One of the most common adverse events during sedated gastrointestinal endoscopy is hypoxemia, which can lead to serious consequences. When sedated gastrointestinal endoscopy is performed in high-altitude regions with thin air and lower atmospheric pressure, the risk of hypoxemia in patients significantly increases. Traditionally, propofol is the primary agent for sedation during gastrointestinal endoscopy, offering rapid onset and recovery. However, propofol has many side effects, the most important of which is inhibition of respiration and hypotension. Etomidate has less effect on respiration compared to propofol. But there are also adverse reactions of etomidate such as muscular tremor, nausea and vomiting. This study aims to explore whether the etomidate combined with propofol anesthesia method can reduce the risk of hypoxemia during sedated gastrointestinal endoscopy in high-altitude regions, compared to the traditional propofol anesthesia method .

Inclusion Criteria:

Age: 18 ≤ years ≤ 70 Patients undergoing pain-free gastroscopy or treatment Endoscopy duration within 30 minutes Informed consent obtained from patient or family member

Exclusion Criteria:

Concomitant diagnosis of cardiac diseases (e.g., heart failure, angina, myocardial infarction, arrhythmia) Diagnosed pulmonary diseases Liver diseases Kidney diseases Intracranial hypertension ASA class III or higher Concomitant active upper respiratory tract infection