Remifentanil: a novel systemic analgesic for labor pain

In a double-blind, randomized, controlled clinical trial, we compared the analgesic effect of remifentanil in patient-controlled IV analgesia (PCIA) during labor and delivery with the effect of an IV infusion of meperidine. Eighty-eight healthy term parturients who requested IV analgesia for labor pain were enrolled in the study and were randomly assigned to receive either increasing doses (0.27-0.93 microg/kg per bolus) of PCIA remifentanil (n=43) or an IV infusion of meperidine 150 mg (range, 75-200 mg) per patient (n=45). Remifentanil by the PCIA device was more effective and reliable analgesia for labor and delivery than IV infusion of meperidine. The visual analog score was lower (35.8 +/- 10.2 versus 58.8 +/- 12.8; P <0.001) and the patient satisfaction score higher (3.9 +/- 0.6 versus 1.9 +/- 0.4; P <0.001), with less of a sedative effect (1.2 +/- 0.1 versus 2.9 +/- 0.1; P <0.001) and less hemoglobin desaturation (97.5% +/- 1.0 versus 94.2% +/- 1.5; P <0.007). The percentage of analgesia failure (the rate of crossover from opiate to epidural analgesia) was less for remifentanil compared with meperidine (10.8% versus 38.8%; P <0.007). There were no significant differences between groups in the mode of delivery or neonatal outcome. There were fewer nonreassuring abnormal fetal heart rate patterns, i.e., higher variability and reactivity with fewer decelerations, under remifentanil therapy as compared with meperidine (P <0.001). In conclusion, an intermittent incremental regimen with repeated small-dose PCIA boluses of remifentanil provided effective and reliable analgesia during labor and delivery.