The impact of suction addition to simple water seal on the outcomes after pulmonary surgery: A meta-analysis

Background. Chest tube drainage during pulmonary surgery is fundamental to removing air and fluid, as well as for lung re-expansion. However, the advantages of adding external suction to the water seal are under debate. Objectives. The aim of the study was to conduct a meta-analysis in order to assess the effects of adding suction to a simple water seal on the outcomes of lung surgery. Materials and methods. A search of the literature up to November 2021 found 14 studies with 2449 lung surgery patients. Of these patients, 1092 received suction drainage and 1357 received a simple water-seal drainage. The studies reported the effects of adding suction to a simple water seal on postoperative outcomes after lung surgery. A random-or fixed-effect model determined the odds ratio (OR) or mean difference (MD) with 95% confidence intervals (95% CIs) to compare the outcomes. Results. In patients undergoing lung surgery, suction resulted in a substantially longer chest tube duration (MD = 0.74, 95% CI: 0.90-1.40, p = 0.03, Z = 2.21) and a smaller postoperative pneumothorax (OR = 0.27, 95% CI: 0.13-0.59, p = 0.02, Z = 2.24) than a simple water seal. However, no differences existed in prolonged air leak (p = 0.91, Z = 0.12), air leak duration (p = 0.28, Z = 1.07) or length of hospital stay (p = 0.23, Z = 1.2) between the 2 approaches. Conclusions. Suction led to considerably longer chest tube duration and lower postoperative pneumothorax, but no significant difference in sustained air leak, air leak duration or length of hospital stay was observed compared to a simple water seal in patients undergoing pulmonary surgery. Further research is needed to validate these findings and increase confidence, particularly regarding the postoperative pneumothorax results.