The Programmed Intermittent Epidural Bolus Adrenaline Study (PIEBA)

This study evaluates the use of intermittent epidural boluses compared to continuous infusion in maintaining epidural pain relief in labor. The medicine solution used contains, in addition to bupivacain and fentanyl, adrenalin in both groups.

Labor is often painful for the woman going through it, and thus many women choose to have pain relief by an epidural catheter. This is done by placing a thin plastic catheter in the epidural space in the lower back of the patient, and injecting a medicine solution usually consisting of local anesthesia and opioids. To ensure an effective pain relief through the labor process, additional medicine solution is injected through the catheter. Traditionally, this is done by a continuous infusion, often with the addition of patient controlled boluses. In this study the investigators investigate if maintaining the pain relief through programmed hourly intermittent boluses is more effective than continuous infusion. This is done in other studies with promising results, but the difference in this study is the addition of adrenaline to the medicine solution in order to make it more effective.

Bolus of 5 ml every hour + patient controlled extra boluses of 5 ml, maximum 3 / hour. Medicine solution is bupivacaine 1 mg/ml, fentanyl 2 mcg/ml, adrenaline 2 mcg/ml.

Continuous epidural infusion of 5 ml / hour + patient controlled extra boluses of 5 ml, maximum 3 / hour. Medicine solution is bupivacaine 1 mg/ml, fentanyl 2 mcg/ml, adrenaline 2 mcg/ml.

Cumulative drug consumption is assessed at the end of treatment (at birth). The total dose is adjusted for differences in treatment time and other possible factors of influence (BMI, parity, age, gestational age etc.)

Mode of delivery will be assessed and categorized as vaginal,instrumentally assisted or cesarean delivery.

The need for additional anesthesiologic intervention, including time to this intervention from start of treatment.

Expected adverse events include hypotension (systolic blood pressure < 90 mmHg and/or use of vasopressors), nausea (mild/moderate/severe) and pruritus (mild/moderate/severe).

Adverse events during treatment (0-24 hours) and final assessment within 24 hours of end of treatment

Pain rating will be assessed using a numeric rating scale (NRS, 0-10; 0= no pain, 10=worst imaginable pain) before treatment start, at every hour for the first 8 hours of treatment and every other hour thereafter. Worst pain at delivery will also be assessed.

Inclusion Criteria: Pregnant women in labor requesting epidural analgesia ASA group 1 and 2 0 or 1 previous births Must be at least 18 years of age. Singleton pregnancy Active labor Signed informed consent and expected cooperation of the patient Exclusion Criteria: Poor communication skills in norwegian or english Adverse reactions to local anesthetics or synthetic opioids Body height below 150 cm Gestational age below 37 weeks, 0 days Any contraindication to epidural catheter placement (e.g. patients with coagulopathy, infection in area etc) Pre-eclampsia Sound reason by the investigator to suspect patient non-compliance (e.g. with use of PCEA)

George RB, Allen TK, Habib AS. Intermittent epidural bolus compared with continuous epidural infusions for labor analgesia: a systematic review and meta-analysis. Anesth Analg. 2013 Jan;116(1):133-44. doi: 10.1213/ANE.0b013e3182713b26. Epub 2012 Dec 7. Erratum In: Anesth Analg. 2013 Jun;116(6):1385.