///2015 Abstract Details
2015 Abstract Details2019-08-02T16:54:43-06:00

Onset of labor epidural analgesia with varying doses of fentanyl

Abstract Number: O1-04
Abstract Type: Original Research

Fatemah A. Qasem MD1 ; Don Nguyen MD2; Sudha Indu Singh MD, FRCPC3; Philip M Jones MD, MSc, FRCPC4; Kristine Marmai MD, FRCPC5; Ramesh Sai MD6


Low concentrations of local anesthetic with opioids are commonly used for labor epidural analgesia, as they provide pain relief without much motor block. However, onset of analgesia may be delayed compared to more concentrated solutions. A comparison study was conducted using different doses of fentanyl (20, 50, 100 mcg) with low dose bupivacaine (0.08%) to investigate the onset of labor analgesia. Our hypothesis was that onset of analgesia would be faster with the higher doses of fentanyl.


Institutional REB approval was obtained as was written informed consent from all participants in the study. We conducted a prospective, randomized, double-blinded study of 105 patients with singleton pregnancy at term gestation in early labor, requesting epidural analgesia. Women were randomized to receive induction of epidural analgesia with one of three doses of fentanyl (20, 50, or 100 mcg) and 10 mL of 0.08 % bupivacaine. Numeric Rating Scale (NRS) scores for pain were monitored with each contraction; the primary outcome was the time taken to achieve a NRS score ≤3. The onset and duration of analgesia, maternal side effects and satisfaction, type of delivery, and fetal outcomes were recorded.


Data from 105 patients were analyzed (Table). Demographic data were similar among groups. The 50 and 100 mcg fentanyl doses were associated with faster development of NRS ≤3 compared to the 20 mcg fentanyl group. The incidence of failure to reach NRS ≤3 within 30 minutes was higher in the 20 mcg group compared to both other groups. There was no difference in maternal satisfaction or adverse events between groups, except for a higher incidence of fetal bradycardia in the 50 mcg and 100 mcg fentanyl groups. However, APGAR scores at 1 minute and 5 minutes were not different between different groups.


Higher doses of epidural fentanyl speed the onset of analgesia for laboring parturients without increasing maternal adverse events.

SOAP 2015