Use of hyperbaric oxygen therapy for preventing delayed neurological sequelae in patients with carbon monoxide poisoning: A multicenter, prospective, observational study in Japan.

Background: The purpose of this study was to clarify the practical clinical treatment for acute carbon monoxide (CO) poisoning in Japan and to investigate the efficacy of hyperbaric oxygen (HBO₂) therapy in preventing delayed neurological sequelae (DNS) in the acute phase of CO poisoning. Methods: We conducted a multicenter, prospective, observational study of acute CO poisoning in Japan. Patients with acute CO poisoning were enrolled and their treatment details were recorded. The primary endpoint was the onset of DNS within 2 months of CO exposure. Factors associated with DNS were assessed with logistic regression analysis. Results: A total of 311 patients from 57 institutions were registered and 255 were analyzed: 171 received HBO₂ therapy (HBO₂ group) and 84 did not (normobaric oxygen [NBO₂] group). HBO₂ therapy was performed zero, once, twice, or three times within the first 24 h in 1.8%, 55.9%, 30.9%, and 11.3% of the HBO₂ group, respectively. The treatment pressure in the first HBO₂ session was 2.8 ATA (47.9% of the HBO₂ group), 2.0 ATA (41.8%), 2.5 ATA (7.9%), or another pressure (2.4%). The incidence of DNS was 13/171 (7.6%) in the HBO₂ group and 3/84 (3.6%) in the NBO₂ group (P = 0.212). The number of HBO₂ sessions in the first 24 h was one of the factors associated with the incidence of DNS (odds ratio, 2.082; 95% confidence interval, 1.101–3.937; P = 0.024). Conclusions: The practical clinical treatment for acute CO poisoning, including HBO₂ therapy, varied among the institutions participating in Japan. HBO₂ therapy with inconsistent protocols showed no advantage over NBO₂ therapy in preventing DNS. Multiple HBO₂ sessions was associated with the incidence of DNS. [ABSTRACT FROM AUTHOR]