1. The study population was recruited by the principal investigator under strict control, and 130 patients with obstructive sleep apnea hypopnea syndrome (diagnosed as OSAHS by polysomnography monitoring) who underwent painless gastroenteroscopy since the same day were selected. They were informed and agreed to this clinical trial.2. Sample size calculation:According to the pre-test results, the incidence of hypoxia in the test group and the control group were 0.2 and 0.5, respectively. The sample size was calculated using PASS software, and the bilateral test level α=0.05 and the test efficacy power=0.9 were set. 52 cases were required in each group according to the incidence of hypoxia, and 65 cases in each group were calculated after considering 20% shedding rate, totaling 130 cases.3. Specific study contents: Study participants entered the examination room to establish venous access, and used 2% lidocaine gel 5ml containing mouthwash and pharynx.Heart rate (HR), pulse oxygen saturation (SpO2), end-expiratory carbon dioxide, IPI (composite lung index), ECG monitoring, and non-invasive blood pressure (measured every 2.5 minutes) were routinely monitored before anesthesia induction.Ask patient to lie on left side.In this study, the investigators planned to implement simple randomization using SAS: (1) The group using the new oropharyngeal airway (test group) : Oxygen was continuously supplied through a catheter partially attached to the endoscopic mouth before induction of anesthesia until the end of gastroenteroscopy.(2) In the conventional endoscopic bite group (control group), oxygen was continuously supplied through a common nasal catheter before induction of anesthesia until the end of gastroenteroscopy.The entire trial operation process was completed by the investigators participating in the clinical trial.Before induction of anesthesia, study participants in the experimental group received 5-6L/min of oxygen for about 1 minute through an endoscopic biting oxygen supply device, and participants in the control group inhaled 5-6L/min of oxygen for about 1 minute through a nasal catheter.Propofol 3mg/kg and sufentanil 7μg were used to induce anesthesia in both groups.Sufentanil was given at the beginning of pre-oxygen inhalation, and propofol was given 1min later. When participants achieved sufficient sedation (about BIS40), the new oropharyngeal airway group was placed into the oropharyngeal airway through the endoscopic bite and then began gastroscopy.The ordinary endoscopic bite group began to perform endoscopic operation after sufficient sedation was achieved.In both groups, 5mg/kg·h propofol was injected continuously to maintain anesthesia until the examination was completed.If participants showed frowning or slight body movement during diagnosis and treatment, 40 to 50mg of propofol was added intravenously.If HR \< 50 times/intravenous injection of atropine 0.5mg;MAP \< 60mmHg intravenous hydroxyamine 1mg;When SpO2 \< 92%, artificial airway intervention such as jaw support, assisted breathing or mask was given.After the examination, study participants were not allowed to leave the examination room until they had a MOAA/S score of 3-4.If the sedation/anaesthesia Discharge rating scale scores more than 9 points, patients can be accompanied by relatives and friends.The incidence of hypoxia (75%≤SpO2 \< 90%, ≤60s) and severe hypoxia (SpO2 \< 75% or 75%≤SpO2 \< 90%, ≥60s) during anesthesia were recorded.The incidence of choking, reflux aspiration and laryngeal spasm were recorded.The time of intervention was half or disappearance of end-expiratory carbon dioxide and/or disappearance of thoracic fluctuation and/or SpO2 \< 95%, that is, opening the airway successively until SpO2≥95%, and recording the last means of opening the airway.The means of opening the airway of the two groups were the same, including: 1) adjusting the oxygen flow;2) Lift the lower jaw;3) Mask ventilation (pull out the gastroscope if necessary);4) Tracheal intubation or laryngeal mask for ventilator assisted ventilation.