Which monitoring modality is essential to assess ventilation during procedural sedation?

• A. Pulse oximetry
• B. Capnography is essential to assess ventilation during procedural sedation.
• C. Electroencephalography
• D. Temperature monitoring

Answer: (B)

Capnography, or continuous end-tidal CO2 monitoring, is essential because it gives real-time information about ventilation, not just oxygenation. During procedural sedation, sedatives can blunt respiratory drive and cause airway obstruction or hypoventilation long before oxygen levels drop. The capnography tracing shows the amount of CO2 being expired and the pattern of breathing; a loss or alteration of the waveform, rising CO2, or sudden apnea alerts you to ventilation problems immediately, allowing prompt intervention to protect the airway and prevent hypoxemia.

Pulse oximetry, while important for sensing oxygenation, can remain normal for a while even when ventilation is impaired, especially if the patient is on supplemental oxygen. EEG and temperature monitoring don’t provide direct information about ventilation, so they’re not used to assess how well a patient is ventilating during sedation.