Intervention
In PCV group, mechanical ventilation begun with PIP = 15 mmHg, RR = 12/min, I/E = ½, and PEEP = 3. Then the PIP was adjusted to achieve a tidal volume that was calculated as the ideal body weight (50 [female: 45.5] + 0.91 [height − 152.4]) × 7 ml. In addition, the respiratory rate was controlled, using the end-tidal carbon dioxide pressure (ETco2) ranged from 35 to 40 mmHg.In VCV group, TV was set as 7 ml/IBW; however, RR, I/E, and PEEP were chosen as PCV group. Afterward, anesthesia was reversed with 0.04 mg/kg neostigmine and 0.02 mg/kg atropine.