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

Study Overview
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Brief Summary
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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.

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

Conditions
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Labor Pain

Intervention / Treatment
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* Other: Sensory block level check


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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Female

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Women receiving epidural analgesia for labor<br> | Other: Sensory block level check<br>* Patients will have their sensory block level checked multiple times following administration of their epidural bolus for labor analgesia.<br>|

What is the study measuring?
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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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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programmed intermittent epidural bolus, epidural analgesia, labor epidural, sensory block