What is the normal oxygen saturation of the Left Atrium?

What is the normal oxygen saturation of the Left Atrium?

• A. 95-99%
• B. 72-75%
• C. 85-89%
• D. 90-92%

Answer: (A)

Oxygen-saturated blood in the left atrium comes from the lungs, so its saturation mirrors arterial oxygen saturation. In healthy individuals, arterial O2 saturation is about 95-99% (often 95-100%), meaning the left atrium should also be around that level. Values like 72-75% reflect mixed venous blood returning to the right heart, not the left atrium, and lower ranges such as 85-89% or 90-92% would indicate hypoxemia or an atypical situation. So the normal left atrial oxygen saturation is roughly 95-99%.

Oxygen-saturated blood in the left atrium comes from the lungs, so its saturation mirrors arterial oxygen saturation. In healthy individuals, arterial O2 saturation is about 95-99% (often 95-100%), meaning the left atrium should also be around that level. Values like 72-75% reflect mixed venous blood returning to the right heart, not the left atrium, and lower ranges such as 85-89% or 90-92% would indicate hypoxemia or an atypical situation. So the normal left atrial oxygen saturation is roughly 95-99%.