Common adverse reactions and prevention methods 1. Severe gastrointestinal distention is mainly caused by high airway pressure (>25cmH2O may exceed the pressure of the esophageal cardia) or open-mouth breathing and repeated gagging. For those with obvious gastrointestinal distension, the following measures can be considered: avoid carbonated beverage intake, avoid inspiratory positive pressure (IPAP) >25cmH2O, place a gastric tube for continuous drainage, and apply NPPV intermittently. 2. Misaspiration Misaspiration of oropharyngeal secretions or vomit can cause serious consequences such as pulmonary infection and aggravation of respiratory failure. Attention should be paid to the patient’s body position and prevention of gastrointestinal distention. 3, dryness of the mouth, nose and throat Most often seen when using the nasal mask and there is air leakage through the mouth, especially obvious in the cold season. Avoiding air leakage (which can significantly reduce the air flow through the oropharynx) and drinking water intermittently can usually relieve the symptoms, and a heated humidifier can also be used. However, due to water vapor condensation, more water can be deposited in the mask and tubing; some patients also complain of stuffiness and discomfort. Therefore, it should be chosen according to the specific situation of each patient. 4. Mask compression and nasal skin injury Mild mask compression is common.57 Reasonable adjustment of the mask position and the use of a silicone or air-cushioned mask suitable for the patient’s face, as well as adjustment of the tension of the fixation belt (the lowest tension that can avoid air leakage) can reduce the symptoms of mask compression. Skin damage to the nasal bridge is relatively rare and is mainly caused by prolonged compression. Intermittent release of the mask or rotation of different types of masks to avoid prolonged compression in the same position can avoid this complication. In addition, our self-developed silicone mask-type mask has good anti-air leakage and is more suitable for the national face type55,58. 5. Disorders of sputum evacuation NPPV is prone to thick sputum making sputum evacuation difficult, which is often related to the patient’s large ventilation demand or accompanied by large air leakage, making the total ventilation volume too large and unable to be fully wetted. Sufficient fluid volume should be ensured, small amounts of water should be drunk several times, a more functional active humidifier should be applied, and the patient should be allowed to actively cough intermittently (by temporarily disconnecting the ventilator from the mask) to ensure smooth sputum drainage. In addition, chest physiotherapy can be performed to assist the patient in sputum drainage. nppv should not interfere with the patient’s normal drinking, coughing, eating, etc. 6. fear (claustrophobia) Some patients have a fear of wearing a mask, especially an oronasal mask, which leads to nervousness or non-acceptance of NPPV treatment. Appropriate education and explanation can usually reduce or eliminate the fear. Observation of other patients successfully applying NPPV treatment is helpful to improve patients’ confidence and acceptability. 7. Pneumatic pressure injury Patients with combined pulmonary maculopathy should be alerted. The goal is to maintain basic ventilation, and airway pressure should not be raised in excessive pursuit of improvement in ventilation status.