3Lawrenca C, Brad T, Sanjay C,et al. Is combined spinal-epidural analgesia associated with more rapid cervical dilation in nulliparous patients when compared with conventional epidural analgesia? Anesthesiol, 1999,91:920-925.
4James A, Daniel H, Rene M, et al. The effect of intrapartum epidural analgesia on nulliparous labor: a randomized controlled prospective trial. Am J Obstet Gynecol, 1993,169:851-858.
5Halpern SH, Leighton BL, Ohlsson A, et al. Effect of parenteral opioid analgesia on the progress of labor: a meta-analysis. JAMA, 1998,280:2105-2110.
6Cutbush CM, McDonough JP, Clark K, et al. The effect of intrathecaj and epidural narcotic analgesia on the length of labor. CRNA, 1998, 9:106-112.
7Chestnut DH, Vandewalker GE, Owen CL, et al. The influence of continuous epidural bupivacaine analgesia on the second stage of labor and method of delivery in nulliparous women. Anesthesiol, 1987,66:774-780.
8Gartier P, DeKock M, Van Steenberge L, et al. A double-blind comparison of 0.125% ropivacaine with sufentanil and 0.125% bupivacaine with sufentanil for epidural analgesia. Anesthesiol, 1999,90:772-778.
9Collis RE, Harding SA, Morgan BM. Effect of maternal ambulation on labor with low-dose combined spinal-epidural analgesia. Anesthesiol, 1999,90:634-640.
10Irestedt L, Ekblom A, Olofsson C, et al. Pharmacokinetics and clinical effect during continous epidural infusion with ropivacaine 2.5 mg/ml or bupivacaine 5 mg/ml for labor pain relief. Acta Anaesthesiol Scand, 1998,42:980-996.