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54: Remifentanil patient controlled analgesia versus epidural analgesia in labor; a randomized controlled equivalence trial

      Objective

      Recent studies suggest that remifentanil patient controlled analgesia (RPCA) is equivalent to epidural analgesia (EA) with respect to pain appreciation (satisfaction with pain relief). These studies were underpowered to detect a difference in pain appreciation. The aim of our study was to compare the effectiveness of RPCA with EA regarding pain appreciation.

      Study Design

      We performed a multicenter equivalence RCT in 15 hospitals in the Netherlands (NTR 2551). We included healthy pregnant women who intended to deliver vaginally. After informed consent, they were randomized prior to the onset of active labor. Primary outcome was pain appreciation, measured hourly on a visual analogue scale (VAS), and expressed as area under the curve (AUC). The AUC gives a time-weighted measure of total pain appreciation. The AUC was calculated for the duration of labor and for the time that pain relief was administered. A higher AUC for pain appreciation represents higher satisfaction with pain (relief). Secondary outcomes were pain scores and maternal and neonatal variables.
      To exclude a clinically significant difference in pain appreciation, defined as a difference of more than 10%, we needed 1136 women. Analysis was done by intention to treat.

      Results

      709 women were allocated to RPCA and 705 to EA. Baseline characteristics were comparable. 447 (65%) women in the RPCA and 343 (51%) in the EA group received pain relief during labor (RR 1.3 95% CI 1.2-1.5). Among women allocated to RPCA 344 received nothing but RPCA, in the EA group 295 received just EA. 13% of the women switched to EA after RPCA. Maternal and neonatal outcomes were comparable. No serious adverse events occurred. The AUC for total pain appreciation during labor was 26.5 in the RPCA group versus 36.0 in the EA group (mean difference 9.5 (95% CI 5.0-13.0)).

      Conclusion

      RPCA is not equivalent to EA with respect to AUC for pain and pain appreciation scores and overall satisfaction in women with a request for pain relief during labor.
      Tabled 1Primary outcome
      Figure thumbnail fx1
      Area under the curve of pain appreciation scores, pain scores and overall appreciation score. Intention to treat analysis; analysis of scores during active labor and separate analysis of scores during administration of pain relief.