///2009 Abstract Details
2009 Abstract Details2018-05-01T17:45:11+00:00

PRURITUS FOLLOWING EPIDURAL FENTANYL ADMINISTRATION WITH BUPIVACAINE FOR INDUCTION OF LABOR ANALGESIA: A PROSPECTIVE RANDOMIZED CONTROLLED STUDY

Abstract Number: 53
Abstract Type: Original Research

Malorie Letourneau MD1 ; Julie M Bedard MD FRCPC2; Alexis F Turgeon MD MSc FRCPC3

Introduction: During induction of labor epidural analgesia (LEA), doses of 50 to 100g of fentanyl are commonly used in combination with bupivacaine. Epidural fentanyl can cause pruritus. However, its incidence according to dosage or timing of injection is unknown(1,2). We hypothesized that a dose of 50g of epidural fentanyl at induction of LEA would reduce the incidence of pruritus while achieving adequate analgesia in comparison with a dose of 100g.

Methods: In this prospective randomized controlled study, ASA I or II term singleton parturients were recruited during labor when they requested LEA. They were randomly distributed in 2 groups: fentanyl 50g (F50) or fentanyl 100g (F100). Patients with a prior history of pruritus were excluded (3). A 4mL solution of fentanyl 50 or 100g was prepared by our hospital pharmacist and added to a 12mL solution of bupivacaine. A total volume of 16mL of a final concentration of bupivacaine 0.125% was injected for induction of LEA. Pruritus and analgesia were evaluated using a 100mm Visual Analog Scale (VAS) 5 minutes before injection, and at 10, 20, 30, 45 and 60 minutes. The primary outcome was the incidence of pruritus at 60 minutes. Secondary outcomes were the incidence of pruritus at 10, 20, 30 and 45 minutes after injection and analgesia at these same time intervals. Pruritus was defined as a value ≥10mm on the VAS, while adequate analgesia was defined by a value <30mm. Based on an incidence of 50% of pruritus with epidural fentanyl 100g from a local pilot study (n=15), 132 patients were required to detect a decrease in the incidence of pruritus from 50% in group F100, to 25% in group F50 allowing Type I and II error of 5% and 20%, respectively. Statistical analyses were performed using the Fishers exact test and a p value <0.05 was considered significant.

Results: Following REB approval and written informed consent, 140 women were enrolled. Three were excluded following failure of LEA. Thus, 137 patients completed the study: 69 in group F100 and 68 in group F50. Demographics were comparable between groups. At 60 minutes, 43%[95%CI:30-53] of patients in group F50 had pruritus in comparison with 76%[95%CI:65-85] in group F100 (p<0.01). The incidence was also lower in group F50 at 45 minutes(38%[95%CI:28-50] vs. 66%[95%CI:53-76], p<0.01), but comparable at other time intervals. Pain control was comparable between groups up to 60 minutes following injection.

Discussion: In this study, we observed that a dose of 50g of epidural fentanyl at induction of LEA reduced the incidence of pruritus in comparison with a dose of 100g without impeding analgesia. A 50g dose of fentanyl should be favored over a 100g dose for induction of LEA.

References:

1. Anesthesiology 2000 92: 280-1

2. Anesth Analg 1993 77: 919-24

3. J Am Acad Dermatol 2006 54: 395-404.

SOAP 2009