Evaluation of Peripheral Microcirculation Hemodynamics Following Various Changes Based on Noninvasive Thermography

Study Overview
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Brief Summary
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The objective of the current study is to investigate the hemodynamic changes in the peripheral microcirculation system as a response to various changes, using noninvasive thermography and laser doppler

Detailed Description
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This study includes a single session per subject. Microvascular and systemic variables will be monitored in response to a number of non-invasive interventions/device that are approved for clinical use and known to elicit microvascular responses. These interventions are applied consecutively, include breathing at different rates, low power visible light in the red-to-near-infrared range, increase in local temperature, and changes in the arm position.

Official Title
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Evaluation of Peripheral Microcirculation Hemodynamics Following Various Changes Based on Noninvasive Thermography: A Prospective, Randomized, Controlled Trial

Conditions
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Microcirculation

Intervention / Treatment
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* Device: Omnilux new-U (Red LED)
* Device: Omnilux new-U (Near infrared LED)
* Device: RESPeRATE
* Device: Heating bag


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy males and females, between 23 and 45 years of age. Willing to sign informed consent Exclusion Criteria: Currently smoking Any abnormal skin condition in the area of light irradiation. Pregnant having given birth less than 3 months ago, and/or breastfeeding. Having a history of diseases stimulated by heat, such as recurrent Herpes Simplex in the treated area, unless treatment is conducted following a prophylactic regimen. Having any illness that might affect the vasculature, such as diabetes (type I or II) Suffering from significant concurrent illness, such as cardiac disorders or pertinent neurological disorders. As per the Investigator's discretion, any physical or mental condition which might make it unsafe for the subject to participate in this study.

Ages Eligible for Study
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Minimum Age: 23 Years
Maximum Age: 45 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
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Red LED<br>Light emitting diodes, 633 nm, 70 mW/cm2, Omnilux new-U (Red LED) (Photomedex, Horsham, PA, USA); RESPeRATE; Heating bag | Device: Omnilux new-U (Red LED)<br>* The left wrist (including area of radial artery) will be illuminated with the Omnilux new-U (Red LED) light source, while the right wrist will not be illuminated<br>Device: RESPeRATE<br>* The subjects will be guided by a digital metronome to breath at 15, 10, and 6 breaths/min for 2 minutes each using the metronome function of the device RESPeRATE (InterCure, Israel) that guides breathing using musical tones played at selectable rhythm<br>Device: Heating bag<br>* Applying a standard 10X13 [cm] heating bag on the surface of the hand at 43-45 degree Celsius for 10 seconds<br>|
| Active Comparator: Near Infrared LED<br>Light emitting diodes, 830 nm, 55 mW/ cm2, Omnilux new-U (Near infrared LED) (Photomedex, Horsham, PA, USA); RESPeRATE metronome; Heating bag | Device: Omnilux new-U (Near infrared LED)<br>* The left wrist (including area of radial artery) will be illuminated with the Omnilux new-U (Near infrared LED) light source, while the right wrist will not be illuminated<br>Device: RESPeRATE<br>* The subjects will be guided by a digital metronome to breath at 15, 10, and 6 breaths/min for 2 minutes each using the metronome function of the device RESPeRATE (InterCure, Israel) that guides breathing using musical tones played at selectable rhythm<br>Device: Heating bag<br>* Applying a standard 10X13 [cm] heating bag on the surface of the hand at 43-45 degree Celsius for 10 seconds<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Capillary blood flow | Capillary blood flow (red blood cell velocity or flux in 'perfusion units') as measured by laser doppler (Biopac™ System, Inc, USA). This is a continuous measurement (at least 10 Hz sampling rate) from baseline to end of experiment. | Up to 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Temperature distribution over hands measured by thermography | Thermographic images will be photographed with a FLIR camera and temperature distribution will be analysed. Photos will be taken every minute from baseline to end of experiment. | Up to 1 hour | 
| Tissue oxygenation (tcPO2) | Tissue oxygenation (tcPO2) measured by electrodes mounted on both hands (Perimed™ system, Sweden). This is a continuous measurement (at least 10 Hz sampling rate) from baseline to end of experiment. | Up to 1 hour |