No Mandate for Hyperbaric Therapy in CO Poisoning

The new year – actually, the end of the old year – brings us a new update on the management of carbon monoxide poisoning, as distilled into an ACEP Clinical Policy statement. There are three elements to their update, addressing specific management questions in the context of carbon monoxide toxicity:

• Don’t rely exclusively on non-invasive means for CO measurement.
• Hyperbaric oxygen therapy is neither proven nor disproven of benefit.
• Cardiac testing provides useful prognostic information.

The most impactful recommendation of the three is the one for HBO therapy, which is either dismissed out-of-hand or pursued with such zealotry that eligible patients are airlifted to far-flung dive chambers for treatment. In theory, HBO therapy helps reduce the delayed neuropathology and cognitive burden related to lipid peroxidation and other toxic metabolites. However, these authors appropriately synthesize the low-quality evidence into a conclusion that HBO therapy has no proven advantage to high-flow oxygen.

As with any therapy for which the evidence is poor, there are proponents on both sides and substantial practice variation. This Clinical Policy does not state HBO is inappropriate or not beneficial for carbon monoxide poisoning, merely the evidence is inconclusive. Sometimes, when the evidence is insufficient to provide an answer, the magnitude of benefit is small or clinically unimportant. In this case, I’m not even sure such a conclusion regarding the scope of benefit can be made – the foundational evidence is simply too unreliable to make any practice-influencing recommendations.

“Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Acute Carbon Monoxide Poisoning”
https://www.ncbi.nlm.nih.gov/pubmed/27993310