Obstructive sleep apnea hypoventilation syndrome is defined as an apnea-hypoventilation index (the total number of apneas and hypoventilations occurring per hour of sleep) ≥ 5, along with symptoms of excessive daytime sleepiness. the prevalence of men meeting the above definition is about 4% and women about 2% in the population aged 30-60 years. Risk factors for sleep apnea include obesity, increased neck circumference, craniofacial anomalies, hypothyroidism, and acromegaly. Disorders to be differentiated include simple snoring, central sleep apnea and other disorders that cause daytime sleepiness (e.g., sleep deprivation, abnormal physiological rhythms, episodic sleeping sickness and periodic limb movements). Polysomnography is the standard test for diagnosing sleep apnea, but the test is highly specialized and time-consuming. Portable monitoring allows the number of episodes of dyspnea per hour to be recorded, which is used to calculate a dyspnea index. Studies have shown that sleep apnea is a risk factor for cardiovascular disease and that there is a causal relationship between it and hypertension. Polysomnography is the recommended method for examining patients with suspected sleep disorders, including sleep apnea. It records sleep by EEG, oculomotor and electromyography and stages sleep. Sleep apnea and hypoventilation are defined as a marked decrease in airflow or tidal volume, often accompanied by a decrease in oxygen saturation, and a return to normal as the patient awakens. The patient’s breathing, limb movements and blood pressure are also monitored. Treatment 1.Continuous positive airway pressure therapy: Continuous positive airway pressure therapy can rapidly relieve apnea and hypoventilation, which can relieve drowsiness and improve the patient’s quality of life. 2.Conservative treatment and weight loss: Conservative treatment includes sleeping on the side, avoiding alcohol, avoiding sedatives and losing weight. All obese patients with sleep apnea should lose weight. Weight loss as basic treatment is indicated for mild to moderate patients, especially those who are not interested in other treatment measures. 3. Mandibular advancement: Many types of mouthpieces have been designed to treat sleep apnea. Most of these mouthpieces are fixed to the teeth to shift the lower jaw and serve to correct the posterior mandibular and posterior lingual cavity. For patients with mild to moderate sleep apnea, mandibular advancement is feasible, but not the most ideal option. 4.Surgery: Surgery for sleep apnea includes uvulopalatopharyngoplasty, laser-assisted uvulopalatopharyngoplasty, tonsil removal, partial tongue removal or ablation, mandibular or maxillary reconstruction, and tracheotomy.