Randomized Controlled Trial of Humidified High-Flow Nasal Oxygen for Acute Respiratory Distress in the Emergency...

Humidified high-flow nasal cannula (HFNC) is a novel method of oxygen delivery with increasing use in emergency departments and intensive care settings despite little evidence showing benefit over standard oxygen delivery methods (standard O2). The aim of this study was to determine whether HFNC compared with standard O2 given to subjects in acute respiratory distress would reduce the need for noninvasive ventilation or invasive ventilation.

This was a pragmatic open randomized controlled trial in adult subjects with hypoxia and tachypnea presenting to a tertiary academic hospital emergency department. The primary outcome was the need for mechanical ventilation in the emergency department.

We screened 1,287 patients, 322 met entry criteria and 19 were excluded from analysis. Of these, 165 randomized to HFNC and 138 to standard O2 were analyzed. Baseline characteristics were similar. In the HFNC group, 3.6% (95% CI 1.5-7.9%) versus 7.2% (95% CI 3.8-13%) in the standard O2 group required mechanical ventilation in the emergency department (P = .16), and 5.5% (95% CI 2.8-10.2%) in HFNC versus 11.6% (95% CI 7.2-18.1%) in the standard O2 group required mechanical ventilation within 24 h of admission (P = .053). There was no difference in mortality or stay. Adverse effects were infrequent; however, fewer subjects in the HFNC group had a fall in Glasgow coma score due to CO2 retention, 0% (95% CI 0-3%) versus 2.2% (95% CI 0.4-6%). One in 12 subjects did not tolerate HFNC.

HFNC was not shown to reduce the need for mechanical ventilation in the emergency department for subjects with acute respiratory distress compared with standard O2, although it was safe and may reduce the need for escalation of oxygen therapy within the first 24 h of admission.