Effect of Changing Physiological Conditions on Myogenic Oscillations: Pilot Study

Study Overview
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Brief Summary
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Spontaneous myogenic oscillations will be studied under general anesthesia using finger photoplethysmography. This pilot study will explore potential physiological conditions that will effect the amplitude and/or frequency of myogenic oscillations.

Detailed Description
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This is a single center, nonrandomized, nonblinded, interventional clinical pilot research study that plans to enroll 40 patients. Study will be conducted while subjects are under general anesthesia. Myogenic oscillations will be measured using finger photoplethysmography. Changes in the amplitude and/or frequency of these oscillations will be analyzed in response to the interventions. Arterial blood pressure will be recorded to verify the efficacy of the interventions. Six different interventions that will either lower or increase blood pressure will be applied to the subjects. Each subject will receive 1 or 2 of the six interventions. Each of the 6 interventions will be applied to 8 subject. The interventions that the subject will not be randomized. They will be determined by the subjects blood pressure immediately before the intervention to guarantee that the blood pressure manipulations are within a safe range. Data will be analyzed offline using Matlab.

Official Title
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A Pilot Study to Evaluate the Effect of Changing Physiological Conditions on the Amplitude and/or Frequency of Myogenic Oscillations

Conditions
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Vascular Diseases

Intervention / Treatment
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* Drug: Phenylephrine
* Drug: Dexmedetomidine
* Drug: Clevidipine
* Other: tetanic stimulus
* Other: Increased venous pressure
* Drug: Calcium Chloride


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Over 18 yrs of age Undergoing surgery in Moffitt-Long operating rooms Receiving general anesthesia Will have an intra-arterial catheter for clinical purposes Able to consent in english Exclusion Criteria: Under 18 years of age unable to provide informed consent Pregnancy

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Phenylephrine<br>Phenylephrine (100 ug/ml) infusion will be used to increase blood pressure by 20 mmHg | Drug: Phenylephrine<br>* blood pressure will be increased or decreased by using one of six interventions: phenylephrine (alpha-1 agonist), dexmedetomidine (alpha-2 agonist), clevidipine (Ca channel blocker, CaCl, tetanic stimulus and increase in venous pressure<br>* Other names: Neosynephrine;|
| Experimental: Dexmedetomidine<br>Dexmedetomidine infusion will be used to increase blood pressure by 20 mmHg | Drug: Dexmedetomidine<br>* blood pressure will be increased or decreased by using one of six interventions: phenylephrine (alpha-1 agonist), dexmedetomidine (alpha-2 agonist), clevidipine (Ca<br>* Other names: Precedex;|
| Experimental: Clevidipine<br>Clevidipine infusion will be used to increase blood pressure by 20 mmHg | Drug: Clevidipine<br>* blood pressure will be increased or decreased by using one of six interventions: phenylephrine (alpha-1 agonist), dexmedetomidine (alpha-2 agonist), clevidipine (Ca<br>* Other names: Cleviprex;|
| Experimental: Calcium Chloride<br>Calcium Chloride will be administered to increase blood pressure and to increase blood calcium concentration | Drug: Calcium Chloride<br>* CaCl will be administered to increase blood pressure and plasma calcium concentration<br>|
| Experimental: tetanic stimulus<br>A 5 second 70 mA tetanic stimulus will be used to increase peripheral vascular tone | Other: tetanic stimulus<br>* A 5 second 70 mA tetanic stimulus will be applied to elicit peripheral vasoconstriction (stress response)<br>|
| Experimental: Increased venous pressure<br>A 5 minute inflation of a noninvasive blood pressure cuff to 30 mmHg to increase venous pressure in the arm. | Other: Increased venous pressure<br>* A 5 minute inflation of a noninvasive blood pressure cuff to 30 mmHg to increase venous pressure in the arm with the pulse oximeter probes.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| myogenic oscillations | change in amplitude and/of frequency of myogenic oscillations | up to 5 minutes |