Predicting fluid responsiveness with transthoracic echocardiography is not yet evidence based

An essential part of intensive care is to accurately identify fluid responders among patients with circulatory failure. Over the past few years, new techniques have been assessed for rapid and non-invasive prediction of fluid responsiveness. As transthoracic echocardiography (TTE) is becoming an integrated tool in the intensive care unit, this systematic review examined studies evaluating the predictive value of TTE for fluid responsiveness. In October 2012, we searched Pubmed, EMBASE and Web of Science for studies evaluating the predictive value of TTE-derived variables for fluid responsiveness defined as change in thermodilution cardiac output or stroke volume after a fluid challenge or a passive leg raising test. The use of thermodilution was used as inclusion criterion because it is the only method validated to show the change in cardiac output or stroke volume, which defines fluid responsiveness. Of the 4294 evaluated citations, only one study fully met our inclusion criteria. In this study, the predictive value of variations in inferior vena cava diameter (> 16%) for fluid responsiveness was moderate with sensitivity of 71% [95% confidence interval (CI) 44-90], specificity of 100% (95% CI 73-100) and an area under the receiver operating curve of 0.90 (95% CI 0.73-0.98). Only one study of TTE-based methods fulfilled the criteria for valid assessment of fluid responsiveness. Before recommending the use of TTE in predicting fluid responsiveness, proper evaluation including thermodilution technique as the gold standard is needed.