There are numerous ways to evaluate a patient’s oxygen. Pulse oximetry or saturation (SpO2) is one of them. Oxygen saturation is the fraction of oxygen-saturated hemoglobin relative to total hemoglobin in the blood. A normal blood oxygen saturation level in a patient without chronic lung disease is between 95 to 100%. A confirmatory test for an abnormal oxygen saturation often is an arterial blood gas (ABG) in which this number of arterial gasses including oxygen are measured directly by sampling arterial blood from the patient. Oxygen saturations below 88% in a patient deprives tissues of oxygen which commonly leads to tissue injury. Providing supplemental oxygen to maintain the saturation above 88% is the standard of care to adequately oxygenate body tissue and to prevent tissue injury.
Hypoxemia and Oxygen Saturations