Diagnostic Accuracy of Transthoracic Echocardiography to Predict Fluid Responsiveness by Passive Leg Raising in the Critically Ill: A Meta-Analysis

Abstract

Background: Hemodynamic instability is common in critical patients and not all patients respond to fluid challenge, so we need accurate and rapid hemodynamic techniques to help the clinicians to guide fluid treatment. Numerous hemodynamic techniques have been used to predict fluid responsiveness till now. Transthoracic echocardiography (TTE) appears to have the ability to predict fluid responsiveness, but there is no consensus on whether it can be used by passive leg raising (PLR). Methods: We performed a literature search using MEDLINE (source PubMed, from 1947), EMBASE (from 1974) and the Cochrane Database of Systematic Reviews for prospective studies with no restrictions. Pooled effect estimates were obtained by using random-effects meta-analysis. Results: 7 prospective studies involving 261 patients and 285 boluses were identified. The pooled sensitivity and specificity of TTE are 86% (79% - 91%) and 90% (83% - 94%), respectively. The summary receiver operating characteristic (sROC) curve shows an optimum joint sensitivity and specificity of 0.88, with area under the sROC curve (AUC) of 0.94. The result of diagnostic odds ratio (DOR) is 50.62 (95% confidence interval [CI]: 23.70 - 108.12). The results of positive likelihood ratio (+LR) and negative likelihood ratio (?LR) are 7.07 (95% CI: 4.39 - 11.38) and 0.19 (95% CI: 0.13 - 0.28), which indicated strong diagnostic evidence. Conclusions: TTE is a repeatable and reliable noninvasive tool to predict fluid responsiveness in the critically ill during PLR with good test performance. This meta-analysis brings evidence to employ well-trained clinician-echocardiographers to assess patients’ volume statue via TTE to benefit daily work in intensive care units (ICUs).