Ventilation is the movement of air into and out of the lungs, that is inhalation and exhalation. This is done either spontaneously, that is, through the automatic action of breathing, or mechanically, with the help of a ventilator. Using a ventilator, air enters your lungs-either non-invasively (via a mask worn over your mouth and/or nose) or invasively (via a tracheotomy). See also: Invasive ventilation; Non-invasive ventilation; Tracheotomy