Oxygen saturation (medicine)

Blood circulation: Red = oxygenated (arteries), Blue = deoxygenated (veins)

Oxygen saturation is the fraction of oxygen-saturated haemoglobin relative to total haemoglobin (unsaturated + saturated) in the blood. The human body requires and regulates a very precise and specific balance of oxygen in the blood. Normal arterial blood oxygen saturation levels in humans are 96–100 percent.[1] If the level is below 90 percent, it is considered low and called hypoxemia.[2] Arterial blood oxygen levels below 80 percent may compromise organ function, such as the brain and heart, and should be promptly addressed. Continued low oxygen levels may lead to respiratory or cardiac arrest. Oxygen therapy may be used to assist in raising blood oxygen levels. Oxygenation occurs when oxygen molecules (O
2
) enter the tissues of the body. For example, blood is oxygenated in the lungs, where oxygen molecules travel from the air and into the blood. Oxygenation is commonly used to refer to medical oxygen saturation.

  1. ^ Kobayashi, M; Fukuda, S; Takano, KI; Kamizono, J; Ichikawa, K (June 2018). "Can a pulse oxygen saturation of 95% to 96% help predict further vital sign destabilization in school-aged children?: A retrospective observational study". Medicine. 97 (25): e11135. doi:10.1097/MD.0000000000011135. PMC 6023980. PMID 29924014. S2CID 49312513.
  2. ^ "Hypoxemia (low blood oxygen)". Mayo Clinic. mayoclinic.com. Retrieved 6 June 2013.