title: [Effect of noninvasive ventilation on hypercapnic encephalopathy syndrome: a Meta-analysis].
abstract: OBJECTIVE
  To evaluate the effect of noninvasive ventilation (NIV) on hypercapnic encephalopathy syndrome (HES) induced by acute exacerbation of chronic obstructive pulmonary disease (AECOPD).
  
  
  METHODS
  An extensive search of related literature from the PubMed, EMBASE, Cochrane library, CNKI and Wanfang databases up to January 2015 was performed. Randomized controlled trials (RCTs) and case control studies regarding comparison of the effect of NIV and conventional mechanical ventilation (CMV) on the HES were collected. Critical appraisal skills program (CASP) was adopted to assess the quality of the studies. Data including mortality, trachea intubation rate, duration of mechanical ventilation and complication rate were collected, and Meta-analysis was performed by RevMan 5.3.
  
  
  RESULTS
  Finally, 6 studies were included with 225 subjects, among whom 112 were in NIV group and 113 in CMV group, and the average Kelly-Matthay score was 3. Compared with CMV group, the mortality [20.5% (23/112) vs. 32.7% (37/113), risk ratio (RR) = 0.63, 95% confidential interval (95%CI) = 0.40-0.98, P = 0.04], intubation rate [35.7% (40/112) vs. 100.0% (113/113), RR = 0.38, 95%CI = 0.26-0.55, P < 0.000?01], incidence of ventilation related complications [26.2% (21/80) vs. 50.6% (42/83), RR = 0.52, 95%CI = 0.34-0.79, P = 0.002] in NIV group were significantly decreased, and the duration of mechanical ventilation was significantly shortened [days: 7.1 vs. 16.2, standard mean difference (SMD) = -0.93, 95%CI = -1.39 to -0.46, P < 0.000?1].
  
  
  CONCLUSIONS
  NIV could significantly lower the mortality rate, intubation rate, and complications in the treatment of HES induced by AECOPD under close monitoring.
authors.affiliation: Department of Respiratory and Critical Care Medicine, the First Affiliated Hospital of Zhengzhou University, Henan Provincial Clinical Medicine Key Laboratory, Zhengzhou 450052, Henan, China (Liu Q, Jia LQ, Cheng Z); State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, Guangdong, China (Chen RC). Corresponding author: Liu Qi, Email: qi.liu@vip.163.com.
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.forename: Rongchang
authors.initials: R
authors.lastname: Chen
authors.forename: Liuqun
authors.initials: L
authors.lastname: Jia
authors.forename: Zhe
authors.initials: Z
authors.lastname: Cheng
mesh_terms: D000208:Acute Disease; D001927:Brain Diseases; D016022:Case-Control Studies; D006801:Humans; D007442:Intubation, Intratracheal; D063087:Noninvasive Ventilation; D029424:Pulmonary Disease, Chronic Obstructive; D016032:Randomized Controlled Trials as Topic; D012121:Respiration, Artificial