Optimum Length of Catheter in the Epidural Space for Labor Analgesia in Non-obese Women: a Randomised Controlled Trial of 4 cm Versus 5 cm

Study Overview
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Brief Summary
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Epidural analgesia was introduced to the world of obstetrics in 1909 by Walter Stoeckel. Over the following 100 years it has developed to become the gold-standard for delivery of intra-partum analgesia, with between 60 and 75% of North American parturients receiving an epidural during their labor. Effective labor analgesia has been shown to improve maternal and fetal outcomes. One aspect of catheter insertion that has not been fully evaluated, and with very little recent work undertaken, is the optimal length of epidural catheter to be left in the epidural space. Dislodgement or displacement of epidural catheter remains a significant cause for failure with analgesia. Novel methods of fixation may further reduce the risk of catheter migration. Another factor is the direction of travel within the epidural space, only 13% of lumbar catheters remain uncoiled after insertion of more than 4 cm into the epidural space. Hypothesis: The investigators hypothesize that catheters inserted to 4 cm will have a lower rate of failure when compared to those inserted to 5 cm. Objective: This study aims to evaluate the difference in quality of labor analgesia delivered by epidural catheters inserted to either 4 or 5 cm into the epidural space. This study will be conducted as an interventional double-blinded randomised control trial to establish best practice.

Detailed Description
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Effective labor analgesia has been shown to improve maternal and fetal outcomes. It is of paramount importance to the obstetric anesthesiologist to optimize the quality of labor analgesia and identify any factors leading to ineffective epidural analgesia. One aspect of catheter insertion that has not been fully evaluated, and with very little recent work undertaken, is the optimal length of epidural catheter to be left in the epidural space. Previous studies have advocated, for varying reasons, different lengths of catheter to be left in the space; these range from 2cm to 8cm. Longer epidural lengths in the space can be associated with foraminal escape, leading to unilateral block, and intravascular insertion, prompting additional manipulation. Shorter lengths have previously been associated with more frequent dislodgement. The directionality of the epidural catheter once in the space has been demonstrated to correlate with misdirection. The aim of the study would be to standardize practice in how much epidural catheter is threaded into the epidural space.

Official Title
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Optimum Length of Catheter in the Epidural Space for Labor Analgesia in Non-obese Women: a Randomised Controlled Trial of 4 cm Versus 5 cm

Conditions
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Labor Pain

Intervention / Treatment
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* Other: Epidural catheter


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All women aged 18 years and above. In established second stage of labor. 3-7 cm dilation at time of insertion. Women with BMI < 40 kg/m2 Exclusion Criteria: Known contraindication to epidural insertion. Inability or unwillingness to provide written consent. Previous difficult epidural insertion. Previous failed epidural. Imminent instrumental or operative delivery. Dural puncture. Combined spinal epidural analgesia. High BMI > 40 kg/m2

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 4 cm epidural catheter<br>The epidural catheter will be thread into the epidural space at a length of 4 cm. | Other: Epidural catheter<br>* The epidural catheter length will vary, either 4 cm or 5 cm into the epidural space.<br>* Other names: epidural;|
| Active Comparator: 5 cm epidural catheter<br>The epidural catheter will be thread into the epidural space at a length of 5 cm. | Other: Epidural catheter<br>* The epidural catheter length will vary, either 4 cm or 5 cm into the epidural space.<br>* Other names: epidural;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensory block level < T10 | Sensory block level to ice will be measured 1 hour after the loading dose is administered. Yes: inadequate block No: adequate block | 1 hour | 
| Block height discrepancy | Unilateral block or block height discrepancy of >3 dermatomal levels at any time prior to delivery. Yes: inadequate block No: adequate block | 24 hours | 
| Re-siting of the epidural | Re-siting of the epidural at any time during labour will indicate an inadequate block, for any of the following reasons: Inadequate analgesia Persistent unilateral block Persistent intravascular placement Extensive motor block Hypotension High block | 24 hours | 
| Adjustment of catheter length | Adjustment of catheter length at any time during labour would also indicate an inadequate block. | 24 hours | 
| Abandonment of epidural or substitute for alternative method of analgesia after initial failure: questionnaire | The epidural analgesia will also be considered inadequate if the procedure is abandoned or another method of analgesia is used. This will be recorded by the anesthesiologist. | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain score >3 at any time during labour: questionnaire | A verbal numerical rating score (VNRS) greater than 3, where 0=no pain and 10=worst pain ever. | 24 hours | 
| Number of epidural top-ups administered by the nursing team | The number of times the labour and delivery nurse has to administer a top-up of the epidural. | 24 hours | 
| Number of epidural top-ups administered by the anesthesiologist | The number of times the anesthesiologist has to administer a top-up of the epidural. | 24 hours | 
| Pain scores recorded throughout labour: questionnaire | A verbal numerical rating score (VNRS), where 0=no pain and 10=worst pain ever. A verbal numerical rating score (VNRS) greater than 3, where 0=no pain and 10=worst pain ever. | 24 hours | 
| Hourly sensory block height assessment | Hourly sensory block height assessment, using sensation to ice. This is recorded hourly as standard practice. | 24 hours | 
| Incidence of intravascular epidural placement | Any incidence of intravascular epidural placement during labour will be recorded. | 24 hours | 
| Incidence of catheter dislodgement | Any incidence of catheter dislodgement during labour will be recorded. | 24 hours | 
| Motor block using Bromage scale | Bromage scale will be recorded hourly as standard practice. 3: Unable to move feet or knees 2: Able to move feet only 1: Able to just move knees 0: Full flexion of knees and feet | 24 hours | 
| Presence of paresthesia on insertion. | Any presence of paresthesia on insertion will be recorded. | 1 hour | 
| Adequacy of conversion to surgical block if required for cesarean delivery: questionnaire | Adequacy of conversion to surgical block in cases requiring cesarean deliveries for failed labor or fetal issues. This will be recorded by the anesthesiologist. | 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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epidural catheter, epidural analgesia, labor epidural