Distribution, Pharmacokinetics and Extent of Sensory Blockade in ESP Blocks

Study Overview
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Brief Summary
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The primary objectives of this study are to define the extent of dermatomal anesthesia and anatomical spread of injectate (as defined by MRI imaging) that is provided by an ESP block at the T5 level, using twenty milliliters of 0.5% ropivacaine. The secondary objectives include: 1) the measurement of changes in hemodynamic parameters associated with the ESP block, 2) the duration of sensory effects provided by ropivacaine with or without epinephrine, 3) the venous plasma concentration of ropivacaine associated at various time intervals after completion of the ESP block.

Official Title
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A Volunteer Study to Determine the Anatomical Distribution of Injectate, the Extent of Sensory Block, and the Pharmacokinetics of Ropivacaine Following Erector Spinae Plane (ESP) Blocks.

Conditions
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Distribution of Ropivacaine in Erector Spinae Plane Block

Intervention / Treatment
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* Drug: Ropivacaine
* Drug: Epinephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adults aged 18 to 60 inclusive Weight between 60 and 100 kg inclusive Height 160 to190 cm inclusive Exclusion Criteria: Pregnant females Chronic medical condition requiring medication History of previous major spinal, abdominal or thoracic surgery Congenital abnormalities of the spine, back, thorax or abdomen History of major trauma to the thorax or abdomen; Allergy to ropivacaine or other amide local anesthetics The presence of any metallic implant in their body Any contraindication to magnetic resonance imaging as determined by completion of a standard questionnaire administered to all patients undergoing magnetic resonance imaging. Allergy to Gadolinium radiological contrast agent.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: This will be a randomized,double blinded, controlled study.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Ropivacaine with Epinephrine<br>Group RE will have 20mL of 0.5% Ropivacaine with epinephrine injected at the left or right T5 transverse process. | Drug: Ropivacaine<br>* injection of 20mL of 0.5% Ropivacaine at the left or right T5 transverse process<br>Drug: Epinephrine<br>* injection of 20mL epinephrine in combination with ropivacaine at the left or right T5 transverse process<br>|
| Active Comparator: Ropivacaine without Epinephrine<br>Group R will have 20mL of 0.5% Ropivacaine without epinephrine injected at the left or right T5 transverse process. | Drug: Ropivacaine<br>* injection of 20mL of 0.5% Ropivacaine at the left or right T5 transverse process<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Extent of dermatomal sensory loss | A consultant anesthesiologist blinded to the randomization allocation will perform a sensory assessment for loss of sensation to cold using ethanol on the skin | 0 to 360 minutes from the time of the ESP block | 
| Duration of sensory loss | A consultant anesthesiologist blinded to the randomization allocation will perform a sensory assessment for loss of sensation to cold using ethanol on the skin | 0 to 360 minutes from the time of the ESP block | 
| Anatomical extent of injectate spread using MRI | The subject will undergo two MRIs to determine the spread of the anesthetic. | 30 and 90 minutes from the time of the ESP block | 
| Venous plasma concentration of ropivacaine at periodic time intervals | 3 ml of blood will be obtained from the Intravenous line already placed in the subject prior to performing the block. | These samples will be repeated at 20, 40, 60, 90, 120, and 240 minutes after completion of the injection of active drug. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood pressure at periodic time intervals | Non- invasive monitoring of blood pressure every 5 minutes. | Up to 360 minutes from the time of the ESP block | 
| Any adverse effects or side effects related to injection of the medications |  | 0-3 days after the block is complete | 
| ECG at periodic time intervals | Recording ECG every 5 minutes | Up to 360 minutes from the time of the ESP block |