7Moiniche S,Kehlet H,Dahl JB.A qualitative and quantitative systematic review of preemptive analgesia for postoperative pain relief:the role of timing of analgesia.Anesthesiology,2002,96:725-741.
8Ong CK,Lirk P,Seymour RA,et al.The efficacy of preemptive analgesia for acute postoperative pain management:a meta-a-nalysis.Anesth Analg,2005,100:757-773.