Ventilators are classified according to the switching mode o
(1) constant pressure type: after the pressure in the respiratory tract reaches the expected value, the ventilator opens the expiratory valve, and the chest and lungs passively collapse or exhale by negative pressure. When the pressure in the airway continues to drop, the ventilator produces airflow again through positive pressure and causes inhalation.
(2) constant volume type: the expected tidal volume is sent into the lungs by positive pressure, and after reaching the expected tidal volume, the air supply is stopped and the expiratory state is entered.
(3) timing: inhale and exhale according to the pre-designed inspiratory and expiratory time.
(4) mixed type (multi-functional type).