Table_1_Prediction of Fluid Responsiveness by the Effect of the Lung Recruitment Maneuver on the Perfusion Index in Mechanically Ventilated Patients During Surgery.DOCX

IntroductionExcessive or inadequate fluid administration during perioperative period affects outcomes. Adjustment of volume expansion (VE) by performing fluid responsiveness (FR) test plays an important role in optimizing fluid infusion. Since changes in stroke volume (SV) during lung recruitment maneuver (LRM) can predict FR, and peripheral perfusion index (PI) is related to SV; therefore, we hypothesized that the changes in PI during LRM (ΔPILRM) could predict FR during perioperative period.
MethodsPatients who were scheduled for elective non-laparoscopic surgery under general anesthesia with a mechanical ventilator and who required VE (250 mL of crystalloid solution infusion over 10 min) were included. Before VE, LRM was performed by a continuous positive airway pressure of 30 cm H2O for 30 sec; hemodynamic variables with their changes (PI, obtained by pulse oximetry; and ΔPILRM, calculated by using [(PI before LRM—PI after LRM)/PI before LRM]*100) were obtained before and after LRM. After SV (measured by esophageal doppler) and PI had returned to the baseline values, VE was infused, and the values of these variables were recorded again, before and after VE. Fluid responders (Fluid-Res) were defined by an increase in SV ≥10% after VE. Receiver operating characteristic curves of the baseline values and ΔPILRM were constructed and reported as areas under the curve (AUC) with 95% confidence intervals, to predict FR.
ResultsOf 32 mechanically ventilated adult patients included, 13 (41%) were in the Fluid-Res group. Before VE and LRM, there were no differences in the mean arterial pressure (MAP), heart rate, SV, and PI between patients in the Fluid-Res and fluid non-responders (Fluid-NonRes) groups. After LRM, SV, MAP, and, PI decreased in both groups, ΔPILRM was greater in the Fluid-Res group than in Fluid-NonRes group (55.2 ± 17.8% vs. 35.3 ± 17.3%, p < 0.001, respectively). After VE, only SV and cardiac index increased in the Fluid-Res group. ΔPILRM had the highest AUC [0.81 (0.66–0.97)] to predict FR with a cut-off value of 40% (sensitivity 92.3%, specificity 73.7%).
ConclusionsΔPILRM can be applied to predict FR in mechanical ventilated patients during the perioperative period.

引言
围手术期（perioperative period）补液过量或不足均会影响患者预后。通过液体反应性（fluid responsiveness, FR）试验调整容量扩张（volume expansion, VE）策略，对优化临床输液管理具有重要意义。鉴于肺复张手法（lung recruitment maneuver, LRM）期间的每搏输出量（stroke volume, SV）变化可预测液体反应性，且外周灌注指数（peripheral perfusion index, PI）与每搏输出量密切相关，本研究假设肺复张期间的PI变化（ΔPILRM）可用于预测围手术期患者的液体反应性。

方法
本研究纳入择期行非腹腔镜全身麻醉机械通气手术、且需实施容量扩张（VE：10 min内输注250 mL晶体液）的成人患者。在VE实施前，采用30 cm H₂O持续气道正压通气30 s完成肺复张手法（LRM）；分别于LRM前后记录血流动力学指标及其变化值，其中外周灌注指数（PI）通过脉搏血氧饱和度仪获取，ΔPILRM计算公式为[(LRM前PI - LRM后PI)/LRM前PI]×100。待经食管多普勒测量的每搏输出量（SV）及PI恢复至基线水平后，输注VE溶液，并再次记录VE前后的上述指标。液体反应阳性者（Fluid-Res）定义为VE实施后SV增幅≥10%。绘制基线值及ΔPILRM的受试者工作特征（receiver operating characteristic, ROC）曲线，以曲线下面积（area under the curve, AUC）及其95%置信区间报告其预测液体反应性的效能。

结果
共纳入32例成人机械通气患者，其中13例（41%）归入液体反应阳性组（Fluid-Res）。在VE及LRM实施前，液体反应阳性组与液体反应阴性组（Fluid-NonRes）患者的平均动脉压（mean arterial pressure, MAP）、心率、每搏输出量及PI均无显著组间差异。LRM后，两组患者的SV、MAP及PI均出现下降，且液体反应阳性组的ΔPILRM显著高于液体反应阴性组（55.2±17.8% vs. 35.3±17.3%，p<0.001）。VE实施后，液体反应阳性组仅SV及心脏指数出现升高。ΔPILRM预测液体反应性的曲线下面积最高，达0.81（95%置信区间：0.66~0.97），最佳截断值为40%（灵敏度92.3%，特异度73.7%）。

结论
ΔPILRM可用于预测机械通气围手术期患者的液体反应性。