All patients received PCIA consisted of continuous background infusion(CBI) of 1 ml/h and patient-controlled analgesia(PCA) of 1 ml bolus with 15 min of locking time.

• 病人清醒后开始静脉吗啡自控镇痛 ,背景量 1ml/h ,自控量 (PCA) 1ml,锁定时间 15min。