High-Flow Oxygen Therapy in Acute Respiratory Failure

OBJECTIVE: To compare the comfort of oxygen therapy via high-flow nasal cannula (HFNC) versus via conventional face mask in patients with acute respiratory failure. Acute respiratory failure was defined as blood oxygen saturation < 96% while receiving a fraction of inspired oxygen ≥ 0.50 via face mask.

METHODS: Oxygen was first humidified with a bubble humidifier and delivered via face mask for 30 min, and then via HFNC with heated humidifier for another 30 min. At the end of each 30-min period we asked the patient to evaluate dyspnea, mouth dryness, and overall comfort, on a visual analog scale of 0 (lowest) to 10 (highest). The results are expressed as median and interquartile range values.

RESULTS: We included 20 patients, with a median age of 57 (40–70) years. The total gas flow administered was higher with the HFNC than with the face mask (30 [21.3–38.7] L/min vs 15 [12–20] L/min, P < .001). The HFNC was associated with less dyspnea (3.8 [1.3–5.8] vs 6.8 [4.1–7.9], P = .001) and mouth dryness (5 [2.3–7] vs 9.5 [8–10], P < .001), and was more comfortable (9 [8–10]) versus 5 [2.3–6.8], P < .001). HFNC was associated with higher P_aO2 (127 [83–191] mm Hg vs 77 [64–88] mm Hg, P = .002) and lower respiratory rate (21 [18–27] breaths/min vs 28 [25–32] breaths/min, P < .001), but no difference in P_aCO2.

CONCLUSIONS: HFNC was better tolerated and more comfortable than face mask. HFNC was associated with better oxygenation and lower respiratory rate. HFNC could have an important role in the treatment of patients with acute respiratory failure.