Which of the following is a sign of hypovolemia?

• A. Tachycardia
• B. Hypertension
• C. Edema
• D. Crackles on lung auscultation

Answer: (A)

When blood volume drops, the body compensates by increasing heart rate to maintain cardiac output and keep blood pressure up. That rising pulse is a hallmark sign of hypovolemia because the heart is trying to push the reduced volume through the circulatory system. Hypertension would not occur with volume loss; edema suggests fluid overload or venous backing, not dehydration; crackles on lung auscultation indicate fluid in the lungs from overload or heart failure, not a low-volume state. So tachycardia best signals hypovolemia.