Non-invasive ventilator is mainly a device for ventilating via nasal mask or face mask. Because there is no need to give patients tracheal intubation or tracheotomy, it is easy to operate, easily accepted by patients, and has few complications such as airway injury and ventilator-associated pneumonia, it is not only widely used for the treatment of inpatients with acute or chronic respiratory failure, but its home application is also increasing for outpatients with relatively stable conditions. Conditions requiring home treatment with noninvasive ventilators include obstructive sleep apnea hypoventilation syndrome, chronic heart failure, obesity hypoventilation syndrome, severe stable COPD respiratory failure, motor neuron disease and spinal thoracic deformity. How to properly select the appropriate noninvasive ventilator and ventilation mode to ensure therapeutic efficacy and safety has been an issue of concern for clinicians and patients. This article discusses the types and indications of commonly used noninvasive ventilators for introduction and analysis, in order to be helpful for clinical work. Although the therapeutic effects of different types of NIVs overlap to some extent (i.e., sometimes the same type of ventilator may be used for patients with different diseases and vice versa), the requirements for selecting the type of NIV are different for each disease based on the mechanism of occurrence and the purpose of treatment. The type and severity of the disease is an important basis for the selection of different types of ventilators and thus for their efficacy and safety. The following is a discussion of the application of different types of non-invasive ventilators, starting with the treatment of sleep apnea. This is for the reference of patients and their families. If you have questions about the selection of non-invasive ventilators, the use of the process of questions or difficulties, and need the help of doctors, you can come to my clinic, I will do my best to answer questions and provide technical support. 1.Continuous positive airway pressure ventilator Continuous positive airway pressure is by far the most common mode of ventilation for the treatment of sleep disordered breathing disorders, using a constant pressure to maintain the airway open during breathing, divided into two types of fixed pressure (Fixed-) and automatic pressure regulation (Auto-). It is usually used and can effectively relieve patients from daytime drowsiness and reduce the risk of cardiovascular disease. Patients with other diseases such as overlap syndrome (with both COPD and both diseases), OHS and chronic heart failure-related respiratory breathing disorders can also benefit from them due to their corrective and other effects. Treatment of Fixed- requires pressure titration under polysomnographic monitoring in a sleep laboratory. The goal of the titration is to determine an optimal pressure to eliminate or reduce apnea, hypoventilation, snoring, and arousals associated with respiratory effort, with criteria for judging the quality of the titration. The optimal pressure determined by titration is used as the basis for pressure setting in home ventilators.Fixed- Non-invasive respiration is effective and inexpensive, and is the most common type used for treatment today. Auto – is a device that works by automatic pressure titration. It automatically senses the degree of airway obstruction and its variability, automatically adjusts the pressure to open the airway and restore voluntary breathing. Thus, Auto- overcomes to some extent the shortcomings of Fixed- and reduces the need for manual pressure titration. Nevertheless, several studies have shown that it is not much better for efficacy compared to conventional fixation and is more expensive. Auto- is not currently recommended by the American Sleep Association for routine diagnostic and therapeutic use, nor is it recommended for the treatment of other non-obstructive sleep disorders caused by cardiopulmonary vascular disease or other causes of nocturnal hypoxemia. 2, compared with the bi-level positive airway pressure ventilation ventilator, the use of a wider range, not only for the treatment of various types of sleep breathing disorders, but also for many types of chronic ventilation insufficiency, especially with alveolar hypoventilation (i.e., there is an increase in blood carbon dioxide during the day) and other sleep breathing disorders or chronic respiratory diseases. There are two modes: without standby controlled ventilation frequency (-S) and with standby controlled ventilation frequency (-S/T). The difference between IPAP and EPAP is essential to maintain effective ventilation and reduce blood carbon dioxide, while the standby control ventilation frequency is extremely important for the treatment of increased blood carbon dioxide, i.e., during the day. There is no data to demonstrate patient efficacy or patient compliance superior to that for, and guidelines recommend its use for patients who require higher pressure levels of treatment or who cannot tolerate it. It is also used more frequently in clinical practice in patients with chronic heart failure with restrictive ventilation dysfunction due to contour pleural disease, severe stable COPD, obesity hypoventilation syndrome with residual alveolar hypoventilation (i.e., increased blood carbon dioxide during the day) despite treatment, and combined central sleep apnea syndrome and/or Chen-Schiff’s respiration. The ventilator with -S/T mode should be used for patients with unstable respiratory center, combined with central sleep apnea or Chen-Schiff’s respiration to ensure the efficacy and safety. 3.Adaptive servo-ventilator ventilator Ventilator is mainly used for the treatment of heart failure and central apnea syndrome and (or) Chen-Schiller’s respiration. It can also be used to treat complex sleep apnea syndrome and mixed sleep apnea syndrome. An EPAP is usually set enough to overcome obstructive sleep apnea, and then it automatically adjusts the support pressure per breath within a previously set range so that the ventilation reaches the patient’s recent average ventilation. The advantage of the EPAP is that it stabilizes breathing and avoids central apnea induced by respiratory alkalosis due to high support pressure. 4. average volume assured pressure support ventilation (AVAPS) ventilator The AVAPS ventilator is mainly used in patients with chronic alveolar hypoventilation (i.e., with increased blood carbon dioxide during the day), such as obesity hypoventilation syndrome, neuromuscular disease and COPD. this mode is characterized by a preset target ventilation volume (meaning tidal volume) and its adjustment of pressure according to the preset tidal volume (usually 8 ml/kg standard body weight ) to adjust the pressure. The advantage is that when the patient’s inspiratory effort, airway resistance, lung or chest compliance changes, it can ensure that the tidal volume does not change, and when there is a deterioration of the disease such as acute exacerbation of COPD and progressive neuromuscular disease, the machine can adapt to the change of the disease and increase the support pressure in time to guarantee the ventilation volume, thus ensuring the efficacy. 5.On the need to cooperate with oxygen therapy Generally speaking, for simple, no hypoxia performance in the waking state during the day, there is no need to cooperate with oxygen therapy. If the hypoxia is caused, after waiting for ventilator treatment, the airway is open during sleep, sleep apnea is gone, and hypoxia will not occur. For patients with various types of sleep disorders and other chronic respiratory insufficiency, if there is hypoxia in the waking state (arterial partial pressure of oxygen less than 60 mmHg) or hypoxemia occurs at night during sleep (arterial partial pressure of oxygen less than 55 mmHg, or blood oxygen saturation less than, for more than 5 minutes), they should be equipped with oxygen production devices, and under the guidance of professionals, oxygen should be increased for patients through ventilator Treatment.