气患者数据。二维超声模式测量经剑突下下腔静脉直径(IVCSP)和经肝下腔静脉直径(IVCTH)并分析两者的相关性;[(IVCmax-IVCmin)/IVCmin]计算IVCTH膨胀指数,以IVCSP为金标准检验其预测价值及诊断阈值。结果(1)超声测量呼气末IVCTH与IVCSP具有较好相关性(r=0.71,P<0.05);用于容量状态评估时,一致性较差(Kappa值0.5475)。(2)以IVCTH <1.39cm判为容量状态不足的优化敏感度为83.33%,特异度为22.95%;以IVCTH>2.1cm判为容量状态过负荷的敏感度为33.33%,优化特异度为83.61%。(3)以IVCTH膨胀指数评判容量反应性,当切点值>14%时,敏感度为71.87%,特异度为82.86%;切点值<5%时,优化敏感度为87.5%,特异度为34.29%;切点值>23%时,其敏感度为56.25%,优化特异度为88.57%。结论超声评估机械通气患者经肝与剑突下测量下腔静脉直径有较好相关性,其膨胀指数评估容量反应性也有较好的诊断价值,临床可选用不同截点值来分别优化敏感度与特异度。

Objective To evaluate the correlation between the Subxiphorid Inferior Vena Cava (IVC SP ) and Transhepatic Inferior Vena Cava (IVC TH ) and investigate the diagnostic value of IVC TH in assessment of the volume status and fluid responsiveness in mechanical ventilated patients. Methods A study was made in 67 mechanical ventilated patients who were extracted from the ultrasonic database between March 2015 and June 2015. All the patients were both measured the IVC SP and IVC TH through two-dimensional echocardiography. The correlation and consistency was analyzed between the data of two different position. In addition, the distensibility index of the IVC (dIVC) was calculated as the ratio of IVC SP [(IVCmax-IVCmin)/IVCmin] and expressed as a percentage to predict the consistency and cutoff value of the distensibility index of IVC TH . Results There was a correlation between the IVC SP and IVC TH (r=0.71, P <0.05) and poor consistency for volume status assessment (Kappa value: 0.5475). On volume status assessment, IVC TH <1.38cm indicated hypovolemia (optimized sensitivity was 83.33%, specificity was 22.95%). IVC TH >2.1cm indicated that the volume was overload (sensitivity was 33.33%, optimized specificity was 83.61%). On volume responsiveness assessment, when the cut-off value was 14%, the sensitivity was 71.87% and specificity was 82.86%. When the cut-off value was 5%, the optimized sensitivity was 87.50% and specificity was 34.29%. When the cut-off value was 23%, the sensitivity was 71.87% and optimized specificity was 82.86%. Conclusion There was a good correlation between IVC SP and IVC TH in mechanical ventilated patients. The distensibility index had a good diagnostic value for volume responsiveness assessment and different cut-off values can be used to optimize sensitivity and specificity.