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carboxyhemoglobin
Hemoglobin with carbon monoxide (CO) bound to heme.
Pathology:
- CO competively binds to heme
- it also shifts the oxygen dissociation curve to the left (diminished release of O2)
- the 1/2 life of carboxyhemoglobin is 5 hours on room air
- susceptible organs include brain, heart & to a lesser extent kidney
- see carbon monoxide poisoning
Laboratory:
- may cause falsely elevated SaO2 on pulse oximetry
- arterial blood gas with blood carboxyhemoglobin levels
Complications:
- up to 1 year later, patients may develop neurologic evidence of CO poisoning
Management:
1) levels < 25%, 100% O2
2) levels > 25%: hyperbaric O2 [1]
3) levels > 40%, risk of anoxic brain damage
4) rule out myocardial infarction
Related
carbon monoxide poisoning
carboxyhemoglobin in blood
General
hemoglobin
Properties
COMPARTMENT: cytoplasm
CELL: erythrocyte
SUBUNITS: hemoglobin alpha chain
:QUANTITY 2
hemoglobin beta chain
:QUANTITY 2
MISC-INFO: 1/2life 5 HOURS
References
- Medical Knowledge Self Assessment Program (MKSAP) 18,
American College of Physicians, Philadelphia 2018