Outcome of patients experiencing cardiac arrest with carbon monoxide poisoning treated with hyperbaric oxygen

Study objective: We sought to examine the outcome of a subgroup of patients with extreme carbon monoxide (CO) poisoning, specifically those discovered in cardiac arrest, resuscitated, and subsequently treated with hyperbaric oxygen (HBO2). Opinions of hyperbaric medicine physicians regarding the treatment of such patients were also sought. Methods: Records of patients treated with HBO2 for acute CO poisoning at Virginia Mason Medical Center in Seattle from September 1987 to August 2000 were reviewed. Those who were resuscitated from cardiac arrest in the field before HBO2 treatment were selected for detailed analysis. Patient demographic data and information regarding circumstances of the poisoning, resuscitation, HBO2 treatment, and subsequent course were extracted and collated. In addition, a postal survey of medical directors of North American HBO2 treatment facilities regarding opinions about the management and outcome of such patients was performed. Results: A total of 18 patients were treated with HBO2 after resuscitation from CO-associated cardiac arrest. They included 10 female and 8 male patients ranging in age from 3 to 72 years. Sources of CO included house fires (18 patients) and automobile exhaust (8 patients). Patient carboxyhemoglobin levels averaged 31.7%+/- 11.0% (mean +/- SD), and arterial pH averaged 7.14 +/-0.19. Presenting cardiac rhythm was a bradydysrhythmia in 18 of 18 patients. HBO2 treatment was administered an average of 4.3 hours after poisoning (less than or equal to3 hours in 10 patients and less than or equal to6 hours in 25 patients). Despite this, all 18 patients died during their hospitalizations. Medical directors of hyperbaric treatment facilities estimated a 74% likelihood of survival for a hypothetical patient with this presentation. Conclusion: In this consecutive case series, cardiac arrest complicating CO poisoning was uniformly fatal, despite administration of HBO2 therapy after initial resuscitation. Survey results suggest that physician education regarding this subset of CO-poisoned patients is needed. The prognosis of this condition should be considered when making triage and treatment decisions for patients poisoned to this severity.