The Comparison of Postoperative Pain After Lumbar Fusion Surgery in Intravenous Patient-controlled Analgesia Between Conventional Mode and Optimizing B.I Mode With 'PAINSTOP' Equipment

In the intervention group, the optimizing B.I PCA mode will be setted. This mode is setted that the amount of administered drug per hour will be increased by 0.3 ml by pressing bolus button (The interval: \~ 8 hr: 2 - 4 ml, 8-24 hr: 1 - 3 ml, 24 hours \~ : 0.5 - 2.5 ml). Conversely, if the bolus button is not used for 90 minutes, the administered amount of drug per hour is setted to be reduced by 0.1 ml, and the maximum (or minimum) allowable flow rate is 4 ml (or 0.5 ml).

Mode setting; total volume: 150 ml, flow rate: 2 ml, bolus volume: 0.5 ml, and LOT: 10 minutes