For induction, 25 mg of meperidine and 2.5 mg of midazolam were administered. To maintain conscious level of patient at moderate or deep level, 25 mg of meperidine and/or 2.5 mg of midazolam were administered as necessary.

For induction, 25 mg of meperidine and 2.5 mg of midazolam were administered. To maintain conscious level of patient at moderate or deep level, 1% propofol at the rate of 1 mg/kg/hr was administered. An additional 0.5 mg/kg bolus was administered as needed to achieve the designed conscious level.

For induction, 25 mg of meperidine and 2.5 mg of midazolam were administered in both groups. In the cocktail group, one milligram per kilogram body weight of 1% propofol emulsion (Baxter Healthcare Corp., Irvine, CA) was slowly infused by an automated pump (Terufusion syringe pump TE-331, Terumo Corporation, Tokyo, Japan). To maintain conscious level of patient in the conventional group to be at moderate or deep level, 25 mg of meperidine and/or 2.5 mg of midazolam were administered as necessary, whereas patients in the cocktail group were continuously administered with 1% propofol at the rate of 1 mg/kg/hr. An additional 0.5 mg/kg bolus was administered as needed to achieve the designed conscious level.

(1) induction time (the time from sedation to scope intubation), (2) procedural time (the time from scope intubation to scope withdrawal), and (3) recovery time (the time from scope withdrawal to full recovery (modified Aldrete score of 10)). The induction time and procedural time were recorded by the nurse in the endoscopy unit.

(1) hypotension (systolic blood pressure drops to less than 90 mmHg or decreases more than 25% from the baseline), (2) bradycardia (heart rate <40 beats/min), (3) desaturation (oxygen saturation <90% for >10 seconds), and (4) apnea (cessation of respiratory activity for over 10 seconds under visual observation). If the oxygen saturation dropped to <85% for more than 30 seconds despite oxygen supplementation or apnea occurred, the procedure would be interrupted and reversal medications would be given to the patient.