Smoke without fire

It’s 2am, you’re just catching up on the waiting room an things are beginning to settle when one of the many bat phones in the department rings to alert you to the imminent arrival of a 75 year old man from a house fire. No details but he’s  sick as.

What runs through your head at this point?

Click for answer

Whats the deal with CO poisoning

Want to know more on Carbon Monoxide (CO) Toxicity

How does CO make you sick

So how do I tell if someone as CO poisoning

Do I need an arterial sample

How do I treat it


Case Outcome



About Andy Neill

EM Reg/Resident based near Dublin. Former anatomy lecturer, theology student and occasional musician @andyneill | + Andy Neill | Contact


  1. Hey Andy,

    Great summary, particularly in the day that’s in it. Hopefully Pun won’t need to quickly read this tonight!

    Just wondering, did this man get transferred to our friendly burns centre?

  2. Nice case Andy! Just about the sats….surely the sats (if the oxyHb and carboxyHb are indistinguishable on the oximeter) should be normal, unless there was hypoxia from something else like a low Fi02 , bronchospasm. or airway obstruction.

    Cheers Vinnie

    • The blood gas machine measures the different hb using co oximetry. It can tell the difference between COHb and oxyHb.

      The sats probe can only tell the difference between oxyHb and deoxyHb.

      So effectively this pt had carboxyhb of 47% and oxyHb of 53%. The sats probe was reading sats in the 80s.

  3. I’d add that you shuold probably give sodium thiosulfate if cyanide poisoning is suspected with hydroxocobalamin. The thiosulfate takes cyanide and makes thiocyanide which is excreted in the urine and plays no role in worsening a patient’s likely concurrent metHb like amyl or sodium nitrite.

  4. You can get to 100% FiO2 with pseudo-NRB by going past the last past the 15L marker to up to 30-60L/min. At least thats what that Levitan/Weingart Annals article stated.


  1. […] Author: Andy Neill of Emergency Medicine Ireland.   "smoke inhalation is the major killer in house fires NOT the burns. It’s easy to get distracted by impressive looking major burns and forget about the invisible little toxicites killing your patient."   Question and answer format enables quick review of the major issues to consider.  […]

  2. […] Hyperbaric oxygen therapy for acute domestic carbon monoxide poisoning: […]

  3. […] Smoke without fire — Great review on managing CO poisoning! Definitely worth a read! […]

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