Continuous Femoral Nerve Blocks: Relative Effects of Basal Infusion and Bolus Doses on Sensory and Motor Function

Study Overview
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Brief Summary
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This is a research study to determine if the way local anesthetic- or numbing medication- is delivered through a tiny tube next to the nerves that go to the thigh affects the strength and sensation in the thigh.

Detailed Description
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Specific Aim: Research study to test the null hypothesis that differing the delivery method (continuous basal infusion vs. repeated bolus doses) but providing an equal total dose of Ropivacaine has no impact on quadriceps muscle strength. These results will help define the optimal delivery method of local anesthetic used for continuous peripheral nerve blocks and help guide future research in this clinically relevant area.

Official Title
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Continuous Femoral Nerve Blocks: Relative Effects of Basal Infusion and Bolus Doses on Sensory and Motor Function

Conditions
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Nerve Block

Intervention / Treatment
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* Procedure: Continuous Infusion
* Procedure: Bolus Administered


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years of age or older willing to have bilateral femoral perineural catheters place with a subsequent ropivacaine infusion and motor/sensory testing for 9 hours willing to stay overnight in the UCSD GCRC/CTRI to allow dissipation of local anesthetic infusion effects by the following morning. Exclusion Criteria: current daily analgesic use opioid use with in the previous 4 weeks any neuro-muscular deficit of either femoral nerves and/or quadriceps muscles pregnancy incarceration

Ages Eligible for Study
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Minimum Age: 18 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Continuous Infusion<br>Each subject will have one lower extremity (Right or Left) randomized to receive a perineural catheter with a continuous infusion of local anesthetic and then the outcomes will be measured. | Procedure: Continuous Infusion<br>* Extremity randomized continuous infusion will be given a peripheral nerve block and 5cc of Ropivacaine will be administered continuously every hour by a pain pump. Outcome measures will be tested.<br>|
| Active Comparator: Bolus Administration<br>The opposite lower extremity (right or left) will be randomized to receive a perineural catheter with the local anesthetic being delivered via a bolus as opposed to continuous as is the case with their other extremity. The outcome measures will then be assessed as described. | Procedure: Bolus Administered<br>* Extremity randomized continuous infusion will be given a peripheral nerve block and 5cc of Ropivacaine will be administered using a bolus every hour by a pain pump. Outcome measures will be tested.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quadriceps Femoris Muscle Strength | The primary end point will be the quadriceps femoris maximum voluntary isometric contraction (MVIC) expressed as percentage of the pre-ropivacaine MVIC: post/pre x 100; with the two sides of each subject compared with each other. | Every Hour for 14 hours | 
| Quadriceps Femoris Muscle Strength | The primary end point will be the quadriceps femoris maximum voluntary isometric contraction (MVIC) expressed as percentage of the pre-ropivacaine MVIC: post/pre x 100; with the two sides of each subject compared with each other. | Hour 22 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle Strength | This will be evaluated using a portable isometric force dynamometer to measure the maximum voluntary isometric contraction (MVIC) in a seated position. | Every Hour for 14 hours | 
| Sensory Level | Evaluated in the seated position, using Transcutaneous Electrical Stimulation (TES)in the same manner as outlined in the current anesthesia literature. The current will be increased from 0mA until the subject identifies sensation at which time the current is recorded as the TES value and the nerve stimulator is turned off. | Every Hour for 14 hours | 
| Muscle Strength | This will be evaluated using a portable isometric force dynamometer to measure the maximum voluntary isometric contraction (MVIC) in a seated position. | Hour 22 | 
| Sensory Level | Evaluated in the seated position, using Transcutaneous Electrical Stimulation (TES)in the same manner as outlined in the current anesthesia literature. The current will be increased from 0mA until the subject identifies sensation at which time the current is recorded as the TES value and the nerve stimulator is turned off. | Hour 22 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Femoral, Nerve Block, Bolus, Continuous Infusion, UCSD, Perineural Catheter, Volunteer, lower extremity nerve blocks