title: Helmet CPAP versus Oxygen Therapy in Hypoxemic Acute Respiratory Failure: A Meta-Analysis of Randomized Controlled Trials.
abstract: OBJECTIVE
  The efficacy of helmet continuous positive airway pressure (CPAP) in hypoxemic acute respiratory failure (hARF) remains unclear. The aim of this meta-analysis was to critically review studies that investigated the effect of helmet CPAP on gas exchange, mortality, and intubation rate in comparison with standard oxygen therapy.
  
  
  METHODS
  We performed a meta-analysis of randomized controlled trials (RCTs) by searching the PubMed, Embase, Cochrane library, OVID, and CBM databases, and the bibliographies of the retrieved articles. Studies that enrolled adults with hARF who were treated with helmet CPAP and measured at least one of the following parameters were included: gas exchange, intubation rate, in-hospital mortality rate.
  
  
  RESULTS
  Four studies with 377 subjects met the inclusion criteria and were analyzed. Compared to the standard oxygen therapy, helmet CPAP significantly increased the PaO₂/FiO₂ [weighted mean difference (WMD)=73.40, 95% confidence interval (95% CI): 43.92 to 102.87, p<0.00001], and decreased the arterial carbon dioxide levels (WMD=-1.92, 95% CI: -3.21 to -0.63, p=0.003), intubation rate [relative risk (RR)=0.21, 95% CI: 0.11 to 0.40, p<0.00001], and in-hospital mortality rate (RR=0.22, 95% CI: 0.09 to 0.50, p=0.0004).
  
  
  CONCLUSIONS
  The results of this meta-analysis suggest that helmet CPAP improves oxygenation and reduces mortality and intubation rates in hARF. However, the significant clinical and statistical heterogeneity of the literature implies that large RCTs are needed to determine the role of helmet CPAP in different hypoxemic ARF populations.
authors.affiliation: Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yuwen
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Li
authors.affiliation: The State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, Guangzhou Medical University, Guangzhou, China.
authors.forename: Luqian
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yitai
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Respiratory Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, China. chen_xin1020@163.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
mesh_terms: D000208:Acute Disease; D000328:Adult; D045422:Continuous Positive Airway Pressure; D017052:Hospital Mortality; D006801:Humans; D010102:Oxygen Inhalation Therapy; D016032:Randomized Controlled Trials as Topic; D012131:Respiratory Insufficiency / Q000401:mortality / Q000628:therapy*
keywords: Helmets; continuous positive airway pressure; endotracheal intubation; meta-analysis; mortality; respiratory failure