Effects of Bupivacaine Induced Motor Blockade During the Second Stage of Labor
Condition: Pregnancy
Intervention: Epidural Bupivacaine plus fentanyl; Epidural fentanyl
Intervention description: The subjects will receive 0.125% bupivacaine with fentanyl 2 mcg/mL at a rate of 10 mL/hr.; The subjects will receive epidural fentanyl 10 mcg/mL with the rate of 10mL/hr.
Intervention MeSH terms: Fentanyl; Bupivacaine
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: double-blinded 2 arm
Masking: Double (Participant, Investigator)
Enrollment: 481.0
Sex: Female
Minimum age: 16 Years
Maximum age: 44 Years
Healthy volunteers: Accepts Healthy Volunteers
Keywords: Bupivacaine; Fentanyl; Epidural; Second Stage of Labor; Randomized Controlled Trial

Summary:

      The aim of this study is to measure the effects of bupivacaine administered via epidural
      catheters on indices of motor blockade ascertained during the second stage of labor. This is
      a randomized, double-blind, controlled trial designed to address the primary research
      question: Does bupivacaine lengthen the second stage of labor? The secondary research
      question is: Is there other evidence of motor blockade attributable to bupivacaine during the
      second stage of labor?

      The investigators know from prior studies that the length of the second stage in nulliparous
      women delivered at Parkland Hospital without epidural analgesia is 28 minutes. The
      investigators hypothesize in this now proposed study that epidural analgesia with bupivacaine
      will significantly increase this baseline from 28 minutes to 37 minutes or more (a 33%
      increase) thus implicating motor blockade. Baseline data for the Bromage and Breen scores
      during the second stage as well as the uterine contractility data are not available as these
      indices of motor blockade have not here-to-fore been studied in this context.

      Currently at Parkland Hospital, 82% of nulliparous women undergoing induction of labor at
      term receive continuous epidural infusions with bupivacaine during the first and second
      stages of labor. Such women will be identified when admitted for scheduled inductions at
      Parkland. After informed consent is obtained standard management of labor induction will be
      provided. Those consented women reaching 8 cm cervical dilation will be randomized. Group I
      will receive bupivacaine plus fentanyl via epidural catheter during the second stage (i.e. 10
      cm dilation) and Group II will receive only fentanyl infusion via epidural catheter (see
      study procedure below). Both the patient and the caregiver will be blinded as to whether the
      patient is in the bupivacaine plus fentanyl arm or the fentanyl only arm. To detect a 33%
      increase (from 28 minutes to 37 minutes) in the primary outcome the investigators need a
      total of 310 women enrolled in the study (or 155 per arm). Assuming a 30% consent rate and
      given that approximately 1000 women meet the inclusion criteria each year at Parkland, the
      investigators project that this study could be completed in 12 months.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Nulliparous women at 37 weeks gestation or greater.

          -  Scheduled for induction of labor for any indication, to include hypertensive
             disorders, diabetes, decreased fetal motion, or prolonged pregnancy.

          -  Single without known malformations.

          -  Maternal age > or equal to 16 years.

          -  ASA classification 1 or 2.

        Exclusion Criteria:

          -  Women who refuse epidural analgesia.

          -  Women with contraindications to epidural analgesia, i.e., severe thrombocytopenia.

          -  Any renal disease with serum creatinine > 1.0 mg/dL.

          -  Allergy to bupivacaine or fentanyl.

          -  Known liver disease such as hepatitis.

          -  Known contraindications to internal electronic fetal monitoring i.e., active herpes,
             maternal HIV seropositivity.