Determination of the Duration of Action of a Lidocaine and a Bupivacaine Digital Nerve Block in Human Volunteers

Study Overview
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Brief Summary
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The duration of the autonomic (sympathetic) block will last longer than the sensory block. The duration of the increased perfusion index will last longer than either the sympathetic or sensory block.

Detailed Description
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The Masimo SpHb™ (SpHb) is a device used to monitor the blood hemoglobin level via a sticky sensor connected to a finger. Our results from 2 recent studies undertaken with this device concluded: 1) that it is not always accurate when the finger is cold such as during surgical blood loss, and 2) a local nerve block to the finger improved the finger temperature and the accuracy of the device. Our purpose is to investigate the duration of effect of two local nerve blocking drugs (lidocaine and bupivacaine - both FDA approved drugs in routine use) in a finger on each hand. Having a better understanding of how long the nerve block lasts could help determine when an additional block might be necessary to maintain the accuracy of the device during surgical blood loss. We previously listed the primary outcome for this study as the time until return to baseline finger temperature. However, in blinded looks at the data it became clear that defining time until return to baseline from the serial temperature measurements in an objective fashion would be extremely difficult and potentially controversial. We have modified the primary outcome to be the change in the average temperature from baseline to post-intervention.

Official Title
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Determination of the Duration of Action of a Lidocaine and a Bupivacaine Digital Nerve Block in Human Volunteers

Conditions
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Onset and Duration of a Digital Nerve Block

Intervention / Treatment
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* Drug: Lidocaine Digital Nerve Block
* Drug: Bupivacaine Digital Block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Non-smokers Exclusion Criteria: History of allergic response to local anesthetics BMI >25 Pregnant of nursing Current smokers or past smokers of > 1 pack year history Neurological deficit and/or injury in the upper extremities Current respiratory infection Per investigator judgement, would not be suitable for study

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: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Lidocaine<br>Lidocaine 1% Digital Nerve Block (2 cc) | Drug: Lidocaine Digital Nerve Block<br>* Lidocaine 1% Digital Nerve Block (2 cc<br>|
| Active Comparator: Bupivacaine<br>Bupivacaine 0.25% Digital Block (2 cc) | Drug: Bupivacaine Digital Block<br>* Bupivacaine 0.25% Digital Block (2 cc)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Change in the Average Finger Temperature From Baseline to Post-intervention. |  | 30 minutes prior and 240 minutes post intervention. |