In volume depletion, mentation can be which of the following?

• A. BAR/QAR
• B. Obtunded
• C. Normal
• D. Hyperactive

Answer: (B)

Volume depletion lowers the circulating blood volume, which can reduce cerebral perfusion. When the brain isn’t receiving enough blood, alertness and responsiveness can decline, leading to an obtunded state—where the person is less responsive and slower to react but not unconscious. In milder dehydration, mentation may still be normal, but as hypovolemia becomes clinically significant, obtunded becomes a more likely finding. Hyperactive mentation is not typical of uncomplicated volume depletion, and BAR/QAR or normal mentation would only be expected if perfusion is preserved or the dehydration is very mild.