During CPR, how can capnography help assess quality of chest compressions?

During CPR, how can capnography help assess quality of chest compressions?

• A. ETCO2 values correlate with cardiac output; rising values suggest improved perfusion during compressions.
• B. ETCO2 directly measures arterial blood pressure.
• C. Capnography is not useful during CPR.
• D. ETCO2 only reflects oxygenation.

Answer: (A)

During CPR, end-tidal CO2 shows how well blood is moving through the lungs, which reflects the amount of blood being circulated by chest compressions. CO2 is carried in venous blood from tissues to the lungs; when compressions push more blood forward, more CO2 is delivered to the lungs and exhaled, so the ETCO2 rises. Therefore, rising ETCO2 values indicate improved perfusion and better cardiac output from the compressions. If perfusion improves further or ROSC occurs, ETCO2 can rise even more or spike suddenly. ETCO2 is not a direct measure of arterial blood pressure, so it doesn’t directly tell you blood pressure. Capnography is indeed useful during CPR for monitoring perfusion and spotting ROSC. ETCO2 does not reflect oxygenation alone; it reflects the interplay of ventilation and especially perfusion during CPR, serving as a surrogate for how effectively the chest compressions are delivering blood to the lungs.

During CPR, end-tidal CO2 shows how well blood is moving through the lungs, which reflects the amount of blood being circulated by chest compressions. CO2 is carried in venous blood from tissues to the lungs; when compressions push more blood forward, more CO2 is delivered to the lungs and exhaled, so the ETCO2 rises. Therefore, rising ETCO2 values indicate improved perfusion and better cardiac output from the compressions. If perfusion improves further or ROSC occurs, ETCO2 can rise even more or spike suddenly.

ETCO2 is not a direct measure of arterial blood pressure, so it doesn’t directly tell you blood pressure. Capnography is indeed useful during CPR for monitoring perfusion and spotting ROSC. ETCO2 does not reflect oxygenation alone; it reflects the interplay of ventilation and especially perfusion during CPR, serving as a surrogate for how effectively the chest compressions are delivering blood to the lungs.