Rauch Simon, Seraglio Paolo Mario, Cappello Tomas Dal, Roveri Giulia, Falk Markus, Bock Matthias
Department of Anesthesia and Intensive Care Medicine, "F. Tappeiner" Hospital Merano, 39012, Merano, Italy.
Eurac Research, Institute of Mountain Emergency Medicine, 39100, Bolzano, Italy.
J Clin Monit Comput. 2025 Apr 7. doi: 10.1007/s10877-025-01292-0.
Predicting fluid responsiveness is crucial in treating circulatory failure, as only about half of patients benefit from volume expansion by increasing cardiac output (CO). Dynamic tests like passive leg raising (PLR) are preferred over static parameters. While PLR reliably predicts fluid responsiveness, it typically requires invasive measurement of stroke volume (SV) or CO. The perfusion index (PI) and pleth variability index (PVI) are non-invasive metrics derived from oxygen saturation signals. PI has been shown to correlate with SV, and PVI has predicted fluid responsiveness in mechanically ventilated patients, but their role in spontaneously breathing patients remains unclear. This study aimed to assess whether PI and PVI could predict fluid responsiveness in post-surgical, spontaneously breathing patients during a PLR test. The hypothesis was that PI would increase and PVI would decrease in fluid responders. The prospective study included spontaneously breathing patients after major abdominal surgery in the ICU of Merano Hospital, Italy. SV and CO were measured using the FloTrac™ system, and PI and PVI were assessed using the Radical 7 monitor. Patients were considered responders if SV increased by ≥ 10% during the PLR test. Of the 47 patients enrolled, 23 (48.9%) were fluid responders. The percentage change in PI from baseline to 60 s into the PLR test was + 41.2% in responders and + 11.3% in non-responders. A PI increase of ≥ 23% predicted responders with 70% sensitivity and 75% specificity, with an area under the ROC curve of 0.74. Twenty-two patients (47%) were inside the grey zone. PVI did not differ significantly between groups. In conclusion, PI could be a helpful non-invasive tool for predicting fluid responsiveness during a PLR test in spontaneously breathing patients, though its diagnostic accuracy appears to be moderate.
预测液体反应性对于治疗循环衰竭至关重要，因为只有约一半的患者通过增加心输出量（CO）从容量扩充中获益。像被动抬腿试验（PLR）这样的动态测试优于静态参数。虽然PLR能可靠地预测液体反应性，但通常需要有创测量每搏输出量（SV）或CO。灌注指数（PI）和脉搏波变异指数（PVI）是从血氧饱和度信号得出的无创指标。PI已被证明与SV相关，且PVI已在机械通气患者中预测了液体反应性，但其在自主呼吸患者中的作用仍不明确。本研究旨在评估PI和PVI能否在PLR测试期间预测术后自主呼吸患者的液体反应性。假设是液体反应者的PI会升高而PVI会降低。这项前瞻性研究纳入了意大利梅拉诺医院重症监护病房接受大型腹部手术后的自主呼吸患者。使用FloTrac™系统测量SV和CO，并使用Radical 7监护仪评估PI和PVI。如果在PLR测试期间SV增加≥10%，则患者被视为反应者。在纳入的47例患者中，23例（48.9%）是液体反应者。从基线到PLR测试60秒时PI的百分比变化在反应者中为+41.2%，在无反应者中为+11.3%。PI升高≥23%预测反应者的敏感性为70%，特异性为75%，ROC曲线下面积为0.74。22例患者（47%）处于灰色区域。两组之间PVI无显著差异。总之，PI可能是预测自主呼吸患者PLR测试期间液体反应性的一种有用的无创工具，尽管其诊断准确性似乎为中等。
