What is the primary characteristic of stagnant hypoxia?

Stagnant hypoxia is primarily characterized by impaired blood flow, which directly affects the delivery of oxygen throughout the body. This condition occurs when there is adequate oxygen in the air and the body's ability to utilize it is intact, but the blood cannot effectively transport oxygen due to issues such as reduced cardiac output or vascular obstruction. As a result, although the oxygen content in the lungs and tissues may be normal, the reduced blood flow leads to insufficient oxygen delivery to tissues, causing hypoxia.

In contrast, the other options refer to different types or causes of hypoxia. Insufficient oxygen in the air relates to hypoxic hypoxia, while an inability to utilize oxygen is associated with cytotoxic hypoxia. Low blood oxygen saturation can occur in various forms of hypoxia, but it isn't the defining feature of stagnant hypoxia itself, which is specifically linked to blood flow problems. Thus, understanding stagnant hypoxia focuses on the blood flow impairment as the core issue affecting oxygen transport.