Why does blood pO₂ often remain normal during moderate anemia, despite reduced hemoglobin?

💡 Explanation

The blood pO₂ remains near normal because even with reduced hemoglobin, the oxygen extraction ratio increases significantly to meet metabolic demands. This means a larger proportion of the oxygen present is unloaded to the tissues. Therefore, despite the anemia, tissue oxygenation can be maintained, rather than capillary transit time automatically decreasing.

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