Utility of pleural effusion drainage in the ICU: An updated systematic review and META-analysis

The effects on the respiratory or hemodynamic function of drainage of pleural effusion on critically ill patients are not completely understood. First outcome was to evaluate the PiOevaluation of A-a gradient, End-Expiratory lung volume (EELV), heart rate (HR), mean arterial pressure (mAP), left ventricular end-diastolic volume (LVEDV), stroke volume (SV), cardiac output (CO), ejection fraction (EF), and E/A waves ratio (E/A). A tertiary outcome: evaluation of pneumothorax and hemothorax complications.Searches were performed on MEDLINE, EMBASE, COCHRANE LIBRARY, SCOPUS and WEB OF SCIENCE databases from inception to June 2018 (PROSPERO CRD42018105794).We included 31 studies (2265 patients). Pleural drainage improved the P/F ratio (SMD: -0.668; CI: -0.947-0.389; p .001), EELV (SMD: -0.615; CI: -1.102-0.219; p = .013), but not A-a gradient (SMD: 0.218; CI: -0.273-0.710; p = .384). HR, mAP, LVEDV, SV, CO, E/A and EF were not affected. The risks of pneumothorax (proportion: 0.008; CI: 0.002-0.014; p = .138) and hemothorax (proportion: 0.006; CI: 0.001-0.011; p = .962) were negligible.Pleural effusion drainage improves oxygenation of critically ill patients. It is a safe procedure. Further studies are needed to assess the hemodynamic effects of pleural drainage.