Carbon monoxide and oxygen delivery
Carbon monoxide poisoning reduces oxygen delivery to tissues because CO:
Answer B: explanation for every choice
A
CO causes a left shift, not a right shift.
B
Correct. CO occupies binding sites and makes the remaining O2 harder to unload.
C
Dissolved O2, the PaO2, can remain normal. The problem is carrying and unloading capacity.
D
CO does not lyse red cells.
TakeawayCO lowers O2-carrying capacity and hinders unloading, while PaO2 can stay normal.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb95.