You searched for: “capnograph
capnograph (s) (noun), capnographs (pl)
1. An instrument by which a continuous graph of the carbon dioxide content of expired air is obtained.
2. A system for monitoring the concentration of exhaled carbon dioxide, consisting of a sensor placed in the breathing circuit or a tube that carries part of the exhaled gases to the analyzing device, a mass spectrometer or an infrared spectrometer, and devices to provide continuous visual (cathode ray tube) and graphic (printer) displays.