What is capnography primarily used to measure?

Capnography is primarily used to measure the concentration of carbon dioxide in expired air, making it an essential tool in monitoring a patient's ventilatory status. This method involves assessing the levels of CO2 at the end of expiration, providing important insights into a person's respiratory function.

By analyzing the concentration of carbon dioxide, healthcare providers can gauge the effectiveness of ventilation, detect hypoventilation or hyperventilation, and monitor critical conditions such as respiratory distress or cardiac arrest. The waveform produced by capnography also offers additional diagnostic information such as identifying airway obstructions or evaluating the effectiveness of resuscitation efforts.

The other options—oxygen saturation, heart rate, and respiratory rate—are all important parameters in assessing a patient's overall health but are measured using different devices and methods, such as pulse oximetry for oxygen saturation, ECG for heart rate, and direct observation or a respiratory monitor for respiratory rate. Thus, the focus of capnography specifically on carbon dioxide levels sets it apart from these other vital signs.