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.