I. Definition Obstructive sleep apnea hypoventilation syndrome (OSAHS) in children refers to a series of pathophysiological changes caused by frequent partial or total upper airway obstruction during sleep, which disrupts the normal ventilation and sleep structure during sleep. The common clinical causes of OSAHS in children: (a) Factors affecting upper airway resistance or compliance. Nasopharynx and oropharynx: The most common causes are tonsillar hypertrophy and adenoid hypertrophy, other causes are tongue hypertrophy, fat accumulation due to obesity, pharyngeal and nasopharyngeal masses, and palatopharyngeal flap surgery, etc. Most commonly seen in children over 2 years of age. 1.Nose: The nose is the second common cause, such as having chronic rhinitis (infectious, allergic), deviated nasal septum, nasal polyps, posterior nostril atresia and nasal masses. 2.Larynx: congenital laryngeal cartilage softening, laryngeal webbing, tracheal atresia, etc., mostly seen in infants and children. 3.Craniofacial anomalies: mid-facial (mid-facial) dysplasia (Down syndrome, Grouzon syndrome, chondrodysplasia), mandibular dysplasia (Pierre-Robin syndrome, Treacher-Collin syndrome, Shy-Drager syndrome, etc.), mucopolysaccharidosis (Hunter’s syndrome, Hurler’s syndrome and other syndromes), and metabolic diseases (osteosclerosis). (ii) Factors affecting neuromodulation generalized hypotonia (Down’s syndrome, neuromuscular diseases), application of sedative drug therapy, alcohol consumption, etc. (iii) OSAHS symptoms in children Sleep snoring, open-mouth breathing, repeated awakening during sleep, dyspnea, enuresis, hyperhidrosis, hyperactivity, etc. Daytime sleepiness may occur, but is uncommon. In severe cases, cognitive deficits, behavioral abnormalities, developmental delays, cardiopulmonary disorders and other complications may occur. IV. Complications of OSAHS Untreated OSAHS can lead to serious complications. Probably because of the early diagnosis and treatment of this disease nowadays, serious complications such as growth disorders, cardiopulmonary complications, and mental retardation previously reported in the literature are uncommon. The literature has reported a trend of accelerated height and weight growth in children with OSAHS with growth disorders after adenoidectomy and tonsillectomy. Prolonged open-mouth breathing can result in significant maxillofacial developmental deformities DD “adenoid facies”. Severe cases can lead to hypertension, pulmonary hypertension, and even right heart failure, and related studies have found that the disease is closely associated with sudden infant and child death. Studies have shown that children with OSAHS have high risk factors, such as recurrent tonsillitis, obesity, Down syndrome, and neurocognitive deficits, such as learning difficulties, abnormal behavior, and attention deficits. Recent studies have shown that children with sleep disordered breathing disorders have poor academic performance, and many have improved academic performance after adenotonsillectomy. V. Diagnostic methods Diagnostic methods include medical history, physical examination, lateral nasopharyngeal radiography, fiberoptic nasopharyngoscopy, snoring sound recording, application of video, pulse oximetry, and multichannel sleep monitoring (PSG). Currently, nocturnal multichannel sleep monitoring is the standard method for diagnosing sleep breathing disorders and can be performed in children of any age. Children who are not in a position to undergo PSG can refer to audio, video, and pulse oximetry to assist in diagnosis. The purpose of performing PSG examination is: j to distinguish simple snoring, from obstructive sleep apnea hypoventilation syndrome; k to determine the diagnosis of OSAHS; l to evaluate the severity of OSAHS; m to assess the postoperative outcome; n to diagnose central apnea and alveolar hypoventilation; o to assess sleep architecture and non-breathing related sleep disorders (e.g. nocturnal seizures, etc.). Obstructive sleep apnea (obstructivesleepapnea,OSA) is the cessation of oral and nasal airflow during sleep, but thoracic and abdominal breathing is still present. Hypopnea (hypopnea) is defined as a 50% reduction in peak oral and nasal airflow signals with a 3% or greater decrease in oxygen saturation and/or arousal (microarousal). In contrast, the length of a respiratory event (including apnea and hypoventilation) was defined as greater than or equal to two respiratory cycles. (Two respiratory cycles are practically difficult to operate when analyzing PSG, and the duration of two respiratory cycles varies in the same individual, preferably with a fixed time limit, such as 5s or 6s, as in adults.) Multichannel sleep monitoring examination: OAI (obstructive sleep apnea index) greater than, or equal to, 1 or AHI (sleep apnea hypoventilation index) greater than 5 during each night’s sleep is considered abnormal, and a minimum blood oxygen A minimum oxygen saturation of less than 92% is defined as hypoxemia. Other examinations: X-ray chest film and electrocardiogram can help to exclude right ventricular hypertrophy and cardiopulmonary disorders; lateral nasopharyngeal X-ray or CT can help to determine the site of airway obstruction; fiberoptic nasopharyngoscope can dynamically observe the upper airway stenosis, and at the same time, it can visually understand the adenoid hypertrophy and nasal cavity, which can give the doctor a sense of clarity at a glance. Treatment methods (a) Surgical treatment Adenoidectomy and tonsillectomy Adenoidectomy is the most common first-line treatment for OSAHS in children, with an efficiency of 90%. When both tonsils and adenoids are enlarged, adenoidectomy or tonsillectomy alone is not sufficient and the results are not satisfactory. Other studies have shown that in children with otherwise healthy adenoids and tonsils (e.g., simple snoring), 75% to 100% of children with adenoids and tonsils improved their PSG after adenoidectomy, along with the disappearance of the corresponding symptoms. Although the outcome of obese children after surgery is not satisfactory, most obese children can be effectively treated by adenoidectomy. Other surgical treatments include uvulopalatopharyngoplasty, craniofacial orthognathic surgery, inferior turbinate reduction, and in severe cases, tracheotomy. However, treatment such as uvulopalatopharyngoplasty and tracheotomy may affect the growth and development of children and their quality of life, so great care should be taken. (ii) Non-surgical treatment Continuous positive airway pressure ventilation (CPAP) is an optional treatment for patients with contraindications to surgical procedures, small adenoid tonsils, OSAHS still present after adenoid tonsillectomy, and those who choose non-surgical treatment. pressure titration of CPAP must be done in the sleep laboratory and needs to be adjusted periodically. Other treatments for rhinitis, in children with inferior turbinate hypertrophy, may include submucoperiosteal bone churning or fracture outgrowth or partial mucosal resection or reduction fusion therapy of the inferior turbinate in conjunction with general anesthesia surgery. The treatment of rhinitis, allergic rhinitis and sinusitis should be systematic and standardized before and after surgery. Weight loss in obese patients. Oral orthodontic appliances (maxillofacial deformities can be corrected by orthodontics), only for patients who have caused maxillofacial deformities or are unwilling to receive surgical treatment or cannot be treated surgically. VII. Efficacy assessment Follow-up time: All patients should be followed up clinically after initial treatment. Recent follow-up: A re-evaluation is recommended 6 to 8 weeks (8 weeks) after surgery. At this time the reshaping of the upper airway, heart, and central nervous system has been completed. Long-term follow-up: 3 to 6 months (6 months) or more.