Basic and Clinical Sciences Examination (BCSE) Practice Exam 2026 – Comprehensive All-in-One Guide for Exam Success

In stagnant hypoxia, the primary issue is that there is a reduced blood flow to tissues, which limits the delivery of oxygen despite potentially normal levels of oxygen in the blood. As a result, the consumption of oxygen by the tissues exceeds the delivery due to impaired circulation.

This situation leads to a decreased PvO2, which represents the partial pressure of oxygen in the venous blood returning to the heart. The reduced transit of blood through the capillaries contributes to inadequate oxygen being picked up by the blood, resulting in lower levels of oxygen in the venous circulation. Therefore, in stagnant hypoxia, where the oxygen delivery is compromised due to stasis in blood flow, the levels of PvO2 decrease, which aligns accurately with the physiological understanding of how blood oxygen levels respond under conditions of impaired perfusion.