Effect of Location of Tetanic Stimuli on Photoplethysmogram Under General Anesthesia

Study Overview
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Brief Summary
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The effect of the location of tetanic stimulus on photoplethysmography signals will be studied in patients under general anesthesia.

Detailed Description
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A 5 second 100 Hz 70 mA tetanic stimulus will be applied to three different locations (Ulnar nerve, Facial nerve, Posterior Tibial nerve) in a random order in patients who are under general anesthesia. Tetanic stimuli are used routinely during general anesthesia to assess effectiveness of neuromuscular blockade. These tetanic stimuli are noxious stimuli that elicit a stress response which can be quantified using photoplethysmography. This study investigates if the magnitude of the tetanus induced stress response is dependent on the location of the tetanic stimulus as measured by photoplethysmography.

Official Title
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Effect of Tetanic Stimuli on Photoplethysmogram During General Anesthesia

Conditions
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Stress Reaction

Intervention / Treatment
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* Device: Tetanic Stimulus


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Surgical patients Undergoing general anesthesia Able to consent in english 18 years of age or older Exclusion Criteria: Under 18 years of age unable to consent in english receiving regional anesthesia

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: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Tetanic Stimulus<br>all participants receive the same intervention | Device: Tetanic Stimulus<br>* 5 second 100 Hz 70 mA tetanic stimulus will be applied to three different locations in a random order<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tetanic stimulus induced change in photoplethysmography light transmission (in analog to digital units as measured using a pulse oximeter) from pre stimulus baseline | Tetanic stimulation will induce peripheral vasoconstriction. This will be measured using photoplethysmography. During peripheral vasoconstriction the light transmission through finger will increase. The primary outcome will be the maximum change in light transmission (as measured by photoplethysmography) within 60 seconds after a tetanic stimulus as compared to pre stimulus baseline values. These maximal light transmission changes will be compared between the three different tetanic stimulus sites | Maximum light transmission change from pre tetanic stimulus baseline within 60 seconds after the tetanic stimulus | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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photoplethysmography, stress response