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:

1. The sensor is a non-disposable device that takes continuous carbon dioxide measurements from a patient’s exhaled breath. This is attached to the right side of the VIVO 55 ventilator, and allows real-time adjustment of ventilator settings while the patient is being ventilated
2. A disposable airway adapter that attaches to the patient’s circuit

Once the end-tidal CO₂ monitor is assembled and connected to the right side of the VIVO 55 ventilator, it should be calibrated before use. To do this:

1. Turn on the ventilator using the switch on the right side of the device
2. To access the calibration programme in the menu, select the ‘others’ menu, and locate the ‘FiO₂/ CO₂ calibration’ option
3. Follow the on-screen instructions to ‘start CO₂ zeroing’

Once the end-tidal CO₂ monitor has been zeroed, the machine will give an end-tidal CO₂ reading when the ventilator is running.