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

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 (HBO(2)). Opinions of hyperbaric medicine physicians regarding the treatment of such patients were also sought.

Records of patients treated with HBO(2) 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 HBO(2) treatment were selected for detailed analysis. Patient demographic data and information regarding circumstances of the poisoning, resuscitation, HBO(2) treatment, and subsequent course were extracted and collated. In addition, a postal survey of medical directors of North American HBO(2) treatment facilities regarding opinions about the management and outcome of such patients was performed.

A total of 18 patients were treated with HBO(2) 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 (10 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 10 of 18 patients. HBO(2) treatment was administered an average of 4.3 hours after poisoning (< or = 3 hours in 10 patients and < or = 6 hours in 15 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.

In this consecutive case series, cardiac arrest complicating CO poisoning was uniformly fatal, despite administration of HBO(2) 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.