Diagnostic accuracy of passive leg raising for prediction of fluid responsiveness in adults: systematic review and meta-analysis of clinical studies

To systematically review the published evidence on the ability of passive leg raising-induced changes in cardiac output (PLR-cCO) and in arterial pulse pressure (PLR-cPP) to predict fluid responsiveness. MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews were screened. Clinical trials on human adults published as full-text articles in indexed journals were included. Two authors independently used a standardized form to extract data about study characteristics and results. Study quality was assessed by using the QUADAS scale. Nine articles including a total of 353 patients were included in the final analysis. Data are reported as point estimate (95% confidence intervals). The pooled sensitivity and specificity of PLR-cCO were 89.4% (84.1-93.4%) and 91.4% (85.9-95.2%) respectively. Diagnostic odds ratio was 89.0 (40.2-197.3). The pooled area under the receiver operating characteristics curve (AUC) was 0.95 (0.92-0.97). The pooled correlation coefficient r between baseline value of PLR-cCO and CO increase after fluid load was 0.81 (0.75-0.86). The pooled difference in mean PLR-cCO values between responders and non-responders was 17.7% (13.6-21.8%). No significant differences were identified between patients adapted to ventilator versus those with inspiratory efforts nor between patients in sinus rhythm versus those with arrhythmias. The pooled AUC for PLR-cPP was 0.76 (0.67-0.86) and was significantly lower than the AUC for PLR-cCO (p < 0.001). The pooled difference in mean PLR-cPP values between responders and non-responders was 10.3% (6.5-14.1%). Passive leg raising-induced changes in cardiac output can reliably predict fluid responsiveness regardless of ventilation mode and cardiac rhythm. PLR-cCO has a significantly higher predictive value than PLR-cPP.