///2016 Abstract Details
2016 Abstract Details2019-07-15T10:10:51-05:00

Programmed intermittent epidural bolus for labor analgesia during first stage of labor: A sequential trial to determine the optimum interval time between boluses of a fixed volume of 10 ml of bupivacaine 0.0625% plus fentanyl 2 mcg/ml

Abstract Number: GM-01
Abstract Type: Original Research

Marcelo Kanczuk MD 1 ; Nicholas Barrett MD2; Cristian Arzola MD MSc3; Kristi Downey MSc4; Xiang Ye MSc5; Jose Carvalho MD PhD6

Introduction: Most studies comparing Programmed Intermittent Epidural Bolus (PIEB) with Continuous Epidural Infusion regimens have included patient controlled epidural analgesia (PCEA) and/or manual bolus as rescue analgesia for breakthrough pain (1,2). Consequently, the optimal time interval between programmed intermittent boluses is yet to be determined. We designed a study to establish the optimal time interval between programmed intermittent boluses of 10 ml of bupivacaine 0.0625% with fentanyl 2 mcg/mL to produce effective analgesia in 90% of women during first stage of labor without the need of rescue boluses.

Methods: We conducted a double-blind sequential trial with a biased coin up-down design to obtain the effective interval 90% (EI90) for the PIEB regimen. We included ASA 2-3 nulliparous women at term undergoing spontaneous or induced labor requesting epidural analgesia. An ultrasound-assisted epidural was inserted at L2/3 or L3/4. A test dose of 3 ml of bupivacaine 0.125% plus fentanyl 3.3 mcg/ml was followed by a loading dose of 12 ml of the same solution. PIEB was then started in women whose pain scores achieved VNRS ≤ 1/10 within 20 min after the loading dose. In all subjects the programmed bolus dose was fixed at 10 mL, and the first bolus was delivered 1 hour after the loading dose. The PIEB interval was set at 60 min for the first patient and at varying time intervals (60, 50, 40 and 30 minutes) for the subsequent patients, according to a biased coin design. The primary outcome was effective analgesia, defined as no requirement for a PCEA or a manual bolus for 6 hours after the initiation of the epidural or until the patient was fully dilated, whichever event occurred first. Pain scores, sensory block levels to ice, degree of motor block and blood pressure were assessed hourly.

Results: We studied 40 women. The calculated EI90 was 42.6 min (95% CI: 38.9 - 46.4) using the Dixon and Mood method and 36.8 min (95% CI: 31.0 - 49.0) using the Isotonic Regression analysis. Peak sensory levels, degree of motor block and incidence of hypotension in each subgroup is presented in table 1.

Discussion: The optimal time interval between programmed intermittent boluses of 10 mL of bupivacaine 0.0625% with fentanyl 2 mcg/mL is approximately 40 minutes. Further studies to determine the efficacy of this regimen throughout the entire duration of labor are warranted.

References: 1) Can J Anesth 2004; 51: 581-585; 2) Int J Obstet Anesth 2005; 14: 305-309

SOAP 2016