Carbon Monoxide

[Qester]

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What happens to the oxygen dissociation curve when someone has carbon dioxide poisoning?

I'm finding conflicting information, some resources are saying it will cause a left shift, while others show that it mainly affects the Hb saturation (%), essentially decreasing Vmax.

Does anyone have any insight?

 

[DrPicard]

CO binds Hb which means less sites for O2 to bind --> decreased O2 content / decreased Hb saturation

CO binding to Fe in Hb also increases the affinity of the remaining Fe for O2 (cooperative kinetics) --> left shift of the O2-Hb dissociation curve

(Any time you see an S shaped curve, its cooperative/sigmoid kinetics at work)

 

[tasar1898]

CO poisoning is the worst thing that can happen in regards to oxygenation of peripheral tissues for 3 reasons :

1st , you get an anemia like O2 content in the blood since a lot of Hb just carries around CO instead of O2

2nd , your Hb curve is left shifted for the reasons explained above --> harder to unload the little O2 you may have

3rd , even if by miracle some O2 reaches the peripheral cells , it cant be used for OxPhos since the ETC is blocked by CO anyways..

 

[TraumaBlonde]

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[Qester]

Thanks for the responses!

 

[worldbeater]

If they happen to ask about the affinity of CO2 vs. O2 to Hb, it has a 200x more affinity and it is competitive/reversible. As the posters mentioned above, left shift means your holding on oxygen (whatever is left I guess), right shift of the curve means the hemoglobin is releasing O2 into the serum (measured by ABG/pO2)

 

[tasar1898]

@Qester thats the actual curve imo..

 

[Qester]

@Qester thats the actual curve imo..

Perfect, that was exactly what I thought would happen, but other sources were just showing a left curve