5Woolf CJ.Recent advance in the pathophysiology of acute pain[J].Br J Anearth,1989,63(2):139.
6Kissin I.Preemptive analgesia;why its effect is not always obvious[J].Anestesiology,1996,70(3):434.
7Dahl JB,kehlet H.The value of preemptive analgesia in the treatment of postoperative[J].Br J Aneath,1993,70(3):434.
8Woolf CJ.The induction and maintenance of central sensitization is dependent on NMDA receptor activation[J].Pain,1991,44(3):293.
9Aida S,Yamakura T,BabaH,et al.Preemptive analgesia by intravenous low-dose ketamine and epidursl morphine in gastrectomy: a randomized double-blind study[J].Anesthesiology,2000,92:1624-1630.
10Semple D,Findlow D.The optimal dose of ketamine for caudal epidural blockade in children[J].Anaesthesia,1996,51:1170-1172.