Clinical Research Directory

Inclusion Criteria: Patients who receiving gastroscopy under general anesthesia, accompanied with one of the following risk factors of hypoxia: 1. Patients combined with heart or respiratory diseases 2. Age older than 60 3. ASA grading II-III 4. BMI≥30kg/m², 5. Snoring or having sleep apnea syndrome 6. Patients with a STOP-Bang score ≥ 3 (the risk of OSAS is high) are considered to be highly risk of hypoxia. Exclusion Criteria: 1. Severe cardiovascular, pulmonary, liver, or kidney disease 2. Patients with infections or tumors of airway 3. History of difficult intubation under general anesthesia 4. Severe sleep apnea syndrome \[hypopnea/apnea hypopnea index (AHI)\>40\] 5. Patients allergic to propofol, eggs, soy or egg whites 6. Pregnancy