A control system ensures that the ventilator produces the correct breathing pattern.
 
This requires setting basic controls, including:
 
Size of the breath
How fast and often the breath is brought in and let out
How much effort, if any, the patient needs to exert to start a breath
 
A spontaneous breath occurs when the patient can control the timing and size of the breath. Otherwise, the effort involves a mandatory breath. A particular pattern of spontaneous and mandatory breaths is referred to as a ventilation mode.
 
Numerous ventilation modes allow ventilators to produce various breathing patterns, to suit the individual needs of the patient. These modes coordinate with ventilator functions.