Capnography primarily provides information about which physiological parameter?

Capnography primarily provides information about which physiological parameter?

• A. CO2 in exhaled air
• B. Blood glucose
• C. Blood pressure
• D. Oxygen saturation

Answer: (A)

Capnography measures the amount of carbon dioxide in exhaled breath over time, focusing on the end-tidal CO2 that appears at the end of expiration. This directly reflects ventilation and alveolar CO2 elimination, so the waveform and EtCO2 value tell you how effectively a patient is ventilating. It’s particularly useful for detecting hypoventilation, apnea, airway obstruction, or disconnection in real time during sedation or anesthesia. While PaCO2 in blood is related, capnography provides a noninvasive estimate of ventilation through the CO2 in exhaled air, not measurements of glucose, blood pressure, or oxygen saturation, which are monitored by other methods.

Capnography measures the amount of carbon dioxide in exhaled breath over time, focusing on the end-tidal CO2 that appears at the end of expiration. This directly reflects ventilation and alveolar CO2 elimination, so the waveform and EtCO2 value tell you how effectively a patient is ventilating. It’s particularly useful for detecting hypoventilation, apnea, airway obstruction, or disconnection in real time during sedation or anesthesia. While PaCO2 in blood is related, capnography provides a noninvasive estimate of ventilation through the CO2 in exhaled air, not measurements of glucose, blood pressure, or oxygen saturation, which are monitored by other methods.