Changes in Sensory Block Level During a Programmed Intermittent Epidural Bolus Regimen for Labor Analgesia: an Observational Cohort Study

Epidural analgesia is widely used for managing pain during labor. The programmed intermittent epidural bolus (PIEB) technique has been shown to produce less consumption of local anesthetics, better sensory block, less motor block, and increased maternal satisfaction than other epidural analgesia techniques. Despite all benefits from PIEB, such practice has been associated with high sensory block levels. Therefore, assessment of the sensory block level is an essential component of clinical safety. The lack of a standardized technique and timing to assess the sensory block level can lead to inappropriate management. The purpose of this study is to investigate the changes in block level over time, during cycles of a PIEB regimen. The investigators hypothesize that these levels will be highest soon after the PIEB bolus and lowest preceding the subsequent PIEB bolus. The investigators also want to investigate a possible correlation between these changes in sensory block levels and motor block, pain scores, and rescue bolus of local anesthetics.

Study Overview

• Status: Completed
• Conditions: Labor Pain
• Intervention / Treatment: Other: Sensory block level check

• Study Type: Observational
• Enrollment (Actual): 34

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5G1X5
      • Mount Sinai Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: N/A
• Genders Eligible for Study: Female

• Sampling Method: Non-Probability Sample

Study Population

Women admitted to the Labor and Delivery unit at Mount Sinai Hospital that request to receive epidural analgesia.

Description

Inclusion Criteria:

• women admitted to the Labor and Delivery unit at Mount Sinai Hospital that request and have no contraindications to receive epidural analgesia
• 18 years old or more
• capable of understanding and signing the written informed consent
• have no language barrier to respond to the level of sensory block assessment
• and have no conditions that could compromise the body sensitivity to cold.

Exclusion Criteria:

• unintentional dural puncture during labour epidural placement
• do not achieve adequate pain control 20 minutes after the loading dose (numeric rating scale (NRS)>1 on a 0-10 NRS),
• deliver before 160 minutes following the loading dose
• require rescue boluses in the first 80 minutes after initiation of PIEB (that is, before the 2nd PIEB bolus)
• withdraw their consent.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Women receiving epidural analgesia for labor	Other: Sensory block level check; Patients will have their sensory block level checked multiple times following administration of their epidural bolus for labor analgesia.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Lower sensory block level over time	The lower sensory block level to ice, defined as the dermatome at which there is a complete loss of cold perception. This will be measured at 20, 60, 80, 90, 100, 110, 120, 130, 140, 150, and 160 minutes post-loading dose of epidural medication.	20 to 160 minutes post-loading dose
Change in Upper sensory block level over time	The upper sensory block level to ice is defined as the dermatome at which there is an altered cold perception without complete sensitivity loss. This will be measured at 20, 60, 80, 90, 100, 110, 120, 130, 140, 150, and 160 minutes post-loading dose of epidural medication.	20 to 160 minutes post-loading dose

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Motor block score using Bromage score	Motor block will be assessed with the Bromage score: 0 = able to raise the extended leg; 1 = unable to raise the extended leg but able to flex knees; 2 = unable to flex knees, but able to flex ankle; 3 = unable to flex ankle. This will be measured at 20, 60, 80, 90, 100, 110, 120, 130, 140, 150, and 160 minutes post-loading dose of epidural medication.	20 to 160 minutes post-loading dose
Pain score	Pain score using verbal numerical rating scale (VNRS) (0-10, where 0=no pain and 10=worst pain ever). This will be measured at 20, 60, 80, 90, 100, 110, 120, 130, 140, 150, and 160 minutes post-loading dose of epidural medication.	20 to 160 minutes post-loading dose
Additional analgesia administered	Use and timing of use of PCEA and/or manual bolus will be recorded if they are administered at any time during the study time period.	160 minutes

Collaborators and Investigators

• Sponsor: Samuel Lunenfeld Research Institute, Mount Sinai Hospital

Publications and helpful links

General Publications

• Casellato JF, Ye XY, Downey K, Carvalho JCA. Changes in sensory block level during a programmed intermittent epidural bolus regimen for labour analgesia: a prospective observational cohort study. Can J Anaesth. 2022 Dec;69(12):1471-1476. doi: 10.1007/s12630-022-02318-w. Epub 2022 Sep 8.

Study record dates

Study Major Dates

• Study Start (Actual): February 2, 2021
• Primary Completion (Actual): August 9, 2021
• Study Completion (Actual): August 9, 2021

Study Registration Dates

• First Submitted: January 12, 2021
• First Submitted That Met QC Criteria: January 18, 2021
• First Posted (Actual): January 20, 2021

Study Record Updates

• Last Update Posted (Actual): September 21, 2021
• Last Update Submitted That Met QC Criteria: September 20, 2021
• Last Verified: September 1, 2021

More Information

Terms related to this study

• Keywords: epidural analgesia; labor epidural; programmed intermittent epidural bolus; sensory block
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Labor Pain
• Other Study ID Numbers: 21-01

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