What does capnography measure non-invasively?

Capnography measures end-tidal carbon dioxide (CO2) levels non-invasively, which is a crucial aspect of assessing a patient's respiratory status. This measurement reflects the concentration of carbon dioxide in exhaled air, providing insights into the patient’s ventilation and overall metabolic activity.

Monitoring end-tidal CO2 is particularly valuable in various clinical situations, including during sedation, mechanical ventilation, and in patients presenting with respiratory distress. It allows healthcare providers to assess how well carbon dioxide is being eliminated and if there are any issues with the patient's breathing or circulation.

The other options, while important in their own right, do not pertain to what capnography measures. Heart rate variability relates to the heart's rhythm and autonomic nervous system function, body temperature monitors thermal status, and blood oxygen saturation indicates how well oxygen is being carried in the blood. None of these are assessed through capnography, which is specifically focused on carbon dioxide levels.