ABSTRACT
Oxygen can be measured most simply by use of a pulse oximeter. A finger clip is applied to the finger and the oxygen saturation in the blood is measured (as a percentage). It cannot measure carbon dioxide. Below 92% a very small decrease in the oxygen tension in the blood causes a very rapid fall in the oxygen saturation (see above, figure 4.4). Thus, below 92% arterial blood gases should be measured to have a more precise measurement of oxygen (PaO2) and carbon dioxide (PaCO2) in the arterial blood.
