Osmosis video - Respiratory: Pulse oximetry

Pulse oximetry is a non-invasive, easy way to measure the amount of arterial oxygenation, or Sa02. It uses a small device, called a pulse oximeter, which is placed on a finger, toe, or earlobe. The device shines a light through the skin and measures the amount of oxygen in the blood by measuring the absorption of the light by hemoglobin, the protein in the blood that carries oxygen. For most people, a normal value of SpO2 is 95% or greater, while low values may indicate pulmonary or other oxygenation problems. Inaccurate readings can be due to poor blood flow to the extremities, motion artifacts, nail polish, or exposure to light.