Capnography during pediatric CPR provides information most closely related to which physiologic parameter?

• A. Lung volume
• B. Systemic arterial pressure
• C. Oxygen saturation
• D. Perfusion quality

Answer: (D)

Capnography during pediatric CPR mainly tells you about perfusion quality. The end-tidal CO2 level reflects how much CO2 is being delivered to the lungs by the circulating blood, which depends on cardiac output and the effectiveness of chest compressions. If compressions are producing good blood flow, more CO2 reaches the lungs and ETCO2 rises; if perfusion is poor, ETCO2 stays low. This is why ETCO2 is used as a surrogate for how well perfusion is being maintained and for signaling potential ROSC when levels jump. It isn’t a direct measure of lung volume, arterial pressure, or oxygen saturation, which are tracked by other monitors.