Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, China.
Medicine (Baltimore). 2020 Dec 18;99(51):e23764. doi: 10.1097/MD.0000000000023764.
Passive leg raising (PLR) is a convenient and reliable test to predict fluid responsiveness. The ability of thoracic electrical bioimpedance cardiography (TEB) to monitor changes of cardiac output (CO) during PLR is unknown.In the present study, we measured CO in 61 patients with shock or dyspnea by TEB and transthoracic echocardiography (TTE) during PLR procedure. Positive PLR responsiveness was defined as the velocity-time integral (VTI) ≥10% after PLR. TTE measured VTI in the left ventricular output tract. The predictive value of TEB parameters in PLR responders was tested. Furthermore, the agreement of absolute CO values between TEB and TTE measurements was assessed.Among the 61 patients, there were 28 PLR-responders and 33 non-responders. Twenty-seven patients were diagnosed with shock and 34 patients with dyspnea, with 55.6% (15/27) and 54.6% (18/34) non-responders, respectively. A change in TEB measured CO (ΔCO) ≥9.8% predicted PLR responders with 75.0% sensitivity and 78.8% specificity, the area under the receiver operating characteristic curve (AUROC) was 0.79. The Δd2Z/dt2 (a secondary derivative of the impedance wave) showed the best predictive value with AUROC of 0.90, the optimal cut point was -7.1% with 85.7% sensitivity and 87.9% specificity. Bias between TEB and TTE measured CO was 0.12 L/min, and the percentage error was 65.8%.TEB parameters had promising performance in predicting PLR responders, and the Δd2Z/dt2 had the best predictive value. The CO values measured by TEB were not interchangeable with TTE in critically ill settings.
被动抬腿（PLR）是一种预测液体反应性的方便可靠的方法。目前尚不清楚经胸电阻抗心排量（TEB）监测 PLR 期间心输出量（CO）变化的能力。在本研究中，我们通过 TEB 和经胸超声心动图（TTE）在 PLR 过程中测量了 61 例休克或呼吸困难患者的 CO。将 PLR 反应阳性定义为 PLR 后速度时间积分（VTI）≥10%。TTE 在左心室输出道测量 VTI。测试了 TEB 参数在 PLR 反应者中的预测价值。此外，还评估了 TEB 和 TTE 测量的绝对 CO 值之间的一致性。在 61 例患者中，有 28 例 PLR 反应者和 33 例非反应者。27 例诊断为休克，34 例诊断为呼吸困难，其中非反应者分别为 55.6%（15/27）和 54.6%（18/34）。TEB 测量的 CO（ΔCO）变化≥9.8%可预测 PLR 反应者，灵敏度为 75.0%，特异性为 78.8%，ROC 曲线下面积（AUROC）为 0.79。阻抗波的二次导数Δd2Z/dt2具有最佳的预测价值，AUROC 为 0.90，最佳截断点为-7.1%，灵敏度为 85.7%，特异性为 87.9%。TEB 和 TTE 测量的 CO 之间的偏差为 0.12L/min，百分比误差为 65.8%。TEB 参数在预测 PLR 反应者方面具有良好的性能，Δd2Z/dt2具有最佳的预测价值。在危重病环境中，TEB 测量的 CO 值与 TTE 不可互换。
