True or False: The SVC has a lower venous saturation than the IVC.

The statement that the superior vena cava (SVC) has a lower venous saturation than the inferior vena cava (IVC) is generally true because of the way blood is returned to the heart from different regions of the body.

Venous blood from the upper body drains into the SVC, while blood from the lower body and abdominal organs drains into the IVC. The SVC primarily collects blood that has already been utilized by the brain and upper limbs, which often reflects a lower oxygen saturation due to its proximity to tissues that consume oxygen. In contrast, the IVC gathers blood returning from the lower body, which tends to have a relatively higher oxygen saturation because it has not yet passed through the metabolically active areas of the body to the same extent as the blood from the upper body.

This physiological difference helps to explain why the SVC can show lower oxygen saturation values compared to the IVC under normal circumstances. The options suggesting variations based on physical activity (exercise) or patient age (older patients) don’t significantly alter the fundamental hemodynamics governing the saturation differences between these two vessels.