Patients meeting certain criteria for acute hypercapnic respiratory failure should initially be treated with non-invasive ventilation (NIV) using bi-level positive pressure ventilation. Although NIV has been shown to decrease the need for endotracheal intubation, the number of deaths, and intensive care unit length of stay (LOS), its usage is generally constrained by patient intolerance and treatment failure. Therefore, an alternate treatment that this group of patients may better tolerate is a high-flow nasal cannula (HFNC).

Researchers looked for RCTs of persons with acute hypercapnic respiratory failure who were randomly allocated to receive HFNC or NIV by searching EMBASE, MEDLINE, and the Cochrane library from the databases’ creation to October 2021. Randomized trials’ potential for bias was evaluated using the Cochrane risk-of-bias tool. By employing a random-effects model, they estimated pooled relative risks (RR) for binary outcomes and mean differences (MD) for continuous outcomes, together with 95% CIs for each. In total, 8 randomized controlled trials (n=528) were incorporated into the meta-analysis. The primary outcome of death (RR 0.86, 95% CI 0.48-1.56, low certainty) and the secondary outcomes of endotracheal intubation (RR 0.80, 95% CI 0.46-1.39) and hospital length of stay (MD -0.82 days, 95% CI -1.83-0.20, high certainty) showed no significant difference between HFNC and NIV.

In terms of the change in carbon dioxide partial pressure, there was no significant difference between the groups (MD -1.87 mmHg, 95% CI -5.34-1.60, moderate certainty). Because of uncertainty and study heterogeneity, it is impossible to say if HFNC is better, worse, or about the same as NIV for patients with acute hypercapnic respiratory failure. Extra research into the effects of HFNC on this group is required.