What does capnography measure during CPR?

• A. Heart rate
• B. Oxygen saturation
• C. Concentration of carbon dioxide in exhaled air
• D. Respiratory rate

Answer: (C)

Capnography measures the concentration of carbon dioxide in exhaled air, which is a critical indicator of a patient's ventilatory status during CPR. This measurement is particularly important because it provides real-time feedback on the effectiveness of chest compressions and ventilation. When CPR is being performed, adequate circulation and ventilation will allow carbon dioxide to be expelled from the body, which is reflected in the capnography readings.

An increase in the end-tidal carbon dioxide (ETCO2) levels during CPR usually indicates improved cardiac output and, hence, better perfusion to the lungs and other organs. Monitoring capnography can also help to identify when to reassess the patient and may provide a clue about the likelihood of return of spontaneous circulation (ROSC). In contrast, the other options focus on different parameters that do not directly reflect the effectiveness of CPR in terms of ventilation and perfusion.