NEONATAL WELFARE AND PLACENTAL-TRANSFER OF FENTANYL AND BUPIVACAINE DURING AMBULATORY COMBINED SPINAL EPIDURAL ANALGESIA FOR LABOR

To investigate current concerns that potent opioid drugs, such as fent anyl, used for labour regional analgesia may affect neonatal status, m aternal and umbilical plasma concentrations of fentanyl and bupivacain e at delivery were measured in 40 nulliparous patients receiving low-d ose combined spinal epidural analgesia. Neonatal assessments included Apgar scores, umbilical blood gases and neurobehavioural tests. All ma ternal and umbilical venous plasma concentrations were low. Maternal a nd umbilical vein total fentanyl concentrations increased with increas ing doses of epidural fentanyl (r = 0.46 and 0.30, respectively, p < 0 .01). There were no significant differences between maternal and umbil ical venous plasma total or h-ee concentrations of fentanyl. Mean umbi lical vein/maternal fentanyl ratios were 1.12 for total drug and 1.20 for free drug and values were unrelated to the last epidural bolus to delivery interval (r = 0.12, p = 0.49). There were no correlations bet ween Apgar scores, umbilical blood gases or neurobehavioural scores an d umbilical venous concentrations of either fentanyl or bupivacaine. T he dose of fentanyl used for ambulatory combined spinal epidural analg esia would appear to have a negligible effect on neonatal condition.