Hypemic Hypoxia

Hypemic Hypoxia

When blood cannot supply enough oxygen to all the cells in our body it is called hypemic hypoxia. 

The oxygen deficiency is not caused by a lack of inhaled oxygen from the atmosphere. Severe bleeding (reduced blood volume), certain blood diseases (anemias), smoking (carbon monoxide ), altitude and whole blood donations (lack of red blood cells in sufficient numbers) are conditions that may occur to cause the lack of oxygen for normal functioning. Carbon monoxide presence is the most common and affects a blood molecule called hemoglobin.

Hypemic hypoxia is the result of hemoglobin that can't  chemically bind oxygen molecules. Why can't they bind the oxygen?

Engines produce a colorless, odorless  gas named carbon monoxide (CO). It provides the competition for the oxygen binding sites on the hemoglobin molecule when it is present in the air you breath inside the cockpit. In automobiles, an additive is added to the gasoline they burn that warns the occupants that exhaust fumes exist inside the car that contains carbon monoxide molecules. If you ignore the warnings, and fail to open windows for proper ventilation, your blood hemoglobin binding sites are occupied by carbon monoxide rather than oxygen. Remember carbon monoxide has a much greater attraction for hemoglobin than oxygen.

The affinity of carbon monoxide for hemoglobin binding sites is twenty times that of oxygen. It creates an unfair disadvantage for oxygen. Oxygen loses the binding site competition and you can lose you life if you don't respond to the warnings that carbon monoxide is present in your car or planes passenger compartment.

Your plane engine, through the mixture control, is adjustable to eliminate most of the unburned fuel. When you back off on the mixture control by 25 to 50 degrees, the presence of carbon dioxide is there, but virtually undetectable by your sense of smell.

Since the carbon monoxide is twenty times more likely to bind to oxygen the net result of the exhaust leak into a planes interior is you become unconscious before you detect the exhaust leak. If you can't respond the plane will crash.

You may read stories, periodically, about young couples found dead in "Lovers Lanes" because of carbon monoxide poisoning. It is unmistakeable,  because the skin is bright red from carbon monoxide  when the couple is found.

There is a fix. There are carbon monoxide detectors, on the market, that provide visual indications or beep a loud, distinctive sound, or both, that carbon monoxide is present.

You respond by increasing the fresh air ventilation. You just prevented a life threatening event from happening by responding, with knowledge. The correct fix is fresh air immediately to refresh your body with the oxygen it requires. 

Hypoxia takes many forms and you just found a very important way to avoid hypoxia in aircraft.