Abstract
OBJECTIVE: To assess whether skin blood flow (SBF) monitoring combined with passive leg raising (PLR) can predict microvascular fluid responsiveness in septic patients. DESIGN: Prospective observational study. SETTING: Single-center, 18-bed medical ICU in a tertiary university hospital in Paris, France. PATIENTS: Adult patients with sepsis requiring intravenous fluid administration. INTERVENTIONS: Patients underwent a standardized PLR maneuver followed by a 500 mL saline fluid administration. Peripheral SBF was continuously monitored by fingertip laser Doppler flowmetry. MEASUREMENTS AND MAIN RESULTS: Of 37 patients included, 27 (73%) were classified as fluid responders, defined by a > 15% increase in SBF after volume expansion (ΔSBF-VE). In responders, SBF increased significantly during PLR (ΔSBF-PLR 40% [21-105]), while no significant changes were observed in non-responders. SBF variations induced by PLR (ΔSBF-PLR) strongly predicted fluid responsiveness with an AUROC of 0.95 [0.86-1.00] (P < 0.001). A ΔSBF-PLR threshold of > 6% identified responders with an 96 [80-100] % sensitivity and 90 [59-100] % specificity. Positive predictive value was 96 [80-100] % and negative predictive value was 91 [59-100]. Changes in SBF did not correlate with changes in cardiac output after volume expansion (R² =0.04, P = 0.28). CONCLUSIONS: In septic patients, PLR-induced changes in SBF reliably predict peripheral microvascular responsiveness to a subsequent volume expansion. This simple, non-invasive approach may facilitate personalized fluid strategies aimed at optimizing microvascular tissue perfusion.