[Opiates for epidural analgesia: for or against?].

Epidural opiate administration is routinely used by many anaesthesiologists involved in obstetric anaesthesia. Epidural injection of a local anaesthetic combined with an opioid generates a more rapid onset of more profound analgesia with little motor blockade. Thus pain relief lasts longer than after either drug alone. A combination of dilute concentrations of bupivacaine and opioids lowers the risk of systemic local anaesthetic toxicity significantly. Fentanyl was the first opioid widely used as an adjunct to local anaesthetics for labour analgesia. An initial dose of fentanyl 50 micrograms combined with 0.25% or 0.125% bupivacaine can produce good initial analgesia for most laboring parturients. A continuous infusion of 0.125% or 0.0625% bupivacaine with 1 microgram.ml-1 fentanyl at 10-12 ml.h-1 will maintain good pain relief throughout parturition. No adverse effects on either the mother or the neonate have been attributed to this technique. Recently, sufentanil was introduced in obstetric analgesia. Sufentanil appears to induce a faster onset of more profound, long lasting analgesia with extremely low concentrations of bupivacaine than that with fentanyl. The reduction of the total amount of bupivacaine is correlated with a significant decrease in motor blockade and instrumental deliveries. There were no adverse maternal or fetal effects and umbilical cord levels were too low to be detected.