Summary Modes of mechanical ventilation.

Modes of mechanical ventilation

Controlled mechanical ventilation (CMV)
Delivers a preset number of breaths to the patient at a preset tidal
volume, pressure and flow rate. The ventilator performs all the work of
breathing – the patient cannot trigger the machine or breathe
spontaneously. Patients on CMV are sedated and paralysed.


Assist/control ventilation (ACV)
Spontaneously breathing patients trigger a breath and the ventilator
delivers gas at a preset tidal volume or preset pressure. The ventilator
will initiate a breath automatically should the patient fail to trigger
within a preset time.


Intermittent mandatory ventilation (IMV)
Delivers a preset number of breaths at a preset tidal volume and flow
rate but allows the patient to take spontaneous breaths between
machine-delivered breaths.


Synchronized intermittent mandatory ventilation
(SIMV)

Synchronizes breaths from the ventilator with the patient’s spontaneous
breaths. If the patient fails to take a spontaneous breath within a set
time the ventilator delivers a mandatory breath at either a preset tidal
volume (SIMV/volume cycled) or preset inspiratory pressure
(SIMV/pressure cycled).