Why does hematocrit values rise in chronic obstructive pulmonary disease?

Answer 1

COPD is characterized by aveolar destruction. Funstional alveoli are necessary for the transport of oxygen from the atmosphere into the blood stream and eventually to the tissues. Loss of alveoli equals loss of oxygen in the tissues and incidently increase in carbon dioxide in the same since it cannot be excreted into the lungs. The end consumer of oxygen is the target tissue. The tissue merely registers that oxygen levels are low, but cannot differentiate as to whether they are low for lack of oxygen transport capacity or lack of oxygen to be transported. Hemoglobin is a molecule that binds oxygen in the bloodstream. It is responsible for the delivery of a majority of the oxygen that reaches the target tissue. Since an organism is not necessarily able to alter the external environment that it is in, i.e. the oxygen that is available to it, it attempts to increase it's ability to transport the oxygen that is available, i.e., it increases the concentration of hemoglobin in it's bloodstream. Hope that this helps. PTR

Answer 2

It is the body's attempt to overcome the lack of Oxygen getting to its Cells. Having more hemoglobin to carry Oxygen is one way to do that. Unfortunately, the real problem, when there is COPD, is in the lungs and not in the Blood.

Answer 3

Oxygen is essential for life. In severe obstructive lung disease the lungs are so bad that the normal amount of oxygen cannot reach the blood stream to be delivered around the body. Oxygen in the blood is carried by Hemoglobin the amount of which is measured by the hematocrit. In severe obstructive lung disease the body adjusts to the reduced amount of oxygen reaching the blood from the lungs by producing more hemoglobin which compensates for the failure of the lungs to transfer the full amount of oxygen. This extra hemoglobin is measured in a raised hematocrit. It is a mechanism whereby the supply of oxygen to the body can be maintained even when the lungs are bady diseased. While it does help in some ways in others it can be counter productive causing for example the heart to have to work much harder and consequently be under some strain. It should be noted these events only occur with severe disease.