Concept: OSAS is defined as at least 30 episodes of apnea during a 7-hour nocturnal sleep period in adults, each episode of which is characterized by a cessation of oral and nasal airflow for more than 10 seconds or an apnea index (i.e., the average number of apneas per hour) of greater than 5. Clinically, there is also central sleep apnea (CSA) and mixed sleep apnea (MSA). Etiology: 1, narrowing or blockage of the upper airway: nose and nasopharynx, oropharynx and soft palate, root of the tongue 2, obesity 3, endocrine disorders 4, tissue relaxation in old age Pathophysiology: 1, respiratory acidosis 2, heart failure 3, hypoxemia, hypercapnia Arrhythmia is the main cause of sudden death in sleep Symptoms: 1, headache in the morning, etc. 2, the nighttime symptoms of the heaviest, can not fall asleep quietly, dreaming, restlessness, open-mouth Breathing 3. High-pitched snoring during daytime sleep 4. Complicated cardiovascular diseases: hypertension, arrhythmia, cardiorespiratory failure, etc. Examination: 1. Polysomnography: continuous sleep observation and detection of OSAS patients throughout the night. Monitoring content: cardiac monitoring – cardiac function pulmonary function electrooculogram, electroencephalogram, electromyography (diaphragm, chin and tongue muscles, pharyngeal muscles, diastasis) oxygen saturation and so on. 2, routine otolaryngology examination, fiberoptic nasopharyngoscopy, imaging. Treatment: 1, Surgery (in principle, surgery should be performed to remove the cause of the disease): uvulopalatopharyngoplasty or palatopharyngoplasty. 2, severe OSAS patients, especially certain patients with poor cardiopulmonary function and low oxygen saturation, tracheotomy.