Objective This is a meta-analysis of the efficacy of noninvasive ventilation (NIV) with helmet compared to NIV with face mask in patients with acute respiratory failure (ARF). Methods " Helmet, face mask or facial mask” and " mechanical ventilation or noninvasive ventilation” were used as key words both in Chinese and English to search all the trials in PubMed, OVID, Embase, Scopus and Cochrane Library, websites, reference lists of articles, CNKI and Wanfang Database from inception to December 2016. Two reviewers independently assessed the methodological quality of the trials and extracted information. Revman 5.3 was used for data analysis. Results Ten randomized controlled trials (RCTs) and six case-control trials were included. NIV with a helmet reduced the intubation rate (OR=0.35, 95%CI 0.24 to 0.51, P<0.000 01), in-hospital mortality rate (OR=0.51, 95%CI 0.34 to 0.76, P=0.001), and NIV-related complications (OR=0.10, 95%CI 0.06 to 0.15, P<0.000 01) compared to NIV with face mask. There was no significant difference in gas exchange between two groups. In the subgroup analysis, types of ARF and ventilation mode did not affect the intubation rate and the complications relevant to NIV, but NIV with helmet mainly decreased the in-hospital mortality of the patients with hypoxemic ARF or pressure support ventilation. Conclusions NIV with a helmet can decrease the endotracheal intubation rate, in-hospital mortality, and NIV-related complications of the patients with ARF. And helmet is as effective as face mask in improving the gas exchange. However, larger or multicenter RCTs are needed to analyze the role of NIV with a helmet in this condition.
Objective To systematically review the efficacy of noninvasive positive pressure ventilation (NPPV) by helmet in adults with acute respiratory failure. Methods Randomized controlled trials (RCTs) or cohort studies about noninvasive positive pressure ventilation (NPPV) by helmet in adults with acute respiratory failure were retrieved in PubMed, The Cochrane Library (Issue 11, 2016), Web of Science, EMbase, CBM, CNKI and WanFang Data databases from inception to November 2016. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Stata 12.0 software was then used to perform meta-analysis. Results A total of eight studies were included. The results of meta-analysis showed that, NPPV by helmet could significantly reduce the carbon dioxide partial pressure (cohort study: SMD=–0.46, 95%CI –0.75 to –0.18, P=0.001), tracheal intubation rate (RCT: OR=0.36, 95%CI 0.17 to 0.77, P=0.008) and hospital mortality (RCT: OR=0.48, 95%CI 0.24 to 0.98, P=0.044), improve the positive end expiratory pressure (RCT: SMD=1.27, 95%CI 0.87 to 1.67, P<0.05) and respiratory status (RCT: SMD=–0.45, 95%CI –0.81 to –0.08,P=0.017). There was no significant difference in the duration of NPPV(cohort study: OR=–0.20, 95%CI –0.50 to 0.09, P=0.177; RCT: OR=–0.24, 95%CI –0.86 to 0.38, P=0.445). Conclusion NPPV by helmet can reduce the carbon dioxide partial pressure, tracheal intubation rate, hospital mortality and improve the positive end expiratory pressure, respiratory status. But the effects in the duration of NPPV and oxygenation index are uncertain. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify above conclusion.