ABSTRACT
Any disease affecting the lungs will ultimately affect gas exchange, initially by lowering of arterial oxygen tensions and, in more advanced disease, particularly COPD, increasing the carbon dioxide tension. In a broader context, such primary lung disease will adversely affect coexisting illnesses, such as cardiac disease (congestive heart failure, angina), hema tological conditions (sickle cell anemia), peripheral vascular disease with claudication, etc. The hypoxemia due to lung disease will reduce oxygen delivery to any organ system compromised by another disease process and either require adjustments or produce a wors ening of symptoms.
