In a pediatric patient with hemorrhage, what is the primary compensatory response?

• A. Increase heart rate
• B. Increase systolic blood pressure
• C. Increase diastolic blood pressure
• D. Decrease respiratory rate

Answer: (A)

The main idea is that the body's first move to hemorrhage is to preserve cardiac output by increasing the heart rate. When blood volume drops, preload falls and stroke volume tends to decline; because cardiac output equals heart rate times stroke volume, the quickest way to keep perfusion up is to raise the heart rate. In children, the heart’s ability to boost stroke volume is limited, so tachycardia is the most reliable and early compensatory response. Blood pressure can stay normal early on due to vasoconstriction maintaining systemic vascular resistance, so a rise in systolic pressure isn’t the primary early change. Decreasing respiratory rate isn’t a compensatory mechanism; in fact, respiration typically speeds up to help afterload and gas exchange in shock. So the correct response is an increase in heart rate.