High-flow nasal cannula in the treatment of acute carbon monoxide poisoning: a pilot study

BACKGROUND: The first-line treatment in the Emergency Department (ED) for carbon monoxide (CO) poisoning is oxygen therapy via non-rebreathing face mask (NRFM). However, this method of oxygen delivery does not guarantee a fraction of inspired oxygen of 100%, as it should be desirable.METHODS: In this pilot prospective randomized clinical trial, we aimed at exploring the role of High-Flow Nasal Cannula (HFNC) in the treatment of patients admitted to the ED for CO poisoning in terms of reduction of carboxyhemoglobin (COHb) levels and neurological sequelae. Eight enrolled patients were randomly assigned to treatment with NRFM (N.=5) or HFNC (N.=3). Changes in COHb over the following 24 hours were monitored. Before ED discharge and at a 6-week follow-up visit, patients underwent a neurocognitive assessment.RESULTS: Baseline values of COHb were similar among the two groups (16.4 [13.4-22.0]% vs. 28.4 [25.9-29.4]%, for NRFM and HFNC, respectively; P=0.25). At ED discharge COHb levels were significantly lower compared to those at admission (0.9 [0.7-1.3]%, P=0.0065). At the Bayesian mixed model, the interaction of HFNC therapy with time emerged as a significant factor for reducing COHb levels (P=0.022), compared to NRFM. The neurocognitive evaluation did not show any significant difference between ED discharge and the follow-up visit in terms of neurological impairment.CONCLUSIONS: This pilot study demonstrates that oxygen therapy delivered through HFNC accelerates the reduction of COHb in patients with acute CO poisoning, compared to standard treatment. Such results should prompt a larger validation in the ED setting.