End-tidal CO₂ is the level of carbon dioxide that is released at the end of an exhaled breath. The End-tidal CO₂ monitor consists of two main components:

• The Capnostat sensor is a non-disposable device that takes continuous carbon dioxide measurements from a patient’s exhaled breath. This is attached via a USB port into the side of the ventilator, and allows real-time adjustment of ventilator settings while the patient is being ventilated
• An adapter that attaches to the patient’s circuit. This is disposable