Which monitoring method is used to verify proper airway placement and monitor ventilation during post-cardiac arrest care?

• A. End-tidal CO2 monitoring (capnography)
• B. Pulse oximetry
• C. ECG
• D. Blood gas

Answer: (A)

End-tidal CO2 monitoring, or capnography, is used because it provides real-time confirmation that a tracheal tube is in the airway and not in the esophagus. A proper airway placement yields a characteristic CO2 waveform and measurable end-tidal CO2 with each breath, while esophageal intubation often produces little to no CO2. Beyond placement, capnography continuously tracks ventilation by showing changes in the amount of CO2 being exhaled, which reflects how well the patient is ventilated and how perfusion and metabolism are interacting. In the post-cardiac arrest setting, a rise in end-tidal CO2 can signal return of spontaneous circulation, giving a rapid, noninvasive cue about perfusion status. While pulse oximetry and ECG provide information about oxygenation and heart rhythm, they do not verify airway placement or offer the same ongoing ventilation feedback. Blood gas can measure CO2 but is invasive and not continuous, limiting its usefulness for immediate airway verification and dynamic ventilation monitoring.