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NCT Number: NCT05881395

Assessment of Sensory Block During Labour Epidural Analgesia 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.

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Key information

Conditions

Labor Pain Neurologic Manifestations Pain Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–50 year

Sex eligibility

Female

Study type

Observational

Primary location

Mount Sinai Hospital

Toronto, Ontario, M5G1X5, Canada

About this study

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.

Who can participate

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Primary outcomes

  1. Lower sensory block level to ice when the patient is experiencing pain

    Time frame: 5 minutes

    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.

  2. Upper sensory block level to ice when the patient is experiencing pain

    Time frame: 5 minutes

    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.

  3. Lower sensory block level to pinprick when the patient is experiencing pain

    Time frame: 5 minutes

    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.

  4. Upper sensory block level to pinprick when the patient is experiencing pain

    Time frame: 5 minutes

    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.

Secondary outcomes

  1. Verbal Numeric Rating Score (VNRS) at the time of request of assessment by anesthesiologist

    Time frame: 5 minutes

    The patient will be asked to report their VNRS (0-10), where 0 is no pain and 10 is the worst pain imaginable

  2. Verbal Numeric Rating Score (VNRS) at 10 minutes after each epidural top-up administered.

    Time frame: 10 minutes

    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.

  3. Lower sensory block level to ice following epidural top-up

    Time frame: 5 minutes

    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.

  4. Upper sensory block level to ice following epidural top-up

    Time frame: 5 minutes

    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. Lower sensory block level to pinprick following epidural top-up

    Time frame: 5 minutes

    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.

  6. Upper sensory block level to pinprick following epidural top-up

    Time frame: 5 minutes

    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.

  7. Motor block score using Bromage score at the time of request of assessment by anesthesiologist

    Time frame: 5 minutes

    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.

  8. Motor block score using Bromage score following epidural top-up

    Time frame: 5 minutes

    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.

  9. Number of epidural top-ups required

    Time frame: 20 minutes

    The number of epidural top-ups documented by the anesthesiologist that were required to achieve VNRS of 0 or 1.

  10. Type of pain: questionnaire

    Time frame: 20 minutes

    Patients will be asked to describe their pain as: sharp/dull/pressure.

  11. Location of pain: questionnaire

    Time frame: 20 minutes

    Patients will be asked to describe the location of their pain as: abdomen/back/perineum

Sponsors and collaborators

Lead sponsor

Samuel Lunenfeld Research Institute, Mount Sinai Hospital

Other

Registry information

Official study title

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.

Important dates

Study start
2023
Primary completion
2023
Study completion
2023
First posted
May 31, 2023
Registry last updated
Feb 23, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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