Hospices Civils de Lyon, Department of Anesthesiology and Intensive Care, Louis Pradel Hospital, Claude Bernard Lyon 1 University, INSERM ERI 22, Lyon, France.
Anesth Analg. 2010 Mar 1;110(3):792-8. doi: 10.1213/ANE.0b013e3181cd6d06.
Pleth variability index (PVI) is a new algorithm allowing automated and continuous monitoring of respiratory variations in the pulse oximetry plethysmographic waveform amplitude. PVI can predict fluid responsiveness noninvasively in mechanically ventilated patients during general anesthesia. We hypothesized that PVI could predict the hemodynamic effects of 10 cm H2O positive end-expiratory pressure (PEEP).
We studied 21 mechanically ventilated and sedated patients in the postoperative period after coronary artery bypass grafting. Patients were monitored with a pulmonary artery catheter and a pulse oximeter sensor attached to the index finger. Hemodynamic data (cardiac index [CI], PVI, pulse pressure variation, central venous pressure) were recorded at 3 successive tidal volumes (V(T)) (6, 8, and 10 mL/kg body weight) during zero end-expiratory pressure (ZEEP) and then after addition of a 10 cm H2O PEEP for each V(t). Hemodynamically unstable patients were defined as those with a >15% decrease in CI after the addition of PEEP.
PEEP induced changes in CI and PVI for V(t) of 8 and 10 mL/kg. Hemodynamic instability occurred in 5 patients for a V(T) of 6 mL/kg, in 6 patients for a V(T) of 8 mL/kg, and in 9 patients for a V(T) of 10 mL/kg. For V(T) of 8 mL/kg, a PVI threshold value of 12% during ZEEP predicted hemodynamic instability with a sensitivity of 83% and a specificity of 80% (area under the receiver operating characteristic curve 0.806; P = 0.03). For V(T) of 10 mL/kg, a PVI threshold value of 13% during ZEEP predicted hemodynamic instability with a sensitivity of 78% and a specificity of 83% (area under the receiver operating characteristic curve 0.829; P = 0.01).
PVI may be useful in automatically and noninvasively detecting the hemodynamic effects of PEEP when V(T) is >8 mL/kg in ventilated and sedated patients with acceptable sensitivity and specificity.
容积脉搏变异指数（PVI）是一种新的算法，可对脉搏血氧容积描记波幅度的呼吸变化进行自动和连续监测。在全身麻醉下机械通气的患者中，PVI 可无创预测液体反应性。我们假设 PVI 可预测 10cmH2O 呼气末正压（PEEP）的血流动力学效应。
我们研究了 21 例冠状动脉旁路移植术后机械通气和镇静的患者。患者使用肺动脉导管和连接至食指的脉搏血氧仪传感器进行监测。在零呼气末正压（ZEEP）下，记录 3 个连续潮气量（V(T)）（6、8 和 10mL/kg 体重）时的血流动力学数据（心指数[CI]、PVI、脉搏压变异、中心静脉压），然后在每个 V(t) 时增加 10cmH2O PEEP。血流动力学不稳定的患者定义为在添加 PEEP 后 CI 降低>15%的患者。
PEEP 引起 CI 和 PVI 随 V(t)为 8 和 10mL/kg 的变化。V(T)为 6mL/kg 时，5 例患者出现血流动力学不稳定，V(T)为 8mL/kg 时，6 例患者出现血流动力学不稳定，V(T)为 10mL/kg 时，9 例患者出现血流动力学不稳定。对于 V(T)为 8mL/kg，ZEEP 时 PVI 阈值为 12%，预测血流动力学不稳定的灵敏度为 83%，特异性为 80%（接受者操作特征曲线下面积 0.806；P=0.03）。对于 V(T)为 10mL/kg，ZEEP 时 PVI 阈值为 13%，预测血流动力学不稳定的灵敏度为 78%，特异性为 83%（接受者操作特征曲线下面积 0.829；P=0.01）。
对于 V(T)大于 8mL/kg 的机械通气和镇静患者，PVI 可能有助于自动和无创地检测 PEEP 的血流动力学效应，具有可接受的灵敏度和特异性。
