ORIGINAL ARTICLE Subglottic secretion drainage for preventing ventilator-associated pneumonia: An updated meta-analysis of randomized controlled trials Fei Wang, MD, Lulong Bo, MD, Lu Tang, PhD, Jingsheng Lou, MD, Youping Wu, MD, Feng Chen, MD, Jinbao Li, MD, PhD, and Xiaoming Deng, MD, PhD, Shanghai, China BACKGROUND: Subglottic secretion drainage (SSD) has been shown to be associated with a lower incidence of ventilator-associated pneumonia (VAP) in a previous meta-analysis. However, a number of randomized controlled trials (RCTs) have been published since then, and so we aimed to conduct an updated meta-analysis. METHODS: A systematic literature search of Pubmed, Embase, and Cochrane Central Register of Controlled Trials was conducted using specific search terms. Eligible studies were RCTs that compared SSD with standard endotracheal tube care in mechanically ventilated adult patients. RESULTS: Ten RCTs with 2,213 patients were identified. SSD significantly reduced incidence of VAP (relative risk [RR] = 0.56, 95% confidence interval [CI]: 0.45– 0.69, p  0.00001) and early-onset VAP (RR = 0.23, 95% CI: 0.13– 0.43, p  0.00001), shortened ventilation duration by 1.55 days (95% CI: -2.40 to -0.71 days, p = 0.0003), and prolonged time to VAP by 3.90 days (95% CI: 2.56 –5.24 days). Subgroup analyses suggested a significant reduction in incidence of VAP when stratified by intermittent (RR = 0.49, 95% CI: 0.34 – 0.71, p = 0.0001) and continuous SSD (RR = 0.61, 95% CI: 0.46 – 0.79, p = 0.0003). No significant differences were observed regarding incidence of late-onset VAP, overall mortality, or length of intensive care unit or hospital stay. CONCLUSIONS: This updated meta-analysis confirmed that SSD was beneficial in preventing VAP. Furthermore, the effect of SSD on late-onset VAP, comparison between intermittent and continuous SSD, and safety of SSD in mechanically ventilated patients should be evaluated in future RCTs. (J Trauma. 2012;72: 1276 –1285. Copyright © 2012 by Lippincott Williams & Wilkins) LEVEL OF EVIDENCE: I, meta-analysis. KEY WORDS: Subglottic secretion drainage; ventilator-associated pneumonia; critical care; systematic review. V entilator-associated pneumonia (VAP) remains a leading cause of morbidity and mortality among mechanically ventilated patients, with the incidence ranging from 9% to 27% and a crude mortality of 25% to 50% 1–4 and is associ- ated with prolonged hospital stay 2,5,6 and increased cost. 7 To date, studies have confirmed that subglottic secre- tions pooling above the endotracheal cuff provide an impor- tant mechanism for bacterial proliferation. The translocation of these secretions past the endotracheal tube cuff and into the lung parenchyma contributes to the development of VAP. 8 –12 Therefore, a potential strategy of preventing VAP is to remove these secretions by subglottic secretion drainage (SSD), which is accomplished through a separate dorsal lumen that opens directly above the endotracheal tube cuff. Since its introduction into medical practice, many studies have examined the efficacy and effectiveness of SSD in preventing VAP. A previous meta-analysis published in 2005 by Dezfulian et al. 13 suggested that SSD seemed to be effective in preventing early-onset VAP among patients ex- pected to require mechanical ventilation (MV) of 72 hours. However, the number of original studies addressing this topic has doubled since then. It is necessary to update the meta- analysis, which might provide more solid evidence and minimize potential bias caused by limited publications. Therefore, we performed an updated meta-analysis to inves- tigate the effect of SSD in preventing VAP including early- and late-onset VAP and secondary clinical outcomes. MATERIALS AND METHODS We followed the PRISMA guideline for reporting our meta-analysis. 14 Search Strategy Related articles in all languages were identified and selected by searching Pubmed, Embase, and the Cochrane Central Register of Controlled Trials (December 10, 2010), Submitted: July 15, 2011, Revised: December 17, 2011, Accepted: December 21, 2011. From the Department of Anesthesiology (F.W., L.B., J.Lou, Y.W., F.C., J.Li, X.D.), Changhai Hospital, Second Military Medical University, Shanghai; and Department of Anesthesiology (L.T.), General Hospital of Jinan Military Command, Jinan, China. Supported by grant from the National Natural Science Foundation of China (No. 30872454). The first three authors contributed equally to this study. Address for reprints: Xiaoming Deng, MD, PhD, or Jinbao Li, MD, PhD, Department of Anesthesiology, Changhai Hospital, Second Military Medical University, Shanghai 200433, People’s Republic of China; email: deng_x@ yahoo.com or lijinbaoshanghai@163.com. DOI: 10.1097/TA.0b013e318247cd33 1276 J Trauma Volume 72, Number 5