Which of the following symptoms is most indicative of dehydration in an elderly client?

Dry mucous membranes are a primary indicator of dehydration, particularly in elderly clients. As the body loses fluids, the mucous membranes in the mouth and other areas can become less moist, leading to dryness. In older adults, this symptom can be particularly concerning, as they may not adequately perceive their thirst or may have altered responses to dehydration due to age-related physiological changes.

While increased appetite may be associated with other health conditions or compensatory mechanisms, it does not directly correlate with hydration status. Frequent urination can sometimes indicate fluid overload or certain medical conditions rather than dehydration itself. Elevated blood pressure is generally not a direct symptom of dehydration; in fact, dehydration can often lead to lowered blood pressure due to decreased blood volume. Thus, observing dry mucous membranes is a clear and significant indicator of dehydration, highlighting the importance of monitoring hydration status in elderly patients.