ObjectiveTo systematically review the efficacy of closed and open tracheal suction system on the prevention of ventilator-associated pneumonia.MethodsThe Cochrane Library, CNKI, WanFang Data, Airiti Library, PubMed, CINAHL and Proquest databases were electronically searched to collect randomized controlled trials (RCTs) on closed and open tracheal suction system on the prevention of ventilator-associated pneumonia. Two reviewers independently screened literature, extracted data, and assessed the risk bias of included studies. Then, meta-analysis was performed by RevMan 5.3 software.ResultsA total of 11 RCTs involving 1 187 patients were included. The results of meta-analysis showed that compared with open tracheal suction system, closed tracheal suction system was associated with a reduced incidence of ventilator-associated pneumonia (RR=0.55, 95%CI 0.44 to 0.67, P<0.000 01), late-onset ventilator-associated pneumonia (RR=0.47, 95%CI 0.28 to 0.80, P=0.005), length of stay in intensive care unit (MD=−0.85, 95%CI −1.66 to −0.04, P=0.04) and rate of microbial colonization (RR=0.69, 95%CI 0.56 to 0.86, P=0.000 9). However, there were no significant differences between two groups in time to ventilator-associated pneumonia development (MD=0.96, 95%CI −0.21 to 2.12, P=0.11), length of mechanical ventilation (MD=−2.24, 95%CI −4.54 to 0.06, P=0.06), and rate of mortality (RR=0.88, 95%CI 0.73 to 1.05, P=0.15).ConclusionsCurrent evidence shows that compared with open tracheal suction system, closed tracheal suction system can reduce the incidence of ventilator-associated pneumonia and late-onset ventilator-associated pneumonia, shorten the hospital stay in intensive care unit, and reduce rate of microbial colonization. Due to limited quality and quantity of the included studies, more high quality studies are required to verify above conclusions.