In children, what is the compensatory mechanism available to maintain perfusion during injury?

• A. Increasing heart rate
• B. Increasing stroke volume
• C. Vasoconstriction of all arteries
• D. Respiratory rate increases

Answer: (A)

In children, the first way to preserve tissue perfusion during injury is by increasing heart rate. When blood loss lowers preload, stroke volume cannot rise enough to keep cardiac output, so the body speeds up the heart to maintain flow to vital organs (CO = heart rate × stroke volume). This tachycardia is a primary compensatory mechanism in pediatric patients.

Vasoconstriction does occur to shunt blood to essential organs, but it isn’t a uniform “vasoconstriction of all arteries” and isn’t the main kept-perfusion driver described here. An increased respiratory rate is a response to metabolic and ventilatory changes, not the direct mechanism to sustain perfusion in this scenario.