Remifentanil by patient-controlled analgesia compared with intramuscular meperidine for pain relief in labour.

Background: The pharmacokinetics of remifentanil suggests that it may be suitable for analgesia during labour.

Methods: In an open pilot study, 36 women requesting meperidine for analgesia were recruited early in labour and randomized to receive either meperidine i.m. or remifentanil given as patient-controlled analgesia (PCA). Pain severity, sedation and anxiety were assessed with visual analogue scales and overall effective analgesia was assessed by the woman and midwife.

Results: The pain scores were lower in the remifentanil group: median pain score at 60 min was 72 mm for meperidine and 48 mm for remifentanil (P=0.004) and median maximum pain score during the first 2 h was 82.5 mm for the meperidine group and 66.5 mm for the remifentanil group (P=0.009). Both the midwives' and the women's assessments of overall effective analgesia were higher in the remifentanil group [Likert scale (5 = excellent to 1 = poor): chi2=12.10, P=0.002 for mothers' assessment; chi2=12.80, P=0.002 for midwives' assessment].

Conclusion: In this pilot study, remifentanil by PCA gave better pain relief to mothers in labour than intramuscular meperidine. However, remifentanil is a potent respiratory depressant and adequate continuous monitoring is necessary.