The causes of severe obstructive sleep apnea hypoventilation syndrome include abnormal upper airway anatomy, abnormal upper airway dilator muscle tone, and abnormal regulation function of the respiratory center. Common treatments include general treatment, continuous positive pressure ventilation treatment, mouthpiece treatment, surgical treatment and so on. 1. General treatment: obesity will not only lead to an increase in body fat, but also lead to the pharynx, nasal fat deposition, causing cavity narrowing, obese people need to actively lose weight, weight loss can be effective in alleviating the symptoms; long-term alcohol consumption, lying on the back will be due to muscle relaxation, tissue collapse and aggravate the symptoms of sleep hypoventilation, you need to take to give up alcohol, the establishment of the side sleep habits. 2. Continuous positive pressure ventilation therapy: the machine wearing a belt breathing and treatment, one of the more widely used and effective methods. The principle is to ensure that patients with severe obstructive sleep hypoventilation syndrome can breathe well during sleep through mechanical ventilation at a certain pressure. 3. Oral appliance therapy: Wearing a specific intraoral appliance during sleep, stretching the lower jaw forward to move the tongue root forward and expand the airway behind the tongue root. 4. Surgical treatment: it is one of the important means of treating severe obstructive sleep apnea hypoventilation syndrome. The prediction of surgical efficacy and the prevention of serious surgical complications are important factors in the success or failure of surgery. Such as children adenoidectomy, tonsillectomy, uvula palatopharyngoplasty. Mandibular advancement surgery, etc. Patients with severe obstructive sleep apnea hypoventilation syndrome are recommended to visit the hospital for sleep apnea monitoring and targeted treatment after clarifying the etiology.