Epidural Waveform Analysis for Thoracic Epidural Blocks

Study Overview
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Brief Summary
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Epidural waveform analysis (EWA) provides a simple confirmatory adjunct for loss-of-resistance (LOR): when the needle/catheter tip is correctly positioned inside the epidural space, pressure measurement results in a pulsatile waveform. Epidural waveform analysis can be carried out through the tip of the needle or the catheter. In this randomized trial, the objective is to compare epidural waveform analysis through the needle (EWA-N) and through the catheter (EWA-C) for thoracic epidural blocks.

Detailed Description
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The epidural space is most commonly identified with loss-of-resistance (LOR). Though sensitive Epidural waveform analysis (EWA) provides a simple confirmatory adjunct for LOR. When the needle (or catheter) is correctly positioned inside the epidural space, pressure measurement at its tip results in a pulsatile waveform synchronized with arterial pulsations Currently, there exist two different methods for EWA. Since local anesthetic (LA) is administered through the catheter, pressure transduction through its tip ensures that it is properly positioned inside the epidural space prior to LA injection. Alternately, EWA can be performed through the needle prior to blind advancement of the epidural catheter. Thus, in this randomized trial, the aim is to compare epidural waveform analysis through the needle (EWA-N) and through the catheter (EWA-C) for thoracic epidural blocks. The hypothesis is that, compared to EWA-C, EWA-N will result in a shorter performance time.

Official Title
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A Randomized Comparison Between Epidural Waveform Analysis Through the Needle Versus the Catheter for Thoracic Epidural Blocks

Conditions
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Surgical Procedure, Unspecified

Intervention / Treatment
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* Device: EWA through the needle
* Device: EWA through the catheter


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age between 18 and 80 years American Society of Anesthesiologists classification 1-3 body mass index between 20 and 35 Exclusion Criteria: adults who are unable to give their own consent coagulopathy renal failure hepatic failure allergy to local anesthetic pregnancy prior surgery in the thoracic spine

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

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
Interventional Model Description: Randomized trial
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: EWA through the needle<br>EWA through the needle group, 5 mL of normal saline are injected through the epidural needle after the occurrence of LOR. The needle is subsequently connected to the pressure transducer (leveled with the heart) via the sterile, rigid extension tubing. A satisfactory endpoint is defined as the presence of waveforms synchronized with arterial pulsations. | Device: EWA through the needle<br>* In the EWA-N group, 5 mL of normal saline are injected through the epidural needle after the occurrence of loss-of-resistance (LOR). The needle is connected to the pressure transducer. A satisfactory endpoint is defined as the presence of waveforms synchronized with arterial pulsations. In the absence of pulsatile waveforms, the operator injects an additional 2.5 mL-bolus of normal saline through the epidural needle and reconnects the latter to the pressure transducer. If no waveforms are detected after the second injection, the operator removes the needle and reattempts the epidural block at a different intervertebral level. A maximum of 3 levels is permitted: if waveforms are still absent at the third level, the operator simply accepts LOR as the technical endpoint.<br>|
| Experimental: EWA through the catheter<br>EWA through the catheter group, the epidural catheter is advanced 5 cm beyond the needle tip after the occurrence of LOR. Subsequently, the operator injects 5 mL of normal saline through the catheter and the latter is connected to the pressure transducer via the sterile, rigid extension tubing. A satisfactory endpoint is defined as the presence of waveforms synchronized with arterial pulsations. | Device: EWA through the catheter<br>* In the EWA-C group, the epidural catheter is advanced 5 cm beyond the needle tip after the occurrence of LOR. Subsequently, the operator injects 5 mL of normal saline through the catheter and the latter is connected to the pressure transducer via the sterile, rigid extension tubing. A satisfactory endpoint is defined as the presence of waveforms. In the absence of pulsatile waveforms, the operator injects an additional 2.5 mL-bolus of saline through the catheter and reconnects the latter to the pressure transducer. If no waveforms are detected after the second injection are still absent at the third level, the operator simply accepts this position for catheter placement (intent-to-treat analysis).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Performance time of block | temporal interval in minutes between skin infiltration and local anesthetic administration through the epidural catheter (after obtaining a satisfactory waveform either through the needle or through the catheter depending on randomized group assignment). | From skin infiltration until local anesthetic administration through the needle or catheter, up to 60 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of successful epidural block | bilateral block to ice in at least 2 dermatomes | 15 minutes after the administration of local anesthetic through the epidural catheter | 
| Procedural pain during epidural block assessed by the numeric rating scale | pain in the back of the patient, related to the performance of the epidural block, using a numeric rating scale from 0 to 10 points (0=no pain and 10= worst imaginable pain) | From the performance of the epidural block until induction of general anesthesia, up to 2 hours | 
| Postoperative pain related to surgical incision assessed by the numeric rating scale | pain at rest and upon deep breathing/coughing, measured using a numeric rating scale from 0 to 10 points ((0=no pain and 10= worst imaginable pain) | twice a day from the arrival at PACU or until catheter removal, up to 5 days | 
| Local anesthetic consumption | amount of local anesthetic consumed | once a day from the arrival at PACU or until catheter removal, up to 5 days | 
| Breakthrough opioid consumption (if required) | amount of opioids consumed | once a day from the arrival at PACU or until catheter removal, up to 5 days | 
| Incidence of adverse events | side effects related to the performance of the epidural block (eg, dural/vascular puncture, paresthesia) or breakthrough opioids (nausea, vomiting, pruritus, somnolence, respiratory depression) | Once a day from catheter insertion until removal, up to 5 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Abdomen/surgery, Thoracic Surgery