Suction or non-suction to the underwater seal drains following pulmonary operation: meta-analysis of randomised controlled trials.

OBJECTIVES The decision to proceed to simple underwater seal drainage or to apply active suction to the underwater seal following pulmonary operation is a controversial one. For the sake of selecting the alternative to reduce postoperative air leakage, we performed a meta-analysis of randomised controlled trials (RCTs) to determine the benefit of suction or non-suction following lung surgery on patient outcomes. METHODS RCTs published in English from 1999 to 2009 were included. A fixed-effect model was developed for postoperative pneumothorax cases. A random-effects model was developed for quantitative data synthesis, including prolonged air-leak cases, duration of air leakage, time for the removal of chest tubes and hospital stay. RESULTS Odds ratio (95% confidence interval (CI)), expressed as suction versus non-suction, was 0.11 (0.03-0.49) for postoperative pneumothorax cases; relative risk was 1.48 (0.82-2.70) for prolonged air-leakage cases; weighted mean difference was 1.16 (-0.63 to 2.94) for the duration of air leakage, 0.96 (-0.12 to 2.05) for the time for removal of chest tubes and 2.19 (0.61-4.98) for the hospital stay. CONCLUSION There is no necessity to use suction in most cases, since it cannot decrease the incidence of prolonged air leak. However, suction can reduce the occurrence of postoperative pneumothorax resulting from early air leak. As a result, the early use of postoperative suction might be crucial to specific patients to whom early elimination of residual space is very important.