ObjectiveTo assess the efficacy of subglottic secretion drainage for preventing ventilatorassociated pneumonia.MethodsData of relevant randomized controlled trials (RCT) from January 1991 to June 2010 were collected,and data were split into two groups,namely draining group and non-draining group.Meta analysis of ventilator-associated pneumonia was carried out for finding the incidence and mortality in patients with mechanical ventilation using the methods recommended by the Cochrane Collaboration.ResultsSeven RCTs met the inclusion criteria and 1647 patients were enrolled.Subglottic secretion drainage reduced the incidence of ventilator-associated pneumonia ( OR =0.45,95％ confidence interval [CI]:0.32 - 0.63 ),primarily by reducing early-onset pneumonia.But the mortalities of ventilator associated pneumonia were not significantly different between the two groups ( OR =1.03,95％ confi dence interval [CI]:0.75 - 1.41 ).ConclusionsSubglottic secretion drainage appeared effective in preventing ventilator associated pneumonia among patients expected to require ＞48 hours of mechanical ventilation,but the mortality was unchanged.