Can carbon monoxide be separated from haemoglobin. If so, how is this possible?

Ok - this is as much as I understand it:

Carbon monoxide binds with haemoglobin to form carboxyhaemoglobin, which has a tighter binding than oxygen with haemoglobin, or oxyhaemoglobin. Therefore, the dissociation of carbon monoxide from haemoglobin is very slow. The only way to separate carboxyhaemoglobin is for it to be dissociated naturally - the rate of which is not fully understood.

As with many diffusions of gas, the diffusion of cabon monoxide into the blood (or the formation of carboxyhaemoglobin) reaches a saturation point after which diffusion and dissociation will occur interchangeably. Under the presence of high concentrations of oxygen, oxyhaemoglobin will eventually replace carboxyhaemoglobin.

Treatments of carbon monoxide-poisoned patients typically involve inhalation of high concentrations of oxygen through tightly fitted masks. This speeds up the replacemtnt of carboxyhaemoglobin with oxyhaemoglobin– since oxygen is a competitor of carbon monoxide.

If the patient is poisoned more significantly, they can be placed inside a pressure chamber with either pure oxygen at about twice the atmospheric pressure or a combination of oxygen and carbon dioxide. Higher pressures apparently speeds up replacement even more. Experiments show that a mix of oxygen and carbon dioxide speeds this up more so than pure oxygen does.

However, using pressure chambers seems to be a controversial treatment.

Last edited by Manabu Sakamoto (27th Feb 2007 13:40:53)

you are right that hyperbaric oxygen therapy is contraversial, though there is not much else that is proven to work for people with severe monoxide poisoning. When I was a junior doctor we tried free radical scavenger therapy to see if that would reduce the brain damage and thus the functional outocme, but we never got a large enough group of patients to make the results statistically significant and thus never wrote the study up!

regards

David