Humidified oxygen via a high flow nasal cannula (HFNC) is a form of supplemental oxygen therapy that has significant theoretical advantages over conventional oxygen therapy (COT). However, the clinical role of HFNC in acute hypoxemic respiratory failure (AHRF) has not been well established. This review compares the efficacy of HFNC with COT and non-invasive ventilation (NIV) in patients with AHRF.

Studies reviewed were selected based on relevance from a systematic literature search conducted in Medline and EMBASE to include all published original research through May 2016. Twelve studies matched the inclusion criteria.

In the majority of the studies, HFNC was associated with superior comfort and patient tolerance as compared to NIV or COT. HFNC was associated with reduced work of breathing in comparison with COT in some, but not all, studies in the review. COT and NIV were associated with a higher 90-day mortality rate compared to HFNC in only one multicenter randomized trial versus no mortality difference reported by others. Three out of four studies demonstrated a decreased need for escalation of oxygen therapy with HFNC. Six out of eight studies demonstrated improved oxygenation with HFNC as compared to COT. Two of three studies revealed worse oxygenation with HFNC as compared to NIV.

This review suggests that HFNC may be superior to COT in AHRF patients in terms of oxygenation, patient comfort, and work of breathing. It may be reasonable to consider HFNC as an intermediate level of oxygen therapy between COT and NIV.