Patients who meet the enrollment criteria were randomized 1:1 to either the BIS group or the OAA/S group.~In the BIS group, the anesthesiologist set the target controlled infusion (TCI) parameters according to the patient's height, weight, gender and age. The initial plasma target concentration was set to 1.5 ug/ml, and the target concentration would be increased or decreased 0.5 ug/ml every two minutes to maintain the BIS value at 45-60. In the OAA/S group, the target concentration would be increased or decreased 0.5 ug/ml every two minutes to maintain the OAA/S value at 1 point.~Body movement, the time of gastroscopy, endoscopist satisfaction scores to sedation, the propofol consumption during gastroscopy and the time to awake were be recorded. In addition, the event of the respiration and circulation suppression during the gastroscopy were recorded. Atropine 0.3 mg was injected intravenously if bradycardia occurred (heart rate <50 beats/min), M-hydroxyamine 0.3 mg was injected intravenously if hypotension (mean arterial pressure<65 mmHg), Ephedrine 3 mg was injected if bradycardia and hypotension occured. Patients would receive face mask-assisted ventilation if the Spo2 dropped below 90% or respiratory frequency was lower than 8 breaths/min during the gastroscopy.
Patients who meet the enrollment criteria were randomized 1:1 to either the BIS group or the OAA/S group.~In the BIS group, the anesthesiologist set the target controlled infusion（TCI）parameters according to the patient's height, weight, gender and age. The initial plasma target concentration was set to 1.5 ug/ml, and the target concentration would be increased or decreased 0.5 ug/ml every two minutes to maintain the BIS value at 45-60. In the OAA/S group, the target concentration would be increased or decreased 0.5 ug/ml every two minutes to maintain the OAA/S value at 1 point.