Carboxyhemoglobin Information & Carboxyhemoglobin Links at HealthHaven.com

Carboxyhemoglobin (British English: Carboxyhaemoglobin) (COHb) is a stable complex of carbon monoxide and hemoglobin that forms in red blood cells when carbon monoxide is inhaled, and hinders delivery of oxygen to the body. Tobacco smoking (through carbon monoxide inhalation) raises the blood levels of COHb.

In large quantities, the effect of COHb is death - known medically as carboxyhemoglobinemia^[1] or carbon monoxide poisoning.^[2] However in smaller quantities COHb leads to oxygen deprivation of the body causing tiredness, dizziness and unconsciousness.

Hemoglobin binds to carbon monoxide preferentially compared to oxygen (approx 240:1)^[3], so effectively, COHb will not release the carbon monoxide, and therefore hemoglobin will not be available to transport oxygen from the lungs to the rest of the body. Humans should survive with very small amounts of COHb in their blood with very little or no observable effects.

COHb has a half-life in the blood of 4 to 6 hours, but this can be reduced to 40 minutes with administration of 100% oxygen. COHb increases risk of blood clot. It is thought that through this mechanism smoking increases the risk of having an ischemic stroke.

Pregnant smokers may give birth to babies of a lower birth mass as fetal hemoglobin takes up carbon monoxide more readily than in an adult, therefore the fetus of a smoker will suffer from mild hypoxia potentially retarding its development.

[edit] References

^ López-Herce J, Borrego R, Bustinza A, Carrillo A (September 2005). "Elevated carboxyhemoglobin associated with sodium nitroprusside treatment". Intensive Care Med 31 (9): 1235–8. doi:10.1007/s00134-005-2718-x. PMID 16041521. http://dx.doi.org/10.1007/s00134-005-2718-x.
^ Roth D, Hubmann N, Havel C, Herkner H, Schreiber W, Laggner A (July 2009). "Victim of Carbon Monoxide Poisoning Identified by Carbon Monoxide Oximetry". J Emerg Med. doi:10.1016/j.jemermed.2009.05.017. PMID 19615844. http://linkinghub.elsevier.com/retrieve/pii/S0736-4679(09)00407-7.
^ West JB: Respiratory Physiology -the essentials, 5th Ed. Williams & Williams, 1995, p. 76

[edit] External links

MeSH Carboxyhemoglobin

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[edit] References

[pmid16041521-0] López-Herce J, Borrego R, Bustinza A, Carrillo A (September 2005). "Elevated carboxyhemoglobin associated with sodium nitroprusside treatment". Intensive Care Med 31 (9): 1235–8. doi:10.1007/s00134-005-2718-x. PMID 16041521. http://dx.doi.org/10.1007/s00134-005-2718-x.

[pmid19615844-1] Roth D, Hubmann N, Havel C, Herkner H, Schreiber W, Laggner A (July 2009). "Victim of Carbon Monoxide Poisoning Identified by Carbon Monoxide Oximetry". J Emerg Med. doi:10.1016/j.jemermed.2009.05.017. PMID 19615844. http://linkinghub.elsevier.com/retrieve/pii/S0736-4679(09)00407-7.

[2] West JB: Respiratory Physiology -the essentials, 5th Ed. Williams & Williams, 1995, p. 76

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