Hypoxia and Medicine

why no changes in partial pressure of oxygen in the case of anemia hypoxia?

The hypoxemia definition as decreased partial pressure of oxygen excludes decreased oxygen content caused by anemia (decreased content of oxygen binding protein hemoglobin) or other primary hemoglobin deficiency, because they don't decrease the partial pressure of oxygen in blood. this is from wiki.. correct me if I'm wrong. 1) The Hb are independent towards partial pressure of oxygen. but why is that, since Hb decrease,less amount of oxygen carried.but no difference in partial pressure?

Public Comments

1. The question might be tough if it were comprehensible. Trying to understand you for 5 minutes and I give up. Hb is short for hemoglobin? MDs prefer Hgb.
2. Think of hypoxemia like a train and Hbg are the cars to carry oxygen. You either don't have enough cars or the cars are carrying something else, like CO. However, you need to look at the different types of hypoxemia. Causes are classified into groups: Low inspired partial pressure of oxygen (low PiO2)- from high altitudes Alveolar hypo-ventilation- dead space ventilation Impairment of diffusion across blood-gas membrane- from scar tissue forming in alveolar membranes Shunt- deoxygenated blood moves past alveoli without picking up oxygen Reduced mixed venous oxygen content in the context of a Shunt Also, if a patient has been in a hypoxic state for a long period of time, they will develop polycythemia. This adds cars to the train to help carry oxygen.