High-Flow Nasal Cannula in Critically Ill Subjects With or at Risk for Respiratory Failure: A Systematic Review and Meta-Analysis.

High-flow nasal cannula (HFNC) oxygen delivery has been gaining attention as an alternative means of respiratory support for critically ill patients, with recent studies suggesting equivalent outcomes when compared with other forms of oxygen therapy delivery. The main objective of this review was to extract current data about the efficacy of HFNC in critically ill subjects with or at risk for respiratory failure. We performed a systematic review of publications (from database inception to October 2015) that evaluated HFNC in critically ill subjects with or at risk for acute respiratory failure and performed a meta-analysis comparing HFNC with noninvasive ventilation (NIV) and with standard oxygen therapy regarding major outcomes: incidence of invasive mechanical ventilation and ICU mortality. A total of 9 studies were included. HFNC was not associated with a reduction in the incidence of invasive mechanical ventilation compared with NIV (odds ratio [OR] 0.83, 95% CI 0.57-1.20, P = .31) or standard oxygen therapy (OR 0.49, 95% CI 0.22-1.08, P = .17). Additionally, HFNC use did not reduce ICU mortality compared with NIV (OR 0.72, 95% CI 0.23-2.21, P = .56) or with standard oxygen therapy (OR 0.69, 95% CI 0.33-1.42, P = .29). There was a trend toward better oxygenation compared with conventional oxygen therapy but a worse gas exchange compared with NIV. At this moment, HFNC therapy seems not to be superior to conventional oxygen therapy or NIV in terms of invasive mechanical ventilation rate or ICU mortality in critical illness, but new studies are needed to determine whether HFNC is associated with any difference in major outcomes when compared with other techniques.