Abstract / Summary
Passive leg raising test (PLR) is a well-known method for predicting fluid responsiveness. Although the internationally recommended PLR procedure requires a mechanical bed to change the patient’s position, manual leg lifting is often applied in clinical practice, particularly in resource-limited settings. The accuracy of this manual PLR remains unknown. Patients with shock who required assessment of fluid responsiveness were prospectively included. Mechanical-bed and manual PLR were performed sequentially. Subsequently, the prespecified reference standard of positive fluid responsiveness was defined as an increase in cardiac output (CO) of more than 10% after a fluid challenge test. Sixty-six measurements were obtained from 32 patients. The positive rate of fluid responsiveness was 51.5%. The area under the receiver operating characteristic curve (AUC) was 0.840 for mechanical-bed PLR and 0.745 for manual PLR, the between-method difference was 0.095 (95% CI, -0.004 to 0.202; P = 0.061). Specificity of mechanical-bed PLR was significantly higher than that of manual PLR (71.9% vs. 53.1%, P = 0.002). The exploratory Youden-index threshold was a ΔCO of 10.53% for mechanical-bed PLR and a ΔCO of 12.74% for manual PLR. In this cohort, mechanical-bed PLR demonstrated higher specificity than manual PLR for assessing fluid responsiveness, whereas superior overall discriminative ability was not demonstrated. Future larger, multicenter studies should investigate the mechanisms underlying this difference and determine the optimal diagnostic threshold for manual PLR.