Service de médecine intensive-réanimation, Hôpital de Bicêtre, Hôpitaux universitaires Paris-Saclay, Assistance publique-Hôpitaux de Paris, Le Kremlin-Bicêtre, France.
Inserm UMR S_999, Université Paris-Saclay, Le Kremlin-Bicêtre, France.
Crit Care Med. 2021 Feb 1;49(2):e151-e160. doi: 10.1097/CCM.0000000000004768.
The end-expiratory occlusion test for assessing preload responsiveness consists in interrupting mechanical ventilation for 15 seconds at end-expiration and measuring the cardiac index changes. The perfusion index is the ratio between the pulsatile and the nonpulsatile portions of the plethysmography signal and is, in part, determined by stroke volume. We tested whether the end-expiratory occlusion-induced changes in perfusion index could detect a positive passive leg raising test, suggesting preload responsiveness.
Observational study.
Medical ICU.
Thirty-one ventilated patients without atrial fibrillation.
We measured perfusion index (Radical-7 device; Masimo Corp., Irvine, CA) and cardiac index (PiCCO2; Pulsion Medical Systems, Feldkirchen, Germany) before and during a passive leg raising test and a 15-second end-expiratory occlusion.
In 19 patients with a positive passive leg raising test (increase in cardiac index ≥ 10%), compared to the baseline value and expressed as a relative change, passive leg raising increased cardiac index and perfusion index by 17% ± 7% and 49% ± 23%, respectively, In these patients, end-expiratory occlusion increased cardiac index and perfusion index by 6% ± 2% and 11% ± 8%, respectively. In the 12 patients with a negative passive leg raising test, perfusion index did not significantly change during passive leg raising and end-expiratory occlusion. Relative changes in perfusion index and cardiac index observed during all interventions were significantly correlated (r = 0.83). An end-expiratory occlusion-induced relative increase in perfusion index greater than or equal to 2.5% ([perfusion index during end-expiratory occlusion-perfusion index at baseline]/perfusion index at baseline × 100) detected a positive passive leg raising test with an area under the receiver operating characteristic curve of 0.95 ± 0.03. This threshold is larger than the least significant change observed for perfusion index (1.62% ± 0.80%).
Perfusion index could be used as a reliable surrogate of cardiac index for performing the end-expiratory occlusion test. Confirming previous results, the relative changes in perfusion index also reliably detected a positive passive leg raising test.
评估前负荷反应性的呼气末阻断试验包括在呼气末阻断机械通气 15 秒，并测量心指数的变化。灌注指数是容积描记信号的搏动和非搏动部分的比值，部分取决于每搏量。我们测试了呼气末阻断引起的灌注指数变化是否可以检测到阳性的被动抬腿试验，提示前负荷反应性。
观察性研究。
医疗 ICU。
31 例无房颤的通气患者。
我们在被动抬腿试验和 15 秒呼气末阻断前和期间测量了灌注指数（Radical-7 设备；Masimo 公司，尔湾，加利福尼亚州）和心指数（PiCCO2；Pulsion 医疗系统，费尔德基希海姆，德国）。
在 19 例被动抬腿试验阳性（心指数增加≥10%）的患者中，与基础值相比，以相对变化表示，被动抬腿使心指数和灌注指数分别增加 17%±7%和 49%±23%。在这些患者中，呼气末阻断使心指数和灌注指数分别增加 6%±2%和 11%±8%。在 12 例被动抬腿试验阴性的患者中，被动抬腿和呼气末阻断期间灌注指数没有显著变化。在所有干预措施中观察到的灌注指数和心指数的相对变化明显相关（r=0.83）。在 2.5%及以上的呼气末阻断引起的相对灌注指数增加（[呼气末阻断期间的灌注指数-基础灌注指数]/基础灌注指数×100）可以检测到阳性的被动抬腿试验，其受试者工作特征曲线下面积为 0.95±0.03。该阈值大于观察到的灌注指数最小有意义变化（1.62%±0.80%）。
灌注指数可作为进行呼气末阻断试验时心指数的可靠替代指标。与先前的结果一致，灌注指数的相对变化也可靠地检测到阳性的被动抬腿试验。
