title: Impact of closed versus open tracheal suctioning systems for mechanically ventilated adults: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Whether closed tracheal suctioning systems (CTSS) reduce the incidence of ventilator-associated pneumonia (VAP) compared with open tracheal suctioning systems (OTSS) is inconclusive. We conducted a systematic review and meta-analysis of randomized controlled trials that compared CTSS and OTSS.
  
  
  METHODS
  PubMed, the Cochrane Central Register of Controlled Trials, the Web of Science, Google Scholar, and a clinical trial registry from inception to October 2014 were searched without language restrictions. Randomized controlled trials of CTSS and OTSS that compared VAP in mechanically ventilated adult patients were included. The primary outcome was the incidence of VAP. Secondary outcomes were mortality and length of mechanical ventilation. Data were pooled using the random effects model.
  
  
  RESULTS
  Sixteen trials with 1,929 participants were included. Compared with OTSS, CTSS was associated with a reduced incidence of VAP (RR 0.69; 95 % CI 0.54-0.87; Q = 26.14; I (2) = 46.4 %). Compared with OTSS, CTSS was not associated with reduction of mortality (RR 0.96; 95 % CI 0.83-1.12; Q = 2.27; I (2) = 0.0 %) or reduced length of mechanical ventilation (WMD -0.45 days; 95 % CI -1.25 to 0.36; Q = 6.37; I (2) = 5.8 %). Trial sequential analysis suggested a lack of firm evidence for 20 % RR reduction in the incidence of VAP. The limitations of this review included underreporting and low quality of the included trials, as well as variations in study procedures and characteristics.
  
  
  CONCLUSIONS
  Based on current, albeit limited evidence, it is unlikely that CTSS is inferior to OTSS regarding VAP prevention; however, further trials at low risk of bias are needed to confirm or refute this finding.
authors.affiliation: Department of General Medicine, Kurashiki Central Hospital, 1-1-1 Miwa, Kurashiki, Okayama, 710-8602, Japan, nrk40448@nifty.com.
authors.forename: Akira
authors.initials: A
authors.lastname: Kuriyama
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Umakoshi
authors.forename: Jun
authors.initials: J
authors.lastname: Fujinaga
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Takada
mesh_terms: D006801:Humans; D016032:Randomized Controlled Trials as Topic; D012121:Respiration, Artificial; D013183:Sputum; D013396:Suction / Q000379:methods*; D014132:Trachea