Asthma - Arterial Blood Gases
A more accurate and revealing, although more invasive, test of gas exchange by the lung is called an arterial blood gas. In this test, blood is obtained from an artery (commonly the radial artery at the wrist), allowing a more accurate test of not only the oxygen level but carbon dioxide. Carbon dioxide (CO2) is the waste product of the body excreted by the lungs. Severe degrees of lung disease, including asthma, can impair gas exchange mechanisms to the point that levels of CO2 will rise. In bronchial asthma this finding identifies an extremely severe and serious attack that requires hospitalization. These patients will also have lowered oxygen levels and may require mechanical respiratory assistance.
