Efficacy and Safety of Electric Stimulation-guided Epidural Anesthesia for Cesarean Section

Study Overview
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Brief Summary
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Forty pregnant women (36 to 41 weeks gestation) will randomly allocate to two groups. Groups will be defined based on the method used to identify the epidural space for epidural anesthesia: the loss of resistance group (n=20) and the epidural electric stimulation group (n=20). Pain during the cesarean section will be assessed using a numerical visual analog scale and maternal satisfaction by a post-partum interview. The success rate of epidural anesthesia, maternal satisfaction, and neonatal Apgar scores will be compared between groups.

Detailed Description
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Investigators will place epidural catheter in the epidural space using loss of resistance technique, and will confirm correct placement of the epidural catheter using electric stimulation. Epidural catheter placement, electric stimulation, and confirmation of response is followed: Patients will be placed in the left lateral decubitus position. The site will be aseptically prepared and 1% lidocaine will be infiltrated to the skin. An 18-gauge Tuohy needle will be inserted midline of L4/5 interspinous space. For the LOR group, after identification of the epidural space, the Tuohy needle will be stopped, and a 20-gauge epidural catheter will be advanced through the Touhy needle. The same process will be followed for the EES group. In addition, the epidural space will be confirmed by epidural electric stimulation using a 20-gauge epidural catheter (RegionalStimTm, Sewoon Medical Co., Ltd, Seoul, Korea, 800 mm) with a conductive guidewire (conductive guidewire, Nitinol, 1100 mm). After confirming there is no reverse flow of cerebrospinal fluid or blood with aspiration, 3 mL of 1% lidocaine, with 15 mcg of epinephrine (1:200000), will be injected through the epidural catheter as test dose. If there is no response to the test dose, patients will be moved to the operating room. In operating room, 20 mL of 2% lidocaine, 2 mL of bicarbonate (total volume 22 mL) will be administered in divided doses. Blood pressure (BP), heart rate (HR), oxygen saturation (SpO2), and neurologic assessment findings will be monitored. Pain relief in cesarean section is assessed in the visual analogue scale (VAS) score. A 10 point VAS, where 0 is no pain and 10 is unbearable pain, is used to assess pain during labor. The scale is assessed after epidural anesthesia. Differences in the VAS we used to assess the efficacy of the epidural anesthesia in decreasing labor pain. Comparison of the change in VAS between groups is used to compare pain control of the two methods. The success of epidural anesthesia is defined by sensory block, without motor block, and a decrease in pain score after adequate dosing of epidural medication. Failure of epidural anesthesia is defined in several ways. Objective outcome include conversion to general anesthesia, conversion to any different form of anesthesia, or pain during surgery. Patient satisfaction will be evaluated by a postpartum interview. Satisfaction is graded between a score of 1-5, where 1 represent very unsatisfied and 5 represent very satisfied. Patients will indicate a score of 1 to 5. One- and 5-minute Apgar scores will be compared to assess the effect of epidural electric stimulation on the neonate. Additional time required for epidural electric stimulation will be determined by the difference (in seconds) from LOR to identification of the epidural space through electric stimulation.

Official Title
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A Comparative Study of Success Rate, Efficacy, Safety Between Electric Stimulation-guided Epidural Catheter Placement and the Loss of Resistance Conventional Method for Cesarean Section

Conditions
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Epidural Anesthesia

Intervention / Treatment
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* Device: Epidural electrical stimulation (EES)
* Device: Loss of resistance (LOR)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who were at 36 to 41 weeks' gestation and admitted in labor to the university clinic for cesarean section were included. Patients were American Society of Anesthesiologists (ASA) physical status of I or II, and were scheduled to receive epidural anesthesia. Exclusion Criteria: Skin infection at the injection site Difficult catheter placement owing to previous lumbar spinal surgery or deformity Presence of a hemostatic disorder or use of antiplatelet therapy Presence of a cardiac pacemaker. Removal of patient

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 64 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Epidural electrical stimulation (EES)<br>n=20 | Device: Epidural electrical stimulation (EES)<br>* Using loss of resistance technique and electrical stimulation<br>|
| Active Comparator: Loss of resistance (LOR)<br>n=20 | Device: Loss of resistance (LOR)<br>* Using loss of resistance technique only<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Success rate of epidural anesthesia | Evaluation parameter : Accuracy comparison between loss of resistance and epidural electrical stimulation | Up to 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maternal satisfaction | Patient satisfaction will be evaluated by a postpartum interview. Satisfaction was graded by patients from 1 to 5, where 1 represented very unsatisfied and 5 represented very satisfied | Up to 6 months | 
| Neonatal Apgar score | The neonatal apgar scores from 0 to 10 were measured at 1 and 5 minutes to assess the effect of electrical stimulation on the fetus; Scores 7 and above are generally normal, 4 to 6 fairly low, and 3 and below are generally regarded as critically low | Up to 6 months | 
| Procedure-related complications | The number of times dural puncture or intravascular insertion was performed by Tuohy needle of epidural catheter during epidural anesthesia | Up to 6 months | 
| Minimum electrical current to elicit a response in the epidural electrical stimulation group | Minimum current stimulus to confirm that the epidural catheter is located in the epidural space between 0 and 5mA ;mA (frequency, 1 Hz; pulse width, 300 ms) | Up to 6 months | 
| Additional time for epidural electrical stimulation | Determined by the difference (in seconds) from loss of resistance(LOR) to identification of the epidural space through electrical stimulation Measure : seconds (from observation of LOR to confirmation of the epidural space by electric stimulation) | Up to 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Electric stimulation, Cesarean section