What is the term for an abnormally low level of oxygen in the blood?

The term for an abnormally low level of oxygen in the blood is hypoxia. This condition occurs when there is insufficient oxygen available to the tissues, which can lead to various physiological effects and can impair cellular functions. Hypoxia is characterized by low oxygen saturation in arterial blood and can result from numerous factors, including respiratory diseases, high altitudes, or inadequate oxygen delivery.

The other terms have distinct meanings. Hypercapnia refers to an elevated level of carbon dioxide in the blood, which can occur due to impaired ventilation. Apnea is the cessation of breathing, leading to a temporary lack of oxygen entering the lungs. Asphyxia encompasses a broader range of conditions that can lead to oxygen deprivation, including choking or drowning. Each of these conditions is important in respiratory care, but hypoxia specifically denotes low oxygen levels in the blood.