Sleep apnea hypopnea syndrome is a clinical syndrome in which apnea and/or hypoventilation, hypercapnia, and sleep disruption occur repeatedly during sleep due to various reasons, resulting in a series of pathophysiologic changes in the body. Definition and classification: (1) Definition: Sleep apnea and hypoventilation syndrome refers to the clinical symptoms such as repeated episodes of apnea more than 30 times per night during sleep or sleep apnea hypoventilation index (AHI) = 5 times/hour and accompanied by drowsiness. Apnea refers to the complete cessation of nasal and oral respiratory airflow for more than 10 seconds during sleep; hypoventilation refers to the reduction of respiratory airflow intensity (amplitude) by more than 50% compared with the basal level during sleep, accompanied by a decrease in oxygen saturation by ¡±4% compared with the basal level or micro-arousal; AHI refers to the number of apneas plus hypoventilations per hour of sleep time. (ii) Classification: 1. Central type (CSAS) 2. Obstructive type (OSAS) 3. Mixed type (MSAS) Epidemiology: Take OSAHS as an example, in the population over 40 years old, the prevalence rate in the United States is 2%-4%, with more males than females, and a higher prevalence rate in the elderly, Australia is as high as 6.5%, China’s Hong Kong region is 4.1%, Shanghai city is 3.62%, Changchun city is 4.81 Australia up to 6.5%, Hong Kong 4.1%, Shanghai 3.62%, Changchun 4.81%. Etiology and pathogenesis: (a) central type of respiratory sleep apnea syndrome (CSAS) CSAS alone is rare, usually no more than 10% of patients with apnea, and only 4% have been reported. Patency can be further categorized into two main groups: hypercapnia and normocapnia. It can coexist with obstructive sleep apnea ventilation syndrome and most have neurologic or motor system pathology. The pathogenesis may be related to the following factors: 1) reduced responsiveness of the respiratory center to different stimuli during sleep; 2) instability of the central nervous system to respiratory feedback regulation caused by hypoxemia, especially changes in CO2 concentration; 3) abnormalities in the mechanism of expiratory and inspiratory transition, etc. (ii) Obstructive sleep apnea and hypoventilation syndrome (OSAHS) accounts for the majority of SAHS, with family aggregation and genetic factors, and most of them have the pathological basis of narrowing of the upper respiratory tract, especially in the nose and pharynx, such as obesity, allergic rhinitis, nasal polyp, enlarged tonsils, soft palate laxity, palatal droop over-length and over-thickness, enlarged tongue, tongue root backwardness, mandibular retraction, temporomandibular joint dysfunction, and small-jawed malformations. etc. Some endocrine diseases can also be combined with this disease. Its pathogenesis may be related to the increased collapse of soft tissues and muscles of the upper airway during sleep and the decreased responsiveness of the upper airway muscles to the stimulation of low oxygen and carbon dioxide during sleep, in addition, it is also related to the combined effect of the nerve, body fluids, endocrine factors, and so on. Clinical manifestations: (a) daytime clinical manifestations: 1, drowsiness: the most common symptom, the light performance of daytime work or study time sleepiness, drowsiness, serious when eating, talking to people can fall asleep, and even the occurrence of serious consequences, such as dozing off while driving, resulting in traffic accidents. 2.Dizziness and fatigue: Due to repeated apnea and hypoxemia at night, the sleep continuity is interrupted, the number of waking up increases, the quality of sleep decreases, and there are often mildly different dizziness, fatigue and fatigue. 3.Mental behavioral abnormalities: inattention, decline in fine manipulation ability, memory and judgment, inability to work when the symptoms are severe, the elderly can be manifested as dementia. The damage of nocturnal hypoxemia to the brain and the change of sleep structure, especially the decrease of deep sleep phase is the main reason. 4, headache: often in the early morning or at night, hidden pain is common, not intense, can last 1-2 hours, sometimes need to take painkillers to relieve, and with the elevation of blood pressure, intracranial pressure and changes in cerebral blood flow. 5, personality changes: irritability, agitation, anxiety, etc., family and social life are affected to a certain extent, due to the gradual emotional estrangement from family members and friends, depression may occur. 6, sexual dysfunction: about 10% of the patients can appear loss of libido, or even impotence. (II) Clinical manifestations at night: 1, snoring: it is the main symptom, the snoring is irregular, varying in height, often snoring – air flow stops – gasping – snoring alternately, generally the time of air flow interruption is 20-30 seconds, and the individual up to 2 minutes or more, at this time, the patient may appear obvious cyanosis. 2.Apnea: 75% of the sleepers in the same room or bed found that the patient had apnea, and they were often worried that the respiration could not be restored and woke up the patient, the apnea was more often terminated with wheezing, waking up with breath or loud snoring. osaheims patients had obvious thoracic and abdominal paradoxical respiration. 3.Holding awake: Suddenly holding awake after apnea, often accompanied by rolling over, involuntary movement of limbs or even twitching, or suddenly doing up, feeling panic, chest tightness or precordial discomfort. 4.Hyperactivity and restlessness: due to hypoxemia, patients roll over and turn more frequently at night. 5.Hyperhidrosis: sweating is more frequent, which is obvious in the neck and upper chest, and is related to hypercapnia caused by respiratory exertion and apnea after airway obstruction. 6.Nocturia: some patients complained of increased urination at night, and individual had enuresis. 7.Abnormal sleep behavior: manifested as fear, shrieking, murmuring, nocturnal wanderings, hallucinations, etc.. (C) the performance of systemic organ damage: OSAHS patients often with cardiovascular system abnormalities as the first signs and symptoms, can be hypertension, coronary heart disease independent risk factors. 1.Hypertension: the incidence of hypertension in OSAHS patients is 45%, and the therapeutic effect of antihypertensive drugs is not good. 2.Coronary heart disease: manifested as various types of arrhythmia, nocturnal angina and myocardial infarction. The twenty due to hypoxia caused by coronary artery endothelial damage, lipid deposition in the vascular endothelium, as well as increased erythrocytes increased blood viscosity. 3.Various types of arrhythmia. 4, pulmonary heart disease and respiratory failure 5, ischemic or hemorrhagic cerebrovascular disease 6, mental anomalies: such as manic psychosis or depression 7, diabetes mellitus (d) Signs: CSAS can have the corresponding signs of the original disease, OSAHS patients may have obesity, turbinate hypertrophy, etc.. Laboratory and other tests: (a) blood tests: long duration of the disease, hypoxemia is serious, blood red blood cell count and hemoglobin may have different degrees of increase. (ii) Arterial blood gas analysis: in severe disease or combined with pulmonary heart disease and respiratory failure, there may be hypoxemia, hypercapnia and respiratory acidosis. (C) Chest X-ray examination: when complicated by pulmonary hypertension, hypertension and coronary heart disease, there may be symptoms such as enlarged heart shadow and protruding pulmonary artery segment. (D) Lung function test: when the condition is serious with pulmonary heart disease and respiratory failure, there are different degrees of ventilation dysfunction. (e) Electrocardiogram: when there is hypertension, coronary heart disease, ventricular hypertrophy, myocardial ischemia or arrhythmia and other changes. Diagnosis: According to the typical clinical symptoms and signs, it is not difficult to diagnose SAHS. To confirm the diagnosis and to understand the severity and type of the condition, corresponding examinations are required. (I) Clinical diagnosis: According to the patient’s snoring with apnea during sleep, daytime sleepiness, obesity, thick neck circumference and other clinical symptoms, a preliminary clinical diagnosis can be made. (ii) Polysomnography: PSG monitoring is the gold standard for confirming the diagnosis of SAHS and can determine its type and severity. (iii) Etiological diagnosis: Routine ear, nose, throat and oral cavity examination is performed for confirmed SAHS to find out whether there are local anatomical and developmental abnormalities, hyperplasia and tumors. Cranial and cervical radiographs, CT and MRI to determine the cross-sectional area of the oropharynx can be used to determine the localization of stenosis. Measurement of the endocrine system can be performed in some patients. Differential diagnosis: (i) Simple snoring: there is obvious snoring, PSG examination is not consistent with the diagnosis of upper airway resistance syndrome, there is no apnea and hypoventilation, and there is no hypoxemia. (ii) Upper airway resistance syndrome: increased airway resistance. (iii) Episodic somnolence: excessive daytime sleepiness with sudden collapse during episodes. There is a family history. Treatment: (A) Treatment of central sleep apnea syndrome: 1. Treatment of primary disease: e.g. neurological disease, treatment of congestive heart failure. 2, respiratory excitation drugs: mainly to increase the driving force of the respiratory center, improve apnea and hypoxemia. Drugs: amitriptyline (50mg, 2-3 times/day), acetazolamide (125-250mg, 3-4 times/minute or 250mg at bedtime) and theophylline (100-200mg, 2-3 times/day) 3, oxygen therapy: can correct hypoxemia, and can reduce the number of apnea and hypoventilation in patients secondary to congestive heart failure, and can potentially exacerbate neuromuscular diseases Hypercapnia, but if combined with OSAHS may aggravate obstructive apnea. 4.Assisted ventilation therapy: for serious patients, the application of mechanical ventilation can enhance spontaneous breathing, and non-invasive positive pressure ventilation and invasive mechanical ventilation can be used. (B) Treatment of obstructive sleep apnea hypoventilation syndrome 1, general treatment: (1) weight loss: diet control, drugs and surgery. (2) Sleep position change: side sleep, elevate the head of the bed. (3) Abstain from smoking and alcohol, avoid taking sedatives. 2, drug treatment: the effect is not certain. Acetazolamide can be tried. Modafinil is effective in improving daytime sleepiness, and it is applied to patients whose sleepiness symptoms do not improve significantly after receiving CPAP treatment. 3.Instrumental treatment 4.Surgical treatment: (1) Nasal surgery (2) palatal droop soft palatopharyngoplasty (3) laser-assisted pharyngoplasty (4) cryogenic radiofrequency ablation (5) orthognathic surgery.