Carbon monoxide poisoning
Sources and clusters, why pulse oximetry misleads, co-oximetry and what the COHb level does and doesn't tell you, high-flow oxygen, the contested place of hyperbaric oxygen in Australia, cyanide in smoke inhalation, pregnancy and delayed neurological sequelae.
Tier 2Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- CO binds haemoglobin with about 240 times the affinity of oxygen, shifts the dissociation curve to the left and poisons mitochondrial cytochrome oxidase. The physiology is in oxygen and carbon dioxide transport.
- Think of it with headache, nausea or confusion in several people from one home, especially in winter.
- Pulse oximetry is normal. Diagnose with co-oximetry; a venous sample is fine.
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Sources
- Therapeutic Guidelines: Toxicology and Toxinology (December 2024 update: carbon monoxide oxygen and admission indications clarified)AU/NZTherapeutic Guidelines Limited, 2024
- Poisons Information Centre (13 11 26)AU/NZNSW Poisons Information Centre, Sydney Children's Hospitals Network
- Scheinkestel CD et al. Hyperbaric or normobaric oxygen for acute carbon monoxide poisoning: a randomised controlled clinical trial. Med J Aust 1999;170:203-10AU/NZMedical Journal of Australia, 1999
- Weaver LK et al. Hyperbaric oxygen for acute carbon monoxide poisoning. N Engl J Med 2002;347:1057-67New England Journal of Medicine, 2002
- Buckley NA et al. Hyperbaric oxygen for carbon monoxide poisoning. Cochrane Database Syst Rev 2011;(4):CD002041AU/NZCochrane, 2011
- Weaver LK et al. A randomized trial of one versus three hyperbaric oxygen sessions for acute carbon monoxide poisoning. Undersea Hyperb Med 2023Undersea and Hyperbaric Medical Society, 2023
- Fujita M et al. Evaluating the efficacy of hyperbaric oxygen therapy for acute carbon monoxide poisoning: a systematic review and meta-analysis. Acute Med Surg 2026Acute Medicine and Surgery, 2026
- Hampson NB et al. Practice recommendations in the diagnosis, management, and prevention of carbon monoxide poisoning. Am J Respir Crit Care Med 2012;186:1095-101American Journal of Respiratory and Critical Care Medicine, 2012
- ACEP Clinical Policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with acute carbon monoxide poisoning. Ann Emerg Med 2017;69:98-107American College of Emergency Physicians, 2017
- Cho DH et al. Practical recommendations for the evaluation and management of cardiac injury due to carbon monoxide poisoning. JACC Heart Fail 2024JACC Heart Failure, 2024
- Last updated
- 14 November 2026
What changed
- 14 November 2026 Personal emails, About story and Australian-style copy