Assessment of Sensory Block During Labour Epidural Analgesia in Patients Experiencing Pain During First Stage of Labour.

Assessment of Sensory Block During Labour Epidural Analgesia: a Prospective Cohort Study to Investigate the Upper and Lower Sensory Block Levels (USBL and LSBL) to Ice and Pinprick in Patients Experiencing Pain During First Stage of Labour.

Epidural analgesia is the gold standard for pain control during labour and an essential component of delivering effective and safe epidural analgesia is the assessment of the epidural sensory block. There is significant literature on the assessment of sensory block during spinal anesthesia for cesarean section but limited studies exploring the assessment of sensory blockade in labour analgesia.

Prior studies have documented two thresholds of sensory block to both ice and pinprick: one defined as the lower sensory block level (LSBL) where the patient is able to notice a cold or sharp sensation but perceives that is not as sharp or cold as a control area and the other the upper sensory block level (USBL) where the patient perceives the cold or sharp sensation is at the same temperature or sharpness as the control area.

The goal of this study is to contribute to the standardization of the assessment of sensory block levels during labour epidural analgesia by studying patients with labour epidurals who are experiencing pain and determining the LSBL and USBL and how these change as the patients become comfortable following the administration of manual epidural top ups.

Study Overview

• Status: Completed
• Conditions: Labor Pain

Detailed Description

The pain pathways involved in the process of labour and delivery have been well established. Nociceptive stimuli during first stage of labour are transmitted via the T10 to L1 posterior nerve root ganglia, while the nociceptive stimuli during second stage of labour are transmitted via the L1 and S2 to S4 (pudendal nerve) posterior nerve root ganglia. Although these pain pathways are well established, there is no information in the literature as to what level or depth of sensory block, assessed by current clinical practices, is required for effective labour analgesia. This information is critical for planning and safety of epidural analgesia during labour.

The investigators hypothesize that the LSBL to either cold or pinprick would be below dermatome T10 in patients receiving labour epidural analgesia during first stage of labour and who are experiencing pain. The investigators also hypothesize that upon receiving a top-up and re-establishment of effective analgesia, (a) the LSBL would be at or above dermatome T10 or (b) USBL would increase to T10 or above T10 if USBL was below T10 before receiving a top-up.

• Study Type: Observational
• Enrollment (Actual): 30

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

Patients admitted to the Labor and Delivery unit at Mount Sinai Hospital that receive epidural analgesia for labour and experience pain that is addressed by the anesthesiologist.

Description

Inclusion Criteria:

• ASA (American Society of Anesthesiologists) Physical Status Classification II or III
• Patients admitted to labour and delivery unit at Mount Sinai Hospital in their first stage of labour
• Patients who have a labour epidural that has been initiated as an epidural, CSE (combined spinal epidural) or a dural puncture epidural (DPE).
• Patients who are experiencing pain, defined as Visual Numerical Rating Score of more than 1/10, despite our institution's standard epidural Programmed Intermittent Epidural Bolus maintenance regimen and request a manual epidural top-up for the first time
• Have capacity to consent to the study

Exclusion Criteria:

• Patients with a language barrier that may interfere with accurate response to sensory block assessment
• Patients with medical conditions that would compromise sensitivity to cold or pinprick assessments
• patients who sustained unintentional dural puncture, those requiring change in our standard epidural maintenance regimen or those who have had a failed epidural requiring replacement.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Women with epidural analgesia experiencing pain during labor; Patients reporting pain will have their sensory block checked using ice and pinprick tests, prior to, and following and epidural top-up.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Lower sensory block level to ice when the patient is experiencing pain	The lower sensory block level to ice, defined as the dermatome at which there is a complete loss of cold perception. This will be checked when the patient is experiencing pain and requesting manual administration of an epidural bolus.	5 minutes
Upper sensory block level to ice when the patient is experiencing pain	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 checked when the patient is experiencing pain and requesting manual administration of an epidural bolus.	5 minutes
Lower sensory block level to pinprick when the patient is experiencing pain	The lower sensory block level to pinprick, defined as the dermatome at which there is a complete loss of sharp sensation. This will be checked when the patient is experiencing pain and requesting manual administration of an epidural bolus.	5 minutes
Upper sensory block level to pinprick when the patient is experiencing pain	The upper sensory block level to pinprick is defined as the dermatome at which there is an altered sharp sensation without complete sensitivity loss. This will be checked when the patient is experiencing pain and requesting manual administration of an epidural bolus.	5 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Verbal Numeric Rating Score (VNRS) at the time of request of assessment by anesthesiologist	The patient will be asked to report their VNRS (0-10), where 0 is no pain and 10 is the worst pain imaginable	5 minutes
Verbal Numeric Rating Score (VNRS) at 10 minutes after each epidural top-up administered.	The patient will be asked to report their VNRS (0-10), where 0 is no pain and 10 is the worst pain imaginable, 10 minutes after epidural top-ups are administered.	10 minutes
Motor block score using Bromage score at the time of request of assessment by anesthesiologist	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 checked when the patient is experiencing pain and requesting manual administration of an epidural bolus.	5 minutes
Motor block score using Bromage score following epidural top-up	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 checked 10 minutes following each top-up or when the patient's pain is reported as 0 or 1.	5 minutes
Number of epidural top-ups required	The number of epidural top-ups documented by the anesthesiologist that were required to achieve VNRS of 0 or 1.	20 minutes
Type of pain: questionnaire	Patients will be asked to describe their pain as: sharp/dull/pressure.	20 minutes
Location of pain: questionnaire	Patients will be asked to describe the location of their pain as: abdomen/back/perineum	20 minutes
Lower sensory block level to ice following epidural top-up	The lower sensory block level to ice, defined as the dermatome at which there is a complete loss of cold perception. This will be checked 10 minutes following each top-up or when the patient's pain is reported as 0 or 1.	5 minutes
Upper sensory block level to ice following epidural top-up	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 checked 10 minutes following each top-up or when the patient's pain is reported as 0 or 1.	5 minutes
Lower sensory block level to pinprick following epidural top-up	The lower sensory block level to pinprick, defined as the dermatome at which there is a complete loss of sharp sensation. This will be checked 10 minutes following each top-up or when the patient's pain is reported as 0 or 1.	5 minutes
Upper sensory block level to pinprick following epidural top-up	The upper sensory block level to pinprick is defined as the dermatome at which there is an altered sharp sensation without complete sensitivity loss. This will be checked 10 minutes following each top-up or when the patient's pain is reported as 0 or 1.	5 minutes

Collaborators and Investigators

• Sponsor: Samuel Lunenfeld Research Institute, Mount Sinai Hospital
• Investigators: Principal Investigator: Jose Carvalho, MD, Mount Sinai Hospital

Study record dates

Study Major Dates

• Study Start (Actual): June 16, 2023
• Primary Completion (Actual): December 2, 2023
• Study Completion (Actual): December 3, 2023

Study Registration Dates

• First Submitted: May 19, 2023
• First Submitted That Met QC Criteria: May 19, 2023
• First Posted (Actual): May 31, 2023

Study Record Updates

• Last Update Posted (Actual): February 23, 2024
• Last Update Submitted That Met QC Criteria: February 22, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Keywords: epidural analgesia; programmed intermittent epidural bolus; sensory block
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Labor Pain
• Other Study ID Numbers: 23-01

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