Determine the median effective dose of propofol combined with different doses of teligirine for gastroscopy in children

INTERVENTION: Group A:Taigiliding 0µg/kg intravenous bolus;Group B:Taigiliding 5µg/kg intravenous bolus;Group C:Taigiliding 10µg/kg intravenous bolus;Group D:Taigiliding 15µg/kg intravenous bolus; CONDITION: Upper gastrointestinal endoscopy PRIMARY OUTCOME: ED50 of propofol combined with different doses of tegeglutant for upper gastrointestinal endoscopy in children; SECONDARY OUTCOME: Incidence of adverse events with different dose combinations of propofol and tegeglutant; INCLUSION CRITERIA: 1. The age must be = 6 years old and = 12 years old; 2. Gender is not limited; 3. ASA classification is grade I‐II; 4. Children who are scheduled to undergo upper gastrointestinal endoscopy under deep sedation or general anesthesia without tracheal intubation.