What is the normal oxygen saturation range for the Pulmonary Artery (PA)?

• A. 68-70%
• B. 72-75%
• C. 75-78%
• D. 70-72%

Answer: (B)

Think of the oxygen saturation in the pulmonary artery as the mixed venous oxygen saturation—the amount of O2 remaining after the tissues have taken what they need. In a healthy adult at rest, this SvO2 sits in the mid-70s percent, with a typical range roughly from the mid-60s up to about 75%. Because of that, the range that best fits normal pulmonary-artery saturation is around 72–75%. The other options sit outside the usual window: values in the high 60s to around 70% are a bit low for normal venous blood, while values approaching the high 70s to 80% would be closer to arterial levels and not characteristic of mixed venous blood. This measurement comes from the distal pulmonary artery using a catheter and helps assess the balance between oxygen delivery and consumption across the body.