Last updated on May 2018

Buffered Lidocaine in Paracervical Blocks

Brief description of study

For pain relief during a first trimester surgical aspiration, most providers use the paracervical block, either alone or in combination with other pain control techniques. Some providers use buffered lidocaine due to a belief that it decreases pain. Others use plain lidocaine. At our clinics, the standard pain management protocol is using 20 cc of 1% plain lidocaine in a two site injection. Few studies have compared buffered versus unbuffered lidocaine for paracervical blocks during first trimester uterine aspirations. This study seeks to determine if buffered lidocaine decreases injection pain versus plain lidocaine for paracervical blocks.

Detailed Study Description

Potential participants will be identified at their office visits to the University Women's Health Specialists. If a patient desires uterine aspiration of a first trimester pregnancy or management of a failed pregnancy in the first trimester, they will first receive standard counseling. Only after providing written informed consent for the procedure will the patient's be screened for eligibility for our study. If the patient is eligible, she will be asked by a member of the research team if she is interested in participating. If she is, the study will be explained to her and written consent will be obtained after she is given the opportunity to have all of her questions answered. The patient will then complete a written questionnaire to collect demographic data.

This prospective randomized control trial will consist of two study arms. Participants will be randomly assigned to Arm 1, where a paracervical block will be administered with 20 cc of 1% lidocaine, which is our standard office protocol, or to Arm 2, where a paracervical block will be administered with 20 cc of 1% lidocaine buffered with 8.4% sodium bicarbonate. Prior to the start of the study, study assignments will be generated in a 1:1 ratio.

All patients who consent to the study will receive standard counseling prior to their procedure. The procedure will start with a bimanual exam by the provider. Next, the provider will place a speculum, cleanse the cervix with betadine solution, and place a single-tooth tenaculum on the anterior lip of the cervix. At this point, participants assigned to Arm 1 will receive a paracervical block loaded with 20 cc of 1% lidocaine and injected at 2, 4, 8 and 10 o'clock positions of the cervicovaginal junction. Participants assigned to Arm 2 will receive a paracervical block loaded with 18 cc of 1% lidocaine and 2 cc of 8.4% sodium bicarbonate and inject the block in the same fashion. The research assistant will ask the patient to verbally report their level of pain based on the 100 mm visual analog scale (VAS) at the following points of the procedure:

  1. Prior to the start of the procedure (baseline anxiety)
  2. After speculum placement
  3. After paracervical block
  4. After cervical dilation
  5. After suction curettage
  6. At end of procedure

Clinical Study Identifier: NCT03107754

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