During respiratory distress in pediatrics, the respiratory muscles account for up to what percentage of cardiac output?

• A. 20%
• B. 40%
• C. 60%
• D. 80%

Answer: (B)

During respiratory distress in children, the muscles used for breathing work much harder and need more oxygen and nutrients. To meet this demand, the heart redirects blood flow toward these respiratory muscles, so their share of the cardiac output rises substantially. It can approach forty percent, which is the upper end of what’s typically observed in pediatric distress. This high distribution to the respiratory muscles can reduce flow to other organs and contribute to hemodynamic instability if the distress continues. The other figures are less representative of the peak oxygen demand these muscles can reach during severe work of breathing.