Fluid volume deficit (FVD) can be indicated by which of the following symptoms?

Dry mucous membranes are a classic indicator of fluid volume deficit (FVD). When the body lacks adequate fluids, one of the first areas to exhibit signs of dehydration is the mucous membranes of the mouth and throat. These membranes rely on a certain level of hydration to maintain moisture, and when FVD occurs, they become dry and less effective in their function. This symptom is easily observable and can indicate that the body is in need of fluids, as hydration levels directly affect the mucous membranes' condition.

In contrast, increased urine output typically suggests that the body is adequately hydrated or even overhydrated, making it uncharacteristic for FVD. Fever and chills may point more towards an infectious process rather than FVD specifically, as these symptoms are not primarily related to fluid levels but rather immune responses. A throbbing headache can occur for various reasons, including dehydration, but it is not a direct indicator of FVD on its own, without the accompanying symptoms that more conclusively point to a lack of fluid. Thus, dry mucous membranes serve as a clear and direct symptom of fluid volume deficit.