A previously healthy 70-kg man suffers an estimated blood loss of 1 liter. Which statements apply?

• A. His pulse pressure will narrow
• B. He will be tachycardic
• C. Both statements are true
• D. Pulse pressure will widen

Answer: (C)

When a healthy adult loses a significant amount of blood, the body activates compensatory mechanisms to preserve perfusion. Losing about one liter in a 70-kg person is roughly 20% of total blood volume, so the cardiovascular system responds with sympathetic stimulation that increases heart rate (tachycardia) and causes vasoconstriction to maintain mean arterial pressure.

This response lowers the effective preload, which tends to reduce systolic blood pressure. At the same time, peripheral vasoconstriction can keep or raise diastolic pressure. The result is a smaller difference between systolic and diastolic pressures—that is, a narrowed pulse pressure. Therefore, tachycardia is expected and the pulse pressure narrows.

Widening pulse pressure would be more typical of events with increased stroke volume or reduced arterial tone, not early acute hemorrhage. So the correct interpretation is that both tachycardia and pulse pressure narrowing occur.