A nurse is assessing a client who reports nausea and vomiting for the past 24 hr. Which of the following findings should indicate to the nurse that the client is experiencing dehydration?

Choice A reason: Tachycardia is a classic sign of dehydration. When fluid volume decreases, cardiac output drops, and the body compensates by increasing heart rate to maintain perfusion. This makes tachycardia a reliable indicator of dehydration in a client with prolonged vomiting. Choice B reason: A urine output of 850 mL per day is within normal limits (normal adult urine output is 800–2000 mL/day). Dehydration would typically present with oliguria, defined as less than 400 mL/day. Therefore, this finding does not indicate dehydration. Choice C reason: A serum sodium level of 130 mEq/L indicates hyponatremia, which can occur with excessive vomiting and fluid loss. However, hyponatremia is not a direct indicator of dehydration; it reflects electrolyte imbalance. Dehydration is more directly identified by clinical signs such as tachycardia, hypotension, and dry mucous membranes. Choice D reason: Distended neck veins suggest fluid overload, not dehydration. In dehydration, neck veins are typically flat or collapsed due to reduced circulating volume. This finding is inconsistent with dehydration.