Umbilical analgesic concentrations after labour analgesia with programmed intermittent epidural bolus: a prospective observational study.

Abstract

Purpose: The umbilical analgesic concentrations after using programmed intermittent epidural bolus (PIEB) and patient-controlled epidural analgesia (PCEA) without continuous infusion are unknown. We aimed to characterize umbilical ropivacaine and fentanyl concentrations and examine their influence on neonatal conditions at delivery.

Methods: We prospectively studied 50 parturients with singleton pregnancies who received combined spinal-epidural analgesia using PIEB (7 mL every 45 min) and PCEA (7 mL per bolus; lockout interval: 15 min) with 0.08% ropivacaine and 2 μg·mL^-1 fentanyl, with clinician-administered boluses as necessary. We evaluated the umbilical venous analgesic concentrations and neonatal characteristics.

Results: The median [interquartile range (IQR)] hourly ropivacaine and fentanyl doses were 13 [11-15] mg·hr^-1 and 39 [30-50] µg·hr^-1, respectively. The ropivacaine and fentanyl concentrations were 77 [56-98] ng·mL^-1 and 0.125 [0.125-0.20] ng·mL^-1 at delivery, respectively. The umbilical analgesic concentrations were correlated with the labour duration and total dose. In parturients given clinician-administered boluses within 1 hr before delivery, the ropivacaine and fentanyl concentrations were similar to those without (81 [54-104] vs 77 [54-96] ng·mL^-1 and 0.20 [0.125-0.20] vs 0.125 [0.05-0.20] ng·mL^-1, respectively). The umbilical arterial pH was > 7.2 and the Apgar score at 5 min was ≥ 8 for all neonates. No neonates exhibited systemic local anesthetic toxicity. Respiratory support was required for 14 neonates.

Conclusions: Umbilical analgesic concentrations at delivery were low after labour analgesia using a regimen of PIEB with PCEA for up to 19 hr. An intermittent bolus dosing regimen may contribute to a decrease in umbilical analgesic concentrations.