What does a capnogram display?

A capnogram is a graphical representation that specifically displays the levels of carbon dioxide (CO2) in a patient's exhaled air over time. The output is typically shown as both a waveform and a numeric value, making it easy for healthcare providers to monitor the patient's ventilation status. The waveform provides a visual representation of the breathing cycle, highlighting phases such as the inhalation and exhalation of CO2-rich air, as well as the baseline CO2 levels during inhalation. This is critical for assessing respiratory function and detecting issues such as hypoventilation or hyperventilation.

The other options provided do not accurately describe what a capnogram measures. For example, while oxygen levels during inhalation are important for assessing respiratory function, they are not depicted in a capnogram. Similarly, heart rate and blood pressure are vital signs but are not related to carbon dioxide monitoring. Lastly, the volume of air exchanged is related to lung function and ventilation, but it is measured separately and not presented in a capnogram format. Therefore, the choice of CO2 levels as a waveform and numeric display distinctly identifies the function of a capnogram.