A Novel Approach to Optimize Programmed Intermittent Epidural Bolus (PIEB) Delivery for Labour Analgesia

A Novel Approach to Optimize Programmed Intermittent Epidural Bolus (PIEB) Delivery for Labour Analgesia

Programmed intermittent epidural bolus (PIEB) for labour analgesia allows an epidural pump to be programmed to deliver small amounts of the local anesthetic and opioid solution at regularly timed intervals. However, little evidence is available to guide optimal settings for PIEB. The gaps in evidence include: (1) programmed timing for the first PIEB bolus (referred to as the "NEXT bolus") (2) determination of PIEB bolus volume (3) the interval for subsequent doses (PIEB interval). Response Surface Methodology will be utilized to best estimate the optimal PIEB settings (NEXT bolus interval, PIEB interval time, PIEB volume) by using the following clinical primary outcome measures: maternal satisfaction score, need for a clinician administered rescue bolus, and the ratio of PCEA boluses requested/delivered.

Inclusion Criteria:

• Nulliparous,
• English speaking
• 18-45 years
• single gestation ≥ 37 weeks
• vertex presentation
• American Society of Anesthesiologists (ASA) Physical Status II (mild and controlled systemic disease and/or pregnancy)
• requesting an epidural for labour analgesia
• cervical dilation ≤ 7 cm at the time of initiation of epidural analgesia.

Exclusion Criteria:

• Preeclampsia or HELLP syndrome
• maternal cardiac disease
• severe or uncontrolled maternal systemic disease
• contraindication to neuraxial analgesia (i.e. coagulopathy, infection, neuropathy)
• abnormal spinal anatomy (i.e. severe scoliosis, spina bifida, spinal instrumentation)
• chronic analgesic use
• a physical or psychiatric condition which may impair cooperation
• known fetal anomalies/intrauterine fetal demise
• height < 5'0"
• Body Mass Index > 45 kg/m2