5 ms·
However, the point of that study is that the oxygen levels are not 95%. The pulse oxymeter is wrong, and that study is about determining how wrong it is. The a
by slavik81 5y ago
However, the point of that study is that the oxygen levels are not 95%. The pulse oxymeter is wrong, and that study is about determining how wrong it is.
The abstract basically says you can subtract the blood carbon monoxide level from the pulse oxymeter's reported blood oxygen level to find the actual blood oxygen level. (They were a bit more precise than that, but it was very nearly one-to-one.)
A pulse oxymeter measures oxygen levels indirectly. It works by checking the colour of your blood. I suppose that the colour of carbon-monoxide poisoned blood must be similar to that of oxygenated blood. Perhaps because carbon monoxide attaches to blood cells in a similar way to pure oxygen.
- noduerme 5y agoRight - I get it. It can read over 95% in the absence of oxygen if carboxyhemoglobin tricks it out. I thought this might explain why during the pandemic, I could get a pulse ox reading of 85%, then smoke a cigarette and make the little bastard stop beeping.
- beowulfey 5y agoYes this is correct. Heme binds to CO in the same way it binds to O2–the iron is oxidized and has the same color. This is also the source of carbon monoxide toxicity, as it binds to CO tighter than O2.
- noduerme 5y agoYup. Same reason cyanide is deadly. Ain't chemistry grand? Good for a smoker to know since we're carrying quite a bit more than your average jogger... https://en.wikipedia.org/wiki/Carboxyhemoglobin#Affinity_of_hemoglobin_for_carbon_monoxide https://en.wikipedia.org/wiki/Carboxyhemoglobin#Affinity_of_...