Comparison of high-flow nasal cannula oxygen therapy and conventional reserve-bag oxygen therapy in carbon monoxide intoxication: A pilot study.

BACKGROUND: High-flow nasal cannula oxygen (HFNC) creates a positive pressure effect through high-flow rates compared to conventional oxygen therapy. The purpose of this human pilot study is to compare the effects of HFNC and conventional oxygen therapy on the rate of carbon monoxide (CO) clearance from the blood in patients with mild to moderate CO poisoning.

METHODS: CO-poisoned Patients randomly received 100% oxygen from a rebreathing reserve mask (NBO2 , flow of 15 L/min) or HFNC (flow of 60 L/min). The fraction of COHb value (fCOHb) was measured in 30-min intervals until it fell to under 10%. We determined the Half-life time of fCOHb (fCOHb t1/2 ).

RESULTS: A total of 22 patients had fCOHb levels ≥ 10% at the time of ED arrival, with 9 of them having fCOHb level ranging between 25% and 50%. There was no significant difference in the fCOHbt1/2 between the HFNC group and NBO2 group. However, the mean fCOHbt1/2 in the HFNC group (48.5 ± 12.4 min) has a smaller standard deviation than that in the NBO2 group (99.3 ± 93.38 min). There were significant between-group differences in the mean COHbt1/2 among the patients with fCOHb levels less than 25% (HFNC 43.6 ± 10.6 vs. NBO2 134.2 ± 111.3).

CONCLUSIONS: In this pilot randomized controlled trial study, HFNC therapy did not reduce fCOHbt1/2 compared to NBO2 therapy but could be beneficial in maintaining a constant fCOHbt1/2 as well as in reducing fCOHbt1/2 in mild CO poisoning patients compared to conventional NBO2 therapy. However, further studies with a larger number of patients are needed to establish HFNC therapy as an alternative therapy for CO poisoning patients.