中心静脉血氧饱和度预测心脏术后患者容量反应性的价值

Central venous oxygen saturation changes in predicting volume responsiveness of mechanically ventilated patients after cardiac surgery

目的研究中心静脉血氧饱和度变化（△ScvO2）预测心脏术后机械通气患者容量反应性的价值。方法对心脏术后患者29例进行容量负荷试验。通过FIoTrac／Vigileo系统监测心排量（CO）、外周血管阻力指数（SVRI）、每博量变异（SVV）等血流动力学指标。通过中心静脉导管抽血测量中心静脉血氧饱和度（ScvO2）。根据容量负荷前后心排量增加值（△CO）是否〉12％分为有反应组和无反应组。通过直线相关回归分析△ScvO2与△CO关系。绘制ROC曲线评价△ScvO2、中心静脉压变化（ACVP）、动脉压变化（△MAP）、容量负荷前SVV预测容量反应性的价值。结果容量负荷后△ScvO2与△CO存在直线相关（r=0．670。P=0．000）。容量负荷后△ScvO2、△CVP、△MAP预测容量反应性曲线下面积分别是0．900（95％C10．777～1，P=0000）、0．450（95％CI0．235～0．665，P-0．647）、0．657（95％C10．455～0．859，P=O．150）；SVV曲线下面积0．833（95％CI0．684—0．982，P=0．002）。以△ScvO2取4％作为切点来预测容量反应性，其敏感度929％，特异度8617％。结论AScvO2可以作为预测心脏术后患者容量反应性的可靠指标，而且明显优于CVP、MAP等传统指标。

Objective To assess changes of central venous oxygen saturation （ △ScvO2）in predicting volume respon-siveness of mechanically ventilated patients after cardiac surgery. Methods A total of 29 mechanically ventilated patients after cardiac surgery were admitted from June 2010 to May 2011. Patients were treated with volume expansion （VE）. Cardiac output （CO）, systemic vascular resistance index （SVRI） and stroke volume variation （SVV） were measured with Vigileo/FIoTrac system. ScvO2 was measured before and after volume load through central venous catheter. Responders （R） were defined as patients who increased their CO （△CO）≥12% after VE, and nonresponders （NR） as patients with △CO〈12% after VE. ScvO2 and CO changes after VE were analyzed using linear correlation and regression. The role of △ScvO2, central venous pressure changes （△CVP）, mean arterial pressure change （△MAP） and SVV before VE were evaluated by receiver operating characteristic（ROC） curves. Results AScvO2 was significantly correlated with△CO after VE （r=0.670, P =0.000）. The areas under ROC curves （AUC） were 0.900（95%CI：0.777 - 1, P =0.000 ）, 0.450（ 95%CI：0.235 - 0.665, P =0.647 ）, 0.657（ 95%CI：0.455 - 0.859, P =0.150 ） and 0.833 （95%CI：0.684 -0.982, P =0.002）for △ScvO2,△CVP, △MAP and SVV,respectively. △ScvO2 threshold value of 4% allowed the definition of R and NR patients with 92.9% sensitivity and 86.7% specificity. Conclusion △ScvO2 can serve as valid indicator of predicting volume responsiveness in mechanically ventilated patients after cardiac surgery,and it is more realibale than conventional indicators such as CVP or MAP.