2[1]Knudsen K, Surkula MB, Blomberg S, et al. Central nervous and cardiovascular effects during iv infusions of ropivacaine and bupivacaine in volunteers[J]. Br J Anaesth, 1997,78:507-514.
3[2]Bernard JM, LeRouv D, Vizquel L, Patient-controlled epidural analgesia during labor: The effects of the increase in bolus and lockout interval [J]. Anesth Analg, 2000, 90(2):328- 332.
4[3]Carstiniu J, Lerytam S, Norman P, et al. Nitrous oxide in early labor safety and analgesic efficacy assessed by a double and placebo controlled study [J]. Anesthesiology, 1996, 80:30 -35.
5[4]Rosen MA. Nitrous oxide for relief of labor pain: A systematic review [J]. Am J Obstet Gynecol 2002,186(2) :S110 - 126.
6[5]Garc MM, Laez VJ, Sevilapma B, et al. Analgesic effectiveness and fentanyl in continous perfusion[J]. Rev Esp Anesthesiol, 1997,44:135 - 139.
7[6]Vallejo MC, Firestone LL, Mandell Gl, et al. Effect of epidural analgesia with ambulation on labor duration [J ]. Anesthesiology, 2001,95(4) :857 - 861.
8[7]Polley LS, Columb MO. Comparison of epidural ropivacaine and bupivacaine in combination with sufentanil for labor[J].Anesthesiology, 2000,92 : 280 - 281.
9[8]Muir HA, Writer D, Douglas J, et al. Double blind comparison of epidural ropivacaine 0.25% and bupivacaine 0.25 %, for the relief of childbirth pain[J]. Can J Anaesth, 1997,44:599-604.
10[9]Asselineau D. Does ambulation under epidural analgesia during labor modify thecondtion of fetal extraction [ J ]. Contracept Sex, 1996,24: 505 -507.
