Acute hypoxemic respiratory failure is among the leading causes of intensive care unit admission in adult patients, often leading to endotracheal intubation and invasive mechanical ventilation.¹ The current coronavirus disease 2019 (COVID-19) pandemic has further highlighted the importance of understanding the best approach to providing respiratory support for patients with respiratory failure. Invasive mechanical ventilation is associated with severe adverse events,² and avoiding unnecessary endotracheal intubation remains a major goal in the management of patients with acute hypoxemic respiratory failure.³ Multiple noninvasive oxygenation strategies have been developed to support oxygenation and ventilation that may lead to a reduced risk of endotracheal intubation and mortality. However, it remains unclear which of these is most effective.⁴

Background: Although small randomised controlled trials (RCTs) and observational studies have examined helmet noninvasive ventilation (NIV), uncertainty remains regarding its role. We conducted a systematic review and meta-analysis to examine the effect of helmet NIV compared to facemask NIV or high-flow nasal cannula (HFNC) in acute respiratory failure.Methods: We searched multiple databases to identify RCTs and observational studies reporting on at least one of mortality, intubation, intensive care unit (ICU) length of stay, NIV duration, complications or comfort with NIV therapy. We assessed study risk of bias using the Cochrane Risk of Bias 2 tool for RCTs and the Ottawa–Newcastle Scale for observational studies, and rated certainty of pooled evidence using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) framework.Results: We separately pooled data from 16 RCTs (n=949) and eight observational studies (n=396). Compared to facemask NIV, based on low certainty of evidence, helmet NIV may reduce mortality (relative risk 0.56, 95% CI 0.33–0.95) and intubation (relative risk 0.35, 95% CI 0.22–0.56) in both hypoxic and hypercapnic respiratory failure, but may have no effect on duration of NIV. There was an uncertain effect of helmet NIV on ICU length of stay and development of pressure sores. Data from observational studies were consistent with the foregoing findings but of lower certainty. Based on low and very low certainty data, helmet NIV may reduce intubation compared to HFNC, but its effect on mortality is uncertain.Conclusions: Compared to facemask NIV, helmet NIV may reduce mortality and intubation; however, the effect of helmet NIV compared to HFNC remains uncertain.