ED50 and ED95 of Isobaric Bupivacaine for Post-Partum Bilateral Tubal Ligation

Determination of ED50 and ED95 of Isobaric Bupivacaine for Post-Partum Bilateral Tubal Ligation

Spinal anesthesia is one of the preferred anesthetic techniques for post-partum bilateral tubal ligation (PBTL). Bupivacaine is the most commonly used local anesthetic for neuraxial anesthesia for post-partum tubal ligation. Typically, hyperbaric bupivacaine would be injected into the spinal (intrathecal) space via a spinal needle; however, ongoing medication shortages have resulted in limited availability on a local and national level. One proposed alternative is isobaric bupivacaine; however, studies investigating its use for post-partum bilateral tubal ligation are limited.

The purpose of this prospective study is to determine the minimal effective dose (ED50 and ED95) of isobaric bupivacaine for adequate anesthesia during post-partum tubal ligation after vaginal delivery.

Study Overview

• Status: Completed
• Conditions: Anesthesia, Local
• Intervention / Treatment: Other: Dose adjustment of bupivacaine

Detailed Description

This prospective study proposes to enroll 40 post-partum women who are undergoing elective post-partum bilateral tubal ligation. The patient will be positioned sitting, and combined spinal anesthesia will be performed at L2-3 or L3-4 level. The presence of an epidural catheter enables the provider to supplement the spinal anesthetic if required. The starting dose of isobaric bupivacaine will be 10 mg based on prior similar studies1,4 and our institution's current practice. The dose of intrathecal isobaric bupivacaine was decided by using the up-down sequential method.

The motor block will be graded by a modified Bromage score: Score 1 = complete block, unable to move feet or knees; 2 = almost complete block, able to move feet only; 3 = partial block, just able to move knees; 4 = detectable weakness of hip flexion while supine, full flexion of knees; 5 = no detectable weakness of hip flexion while supine; and 6 = able to perform partial knee bend. The score of 1 or 2 within 10-15 minutes of injection will be evaluated as successful motor block.

The success of the sensory spinal block will be noted when bilateral T6 sensory level to pinprick is attained after 10 mins from the intrathecal drug administration, this is in accordance with previous studies1.

If spinal anesthesia is inadequate, the epidural catheter will be dosed up for supplementation. All observations, including block characteristics and the associated outcome (i.e., adequate or inadequate block), will be evaluated by a dedicated anesthesia provider.

Intraoperative adverse effects, such as hypotension, bradycardia, nausea, or vomiting, pruritus, or shivering were noted. Hypotension is defined as a decrease of more than 20% in basal systolic blood pressure within 30 minutes of intrathecal injection. The management of blood pressure including dose of pressor: phenylephrine and ephedrine will be at the discretion of the attending anesthesiologist. The use of pressor and anti-emetics will also be recorded.

The study will be take place in standard clinical context. The study does not deviate from our current practice, which includes the use of combined spinal anesthesia where the epidural catheter is available if supplemental local anesthetic is required.

• Study Type: Interventional
• Enrollment (Actual): 33
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Dallas, Texas, United States, 75235
      • Parkland Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• Age 18 and older
• Patients undergoing elective post-partum bilateral tubal ligation after vaginal delivery
• Patients receiving spinal epidural anesthesia with combination of bupivacaine and fentanyl

Exclusion Criteria:

• American Society of Anesthesiologists physical status score >3,
• Contraindications to neuraxial analgesia
• Patients in whom a combined spinal epidural cannot be performed
• Body mass index >40 kg/m2
• Allergy or hypersensitivity to local anesthetics and fentanyl
• Severe liver, kidney or respiratory disease.
• Inability to understand the study protocol
• Refusal to provide written consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Dose adjustment of bupivacaine; Patient will receive isobaric bupivacaine based on previous patient experience.	Other: Dose adjustment of bupivacaine; Spinal bupivacaine dose will be adjusted according to previous patient experience.; Other Names: Spinal bupivacaine dose adjustment

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Success or failure of the intrathecal block	The score of 1 or 2 within 10-15 minutes of injection will be evaluated as successful motor block.	Perioperative

Collaborators and Investigators

• Sponsor: University of Texas Southwestern Medical Center
• Investigators: Study Chair: Seema Dave, MPH, UT Southwestern Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): February 25, 2019
• Primary Completion (Actual): June 17, 2019
• Study Completion (Actual): April 9, 2020

Study Registration Dates

• First Submitted: December 17, 2018
• First Submitted That Met QC Criteria: December 17, 2018
• First Posted (Actual): December 19, 2018

Study Record Updates

• Last Update Posted (Actual): May 19, 2020
• Last Update Submitted That Met QC Criteria: May 15, 2020
• Last Verified: May 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Sensory System Agents; Anesthetics; Anesthetics, Local; Bupivacaine
• Other Study ID Numbers: STU 082018-026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No