摘要目的:分析下腔静脉呼吸变异度（inferior vena cava respiratory variation index, IVC-RVI）预测膝关节镜手术驱血引起的容量变化，为临床预测驱血所引起容量变化提供帮助。方法:选取2018年10月至2019年7月间全身麻醉下膝关节镜手术患者85例为研究对象，所有患者均使用驱血带进行驱血。记录所有患者驱血前IVC-RVI和驱血前后的心率、MAP、每搏输出量（stroke volume, SV）。以每搏变异度（stroke volume variability, SVV）≥15%作为评价有容量反应性的金标准，将所有患者分为有容量反应性（CR）组和无容量反应性（NCR）组。分析IVC-RVI与SVV相关性，绘制IVC-RVI预测CR的受试者工作特征（receiver operating characteristic，ROC）曲线，计算曲线下面积（area under the curve，AUC）、Youden指数、敏感度和特异性。结果:患者IVC-RVI与SVV呈线性正相关关系（ r=0.655， P<0.05）。IVC-RVI预测CR的AUC为0.899（95%CI=0.835~0.963, P<0.05）。IVC-RVI预测切点为17.3%，预测敏感度79.2%，特异性86.5%。 结论:全身麻醉下膝关节镜手术中，IVC-RVI可有效预测驱血所引起容量变化，具有一定的临床应用价值。

abstractsObjective:To evaluate the use of inferior vena cava respiratory variation index (IVC-RVI) in predicting the volume changes caused by tourniquet placement during knee arthroscopic surgery, so as to facilitate clinical prediction of volume changes caused by tourniquet placement.Methods:A total of 85 patients undergoing knee arthroscopic surgery under general anesthesia from October 2018 to July 2019 were enrolled. Tourniquets were used for all the patients. Their IVC-RVI before tourniquet placement as well as heart rate, mean arterial pressure (MAP) and stroke volume (SV) before and after tourniquet placement were recorded. The gold standard for evaluating the capacity reactivity was stroke volume variability (SVV)≥15%, and all the patients were divided into a capacity reactivity (CR) group and a non-capacity reactivity (NCR) group. The correlation between IVC-RVI and SVV was analyzed. The receiver operating characteristic (ROC) curve of IVC-RVI in predicting CR was plotted to calculate the area under the curve (AUC), Youden index and sensitivity and specificity.Results:There was a positive linear correlation between IVC-RVI and SVV ( r=0.655, P<0.05). The AUC of IVC-RVI in predicting CR was 0.899 (95%CI=0.835-0.963, P<0.05). The cut-off value was 17.3%, with a sensitivity of 79.2% and a specificity of 86.5%. Conclusions:During knee arthroscopic surgery under general anesthesia, IVC-RVI can effectively predict the volume changes caused by tourniquet placement, with certain clinical application value.