Microcirculation
Conditions
Keywords
Photoniomodulation, low-level laser, microcirculatory blood flow
Brief summary
The objective of this study is to assess peripheral microcirculatory hemodynamic responses to photobiomodulation in participants with normal circulation and with functional peripheral vasoconstriction, using noninvasive thermography, photoplethysmography, and laser Doppler flowmetry.
Detailed description
This is a within-subject experimental study in which each participant completes two study sessions. Microvascular and systemic variables are continuously monitored in response to photobiomodulation delivered at either a blue or near-infrared wavelength, with each wavelength applied in a separate session. Each session includes a baseline period with controlled breathing, followed by photobiomodulation and a 20-minute post-intervention follow-up period. Peripheral microcirculatory responses are assessed using noninvasive thermography, photoplethysmography, and laser Doppler flowmetry.
Interventions
DEVICEPhotobiomodulation - Blue Wavelength
Photobiomodulation delivered at a blue wavelength (400-500 nm) to the hands during a single study session as part of a randomized crossover design.
DEVICEPhotobiomodulation - Near Infrared
Photobiomodulation delivered at a near-infrared wavelength (780-1100 nm) to the hands during a single study session as part of a randomized crossover design.
Sponsors
Hebrew University of Jerusalem
Afeka, The Tel-Aviv Academic College of Engineering
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
This is a within-subject crossover study in which participants receive photobiomodulation at blue and near-infrared wavelengths in separate sessions, with the order of exposure assigned in a crossover manner. Participants may present with functional peripheral vasoconstriction or normal peripheral temperature at baseline; these baseline characteristics will be used for subgroup analyses and do not define separate study arms.
Eligibility
Sex/Gender
ALL
Age
20 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
1. Healthy males and females, between 20 and 75 years of age. 2. Willing to sign informed consent. 3. Willing to participate in two separate sessions, one for each wavelength. 4. Able to avoid caffeine and alcohol for at least 3 hours before each session. 5. Able to sit comfortably with both hands at heart level for the full measurement duration.
Exclusion criteria
1. Currently smoking 2. Any abnormal skin condition in the area of light irradiation. 3. Pregnant, having given birth less than 3 months ago, and/or breastfeeding. 4. History of photosensitive conditions or use of photosensitizing medications 5. Suffering from significant concurrent illness, such as cardiac disorders or pertinent neurological disorders. 6. As per the Investigator's discretion, any physical or mental condition that might make it unsafe for the subject to participate in this study.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Capillary blood flow | Up to 1 hour | Capillary blood flow, expressed as red blood cell flux (perfusion units), measured continuously using laser Doppler flowmetry (≥10 Hz sampling rate) from baseline through the end of each study session. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Temperature distribution over hands measured by thermography | Up to 1 hour | Thermal images will be acquired using a FLIR infrared camera, and spatial temperature distribution over the hands will be analyzed. Images will be acquired at one-minute intervals from baseline through the end of each study session. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Photoplethysmography (PPG)-derived perfusion response | Up to 1 hour | Continuous photoplethysmography (PPG) will be recorded from the hand, and PPG-derived perfusion metrics (e.g., pulse amplitude and related indices) will be quantified to assess changes in peripheral microcirculation following photobiomodulation. |
Countries
Israel
Outcome results
None listed