Reliability of Waveform Analysis as an Adjunct to Loss of Resistance for Obstetrical Epidural Blocks

Study Overview
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Brief Summary
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In this study, we will set out to confirm the reliability of epidural waveform analysis (EWA) as an adjunct to loss of resistance for obstetrical epidural blocks.

Detailed Description
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After loss of resistance, 5 mL of normal saline will be injected through the epidural needle; the latter will then be connected to a pressure transducer (leveled with the heart) using a rigid tubing. A pressure recording of the epidural waveform will be saved for future assessment by a blinded observer. After the recording of the waveform, the rigid tubing will be disconnected from the epidural needle. A 4 mL bolus of lidocaine 2% with epinephrine 5 µg/mL will be injected through the latter. An epidural catheter will be advanced 3-4 cm past the tip of the needle inside the epidural space. The needle will then be removed and the catheter secured to the skin in the usual fashion. Fifteen minutes after the injection of the local anesthetic bolus, a blinded observer will apply ice to the T1-L5 dermatomes and assess the epidural block.

Official Title
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Reliability of Waveform Analysis as an Adjunct to Loss of Resistance for Obstetrical Epidural Blocks

Conditions
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Pregnancy

Intervention / Treatment
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* Other: Obstetrical patients


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: -American Society of Anesthesiologists classification 1-3 Exclusion Criteria: adults who are unable to give their own consent coagulopathy (assessed by history and physical examination and, if deemed clinically necessary, by blood work up ie platelets ≤ 100, International Normalized Ratio ≥ 1.4 or prothrombin time ≥ 50) renal failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up ie creatinine ≥ 100) hepatic failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up ie transaminases ≥ 100) allergy to local anesthetic prior surgery in the lumbar spine

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Obstetrical patients<br>Obstetrical patients requiring epidural analgesia for delivery | Other: Obstetrical patients<br>* Epidural waveform analysis as a confirmation of loss of Resistance<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Success rate | Success rate evaluated with sensory block to ice | 15 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Epidural waveform analysis | presence or absence of an epidural waveform measured through the epidural catheter right after insertion | Immediately after epidural catheter insertion |