In clinical use of a non-invasive ventilator, a mask is placed over the patient’s face. The mask is a nasal mask that covers the nose and an oronasal mask that covers the mouth and nose. A tube in the mask is connected to the ventilator to give pressure when the patient inhales to help the patient breathe. When the patient has difficulty in breathing, he or she is prone to respiratory fatigue. In this case, a non-invasive ventilator can be used to help the patient breathe through the non-invasive ventilator to relieve respiratory muscle fatigue, reduce respiratory muscle oxygen consumption, and relieve the patient’s symptoms of respiratory distress.