WOOT! Its time for a small lesson on the hypoxic drive now that I'm back! The hypoxic drive is the bodies backup system to control respiration. When the oxygen level falls, this system will also simulate breathing. Areas in the brain, the walls of the aorta, and the carotid arteries act as oxygen sensors. These sensors are easily satisfied by minimal levels of oxygen in the arterial blood which means that it is not as powerful as the carbon dioxide sensors in the brain stem. (Click Here to learn more on the Carbon Dioxide system) When the carbon dioxide sensors in the brainstem fail, this is when the hypoxic drive kicks in.

Abolition of hypoxia with oxygen therapy can reverse the compensatory hypoxic pulmonary vasoconstriction - leading to a much worse V/Q mismatch.