Take Home Points
- CO poisoning happens most often from common are accidental exposures from faulty home heaters, camp stoves and indoor use of gas powered generators, structure fires and intentional exposure like in suicide attempts.
- Patients with a mild exposure will present with symptoms like headache, nausea, vomiting, dizziness, vision blurring, palpitations, confusion or myalgias. More severe exposures may produce Altered mental status. seizures, coma, dysrythmias, myocardial ischemia, metabolic acidosis, syncope and vital sign abnormalities including hypotension and, eventually, cardiac arrest.
- To help distinguish the vague symptoms of a patient who may have chronic exposure ask about things like whether symptoms improve in different environments or whether they have sick pets, as human viral illness generally don’t affect our dogs and cats.
- If you’re concerned about CO send a co-ox panel. City dwellers may have a baseline carboxyhemoglobin of 1-2% and smokers around 6-10% but others should really have no carboxyhemoglobin.
- Treatment is supplemental O2 which can be stopped when symptoms improve. For severe symptoms and for pregnant patients, consider hyperbarics to prevent long term sequelae and to protect the fetus. As always, consider discussing the case with your local poison center to help decide whether a patient warrants transfer for hyperbarics.
LITFL: Carbon Monoxide Poisoning
EMCrit: Podcast 122 – Cardiac Arrest after the Toxicology of Smoke Inhalation with Lewis Nelson
FOAMcast: Episode #1: EMCrit Episode #122 – Cyanide and Carbon Monoxide Toxicity
Nelson LS, Hoffman RS: Inhaled Toxins, in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2010, (Ch) 159: p 2036-2045.
Tomaszewski C. Chapter 125. Carbon Monoxide. In: Nelson LS, Lewin NA, Howland M, Hoffman RS, Goldfrank LR, Flomenbaum NE. eds. Goldfrank’s Toxicologic Emergencies, 9e New York, NY: McGraw-Hill; 2011. Accessed April 19, 2017.