摘要目的 评价被动抬腿试验联合无创心排血量监测系统(USCOM)预测自主呼吸患者的容量反应性.方法 采用前瞻性、观察性队列研究设计方法,选择33例有自主呼吸且需补液的患者,先后进行被动抬腿试验和容量负荷试验,在每个试验前后分别采用经胸超声心动图(TTE)和USCOM测量每搏量(SV).根据对容量负荷试验的反应(以容量负荷试验后SVTTE增加≥15%者为有反应)将患者分为有反应组和无反应组.观察试验后SV的变化(△SV)及其相关性.结果 33例患者共行容量负荷试验36例次,有反应组24例次,无反应组12例次.两组一般资料及初始床头抬高45°时的血流动力学指标无明显差异.被动抬腿试验后,有反应组SVTTE和SVUSCOM的增加量均明显大于无反应组[△SVTTE:(21.7±13.2)%比(4.8±9.4)%,△SVUSCOM:(23.5±13.0)%比(4.6±8.9)%,均P＜0.01];△SVTTE与△SVUSCOM呈显著正相关(r=0.792,P＜0.01).容量负荷试验后,有反应组SVTTE和SVUSCOM的增加量均明显大于无反应组[△SVTTE:(27.3±14.1)%比(7.2±8.4)%,△SVUSCOM:(25.4±13.8)%比(6.7±8.6)%,均P＜0.01];△SVTTE与△SVUSCOM呈显著正相关(r=0.855,P＜0.01).用△SVTTE≥15%预测容量反应性,其敏感性为100.0%[95%可信区间(95%CI)85.0～100.0],特异性为83.3%(95%CI 68.4～98.2);而用△SVUSCOM≥15%预测容量反应性,其敏感性为83.3%(95%CI 66.1～100.0),特异性为94.4%(95%CI 83.9～100.0).被动抬腿试验后△SVTTE与△SVUSCOM的受试者工作特征曲线下面积比较差异无统计学意义(0.95±0.04比0.93±0.05,P＞0.05).结论 用USCOM测量被动抬腿试验后的△SV可反映自主呼吸患者液体治疗时的容量反应性,用以指导患者的液体治疗.

abstractsObjective To investigate whether passive leg raising(PLR)combined with ultrasonic cardiac output monitoring system(USCOM)could be used to predict the hemodynamic response to volume expansion(VE)in patients with spontaneous respiration. Methods The study was performed with prospective, cohort study method. Thirty-three patients with spontaneous breathing activity who were admitted to the intensive care unit(ICU)from October 2009 to April 2010 were included. Measurements of stroke volume(SV)were obtained with transthoracic echocardiography(TTE)and USCOM. Patients were considered to be responders to VE if SVTTE increased≥ 15%. Based on the responsiveness of VE, all the patients were divided into responders and non-responders. The change in SV(△SV)after the experiment and its correlation were observed. Results A total of 36 fluid load tests in 33 patients were evaluated resulting in 24 responders and 12 non-responders. There was no significant difference between two groups in the clinical data and hemodynamics parameters at incipient stage when head side of bed was raised for 45°. After PLR,the △SVTTE and △SVUSCOM in responder group were significantly higher than those in non-responder group [△SVTTE:(21.7±13.2)% vs.(4.8±9.4)%, △SVUSCOM:(23.5±13.0)% vs.(4.6±8.9)%, both P＜0. 01], with positive correlation between △SVTTE and △SVUSCOM(r = 0. 792, P＜0. 01). After VE, the △SVTTE and △SVUSCOM in responder group were significantly higher than those in non-responder group [△SVTTE:(27.3±14.1)% vs.(7.2±8.4)%, △SVUSCOM:(25.4±13.8)% vs.(6.7±8.6)%, both P＜0. 01], with positive correlation between △SVTTE and △SVUSCOM(r= 0. 855, P＜0. 01). The △SVTTE≥ 15%during PLR was predictive of response to VE with a sensitivity of 100. 0%[95% confidence interval (95%CI)85.0 - 100. 0]and a specificity of 83. 3%(95%CI 68.4 - 98. 2). The △SVUSCOM≥15% during PLR was predictive of response to VE with a sensitivity of 83.3%(95%CI 66. 1 - 100. 0)and a specificity of 94.4%(95%CI 83. 9 - 100. 0). There was no difference between the area under the receiver operating characteristic(ROC)curve for PLR-induced △SVTTE and △SVUSCOM(0. 95±0. 04 vs. 0. 93±0. 05, P＞0. 05).Conclusion PLR combined with USCOM can predict the hemodynamic response to VE in spontaneously breathing patients, and the procedure can be used to guide fluid therapy in spontaneously breathing patients.