Influence of Lumbar Ultrasound on Resident Learning Curve for Lateral Labor Epidural Placement

Study Overview
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Brief Summary
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The aim of this study is to evaluate the impact of lumbar spine ultrasound on the success rate and efficiency of labor epidural placement in the lateral position. The investigators hypothesize that ultrasound imaging of the lumbar spine of women in early labor will yield similar ultrasound results when done immediately prior to epidural placement. The investigators also hypothesize that the use of ultrasound with landmarks marked and depth to the epidural space estimated will facilitate epidural placement in terms of both efficiency (time required for placement) and efficacy of pain relief.

Detailed Description
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Several studies have demonstrated a significant benefit in pre-procedural ultrasound for epidural placement by anesthesia residents, particularly when performed in the obese population. To the investigators knowledge, however, no studies have evaluated this teaching modality for the lumber epidural technique in the lateral position. Formalizing the educational process for this less frequently performed, highly technical and critical skill may have a profound impact on trainee learning curves, and may enhance the overall success and efficiency of epidural placement, quality of analgesia provided, and safety of the procedure.

Official Title
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Pre-insertion Ultrasound Guidance for Labor Epidural Placement in the Lateral Position: A Randomized Controlled Trial of Image Reproducibility During Labor and Impact on Resident Learning Curve

Conditions
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Labor Epidural, Lumbar Ultrasound

Intervention / Treatment
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* Other: Ultrasound


Participation Criteria
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Eligibility Criteria
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Pregnant Subjects Inclusion Criteria: pregnant women 18 years or older in early labor (cervix dilated < 5 cm pain visual analog score (VAS) < 3, or both) requesting consultation by the anesthesia team for anticipated epidural pain relief. Exclusion Criteria: absolute contraindications of neuraxial anesthesia including patient refusal uncorrected coagulopathy infection at the skin site of epidural placement increased intracranial pressure, or untreated hemodynamic instability. In addition, patients with a history of scoliosis or spine surgery body mass index (BMI) >40 kg/m2 allergy to local anesthetic, or allergy to opioids will be excluded. Anesthesiologists Inclusion criteria: Anesthesia residents or fellows who are performing the epidural technique in pregnant subjects who agree to be part of the study. Anesthesia residents or fellows with prior experience in the lumbar epidural technique, defined as having placed 20 or greater lumbar epidurals during their residency and prior to enrollment. Exclusion criteria: individuals who do not want to participate in the study.

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control<br>Baseline ultrasound only, with no markings placed. No ultrasound prior to epidural placement. | |
| Experimental: Ultrasound<br>Baseline and pre-puncture ultrasound with markings placed. | Other: Ultrasound<br>* A baseline lumbar ultrasound in a standardized lateral position (by bed markings) will be performed with the midline and L3-L4 interspace marked, and estimated depth to the epidural space recorded. A second lateral lumbar ultrasound will be performed immediately prior to placement at the time of epidural request. The bed position will be standardized with lines drawn down the back, at the flexion of the knee, and heel of the foot. The sonographic measurements will include the midline, the L3-4 interspace, (both marked at the skin surface), and the measured depth to the ligamentum flavum (in centimeters).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Depth to the epidural space (cm) from baseline ultrasound compared to pre-placement ultrasound. | Measured depth to the epidural space (cm) from baseline ultrasound compared to pre-placement ultrasound, measured with a 2-5 MHz curvilinear ultrasound probe at the lumbar spine, midline, at level L3-4. | From enrollment to time of epidural placement, approximately 5 hours | 
| Time required for epidural placement | Time required for placement (T0 = insertion of needle for subcutaneous lidocaine infusion prior to epidural needle placement). Tfinal = time at complete removal of Weiss epidural needle after catheter is threaded into the epidural space. | From enrollment to time of epidural placement, approximately 5 hours | 
| Need for assistance from additional anesthesiologist | Need for assistance from additional anesthesiologist | From enrollment to time of epidural placement, approximately 5 hours | 
| Number of attempts at epidural placement | defined as number of times the Weiss epidural needle enters the skin | From enrollment to time of epidural placement, approximately 5 hours | 
| Incidence of paresthesias | Paresthesia defined as pain with needle or catheter insertion | From enrollment to time of epidural placement, approximately 5 hours | 
| Labor pain at time of 30 minutes after placement is complete. | Labor pain rated on a visual analog scale (VAS) | From enrollment to time of epidural placement, approximately 5 hours, plus 30 minutes. | 
| Rate of epidural replacement for inadequate analgesia | Inadequate analgesia determined as VAS >3 despite catheter adjustment and/or epidural dose adjustment. | From enrollment to time of epidural placement, approximately 5 hours | 
| Rate of inadvertent dural puncture at the time of placement. | Defined as cerebrospinal fluid aspiration through needle or catheter. | From enrollment to time of epidural placement, approximately 5 hours | 
| Midline measurement from baseline ultrasound compared to pre-placement ultrasound. | Measured midline (anatomical marking) from baseline ultrasound compared to pre-placement ultrasound, measured with a 2-5 MHz curvilinear ultrasound probe at the lumbar spine, midline. | From enrollment to time of epidural placement, approximately 5 hours | 
| L3-L4 lumbar spine level measured from baseline ultrasound compared to pre-placement ultrasound. | Measured L3-L4 lumbar spine level from baseline ultrasound compared to pre-placement ultrasound, measured with a 2-5 MHz curvilinear ultrasound probe at the lumbar spine, paramedic. | From enrollment to time of epidural placement, approximately 5 hours |