Effect of Carbon monoxide on oxygen transport

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EFFECT OF CARBON MONOXIDE ON OXYGEN TRANSPORT

WHAT IS IT?

Carbon Monoxide, CO, is formed when a carbon containing compound burns incompletely

Haemoglobin combines very readily, and almost irreversibly, with carbon monoxide. It combines with CO 250 times more readily than it does with oxygen.

Carbon monoxide readily diffuses across the walls of the alveoli, into the blood, and into the red blood cells. Here it combines with the haem groups in the haemoglobin molecules, forming carboxyhaemoglobin. Carboxyhaemoglobin is a very stable compund; CO remains combined with haemoglobin for a long time

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Oxygen and Carbon Monoxide dissociation curves plotted together give a clear picture of the alarming affinity between Hb and CO

Low concentrations of CO, as low as 0.1% of the air, can cause death by asphyxiation.

Treatment of CO poisoning involves administration of a mixture of pure oxygen and carbon dioxide: high concentrations of oxygen to favour the combination of haemoglobin with oxygen rather than carbon monoxide, and carbon dioxide to stimulate an increase in breathing rate.

Cigarette smoke contains up to 5% Carbon monoxide.

Around 5% of the haemoglobin in a regular smoker's blood is permanently combined with carbon monoxide.