Evaluating the State of Microvessels by Minimum Rise Time (MRT01) (MRT01)
Evaluating an Optical Index (Minimum Rise Time) as a Measure for the State of Microvessels
Photoplethysmography (PPG) is a simple uncalibrated optical method of monitoring variations in skin blood volume. The objective of the current study is to investigate a potential relationship between MRT (minimum rise time, in time units) a measure derived from PPG and the state of microvessels.
This study includes a 1-2 hour single session per subject during which PPG and other microvascular and systemic variables will be monitored in response to non-invasive interventions that are known to elicit microvascular responses.
Aperçu de l'étude
Statut
Les conditions
Description détaillée
Photoplethysmography (PPG) is a simple uncalibrated optical method of monitoring variations in skin blood volume. A major limitation of PPG is the lack of a quantitative method for calibrating this signal. A method that provides an absolute measure (in time units) called 'minimum rise time' (MRT) was published in 1985 by Dr. Benjamin Gavish, one of the study investigators. However, a possible relationship between MRT and the state of arterioles that determines the microvascular flow has never been investigated. Such relationship, if validated, could have clinical impact in noninvasive diagnosis of vascular diseases and monitoring microvascular response to treatments that affect at both clinic and home setting.
The objective of the current study is to investigate a potential relationship between variations of MRT (minimum rise time, in time units) and microcirculatory variables induced by interventions that are expected to have acute effect on the state of arterioles and the tissue oxygenation.
This study includes a single 1-2 hour session per subject, during which PPG and other microvascular and systemic variables will be monitored in healthy volunteers 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, and local temperature changes. The experimental sessions will be conducted at the Afeka College by the study investigators.
Type d'étude
Inscription (Réel)
Phase
- N'est pas applicable
Contacts et emplacements
Lieux d'étude
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Tel Aviv, Israël
- Afeka, Tel-Aviv Academic College of Engineering
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Critères de participation
Critère d'éligibilité
Âges éligibles pour étudier
Accepte les volontaires sains
Sexes éligibles pour l'étude
La description
Inclusion Criteria:
- Healthy males and females, between 18 and 65 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.
Plan d'étude
Comment l'étude est-elle conçue ?
Détails de conception
- Objectif principal: Diagnostique
- Répartition: Randomisé
- Modèle interventionnel: Affectation parallèle
- Masquage: Seul
Armes et Interventions
Groupe de participants / Bras |
Intervention / Traitement |
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Expérimental: Red LED
Light emitting diodes, 670 nm, 50 mW/cm2, Quantum Warp10 (Quantum Devices Inc, Barneveld, WI, USA); RESPeRATE; Heat/cold provocation
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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.
Immersion of one foot in a warm water bath ( 43-45 degrees C) for few seconds and then immersion of the same foot in cold water bath (5-7 degrees C) for 1 min.
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Comparateur actif: Near Infrared LED
Light emitting diodes, 830 nm, 55 mW/cm2, Omnilux new-U (Photomedex, Horsham, PA, USA); RESPeRATE; Heat/cold provocation
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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.
Immersion of one foot in a warm water bath ( 43-45 degrees C) for few seconds and then immersion of the same foot in cold water bath (5-7 degrees C) for 1 min.
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Que mesure l'étude ?
Principaux critères de jugement
Mesure des résultats |
Délai |
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MRT as measured from finger Photoplethysmography in response to changes in breathing rate
Délai: Change from baseline to up to 1 minute after termination of 2 minutes of constant breathing rate (15, 10, and 6 breath/min)
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Change from baseline to up to 1 minute after termination of 2 minutes of constant breathing rate (15, 10, and 6 breath/min)
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MRT as measured from finger Photoplethysmography in response to light source
Délai: Change from immediately before exposure to light source to up to 10 minutes after exposure to light source
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Change from immediately before exposure to light source to up to 10 minutes after exposure to light source
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MRT as measured from finger Photoplethysmography in response to temperature changes
Délai: Change from immediately before exposure to temperature provocations to up to 2 minutes after exposure to warm water, and up to 2 minutes after exposure to cold water
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Change from immediately before exposure to temperature provocations to up to 2 minutes after exposure to warm water, and up to 2 minutes after exposure to cold water
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Mesures de résultats secondaires
Mesure des résultats |
Délai |
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Capillary blood flow (red blood cell velocity or flux in 'perfusion units') as measured by laser doppler
Délai: At baseline, 1 minute after each changes in breathing rate, 5 and 10 minutes after exposure to light source, 1 minutes after each exposure to temperature changes
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At baseline, 1 minute after each changes in breathing rate, 5 and 10 minutes after exposure to light source, 1 minutes after each exposure to temperature changes
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Transcutaneous oxygen pressure (tcpO2 in mmHg)
Délai: At baseline, 1 minute after each changes in breathing rate, 5 and 10 minutes after exposure to light source, 1 minutes after each exposure to temperature changes
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At baseline, 1 minute after each changes in breathing rate, 5 and 10 minutes after exposure to light source, 1 minutes after each exposure to temperature changes
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Collaborateurs et enquêteurs
Collaborateurs
Les enquêteurs
- Chercheur principal: Moshe Halak, MD, Sheba medical center
- Directeur d'études: Zehava Blechman, PhD, Afeka, Tel-Aviv Academic College of Engineering
Publications et liens utiles
Dates d'enregistrement des études
Dates principales de l'étude
Début de l'étude
Achèvement primaire (Réel)
Achèvement de l'étude (Réel)
Dates d'inscription aux études
Première soumission
Première soumission répondant aux critères de contrôle qualité
Première publication (Estimation)
Mises à jour des dossiers d'étude
Dernière mise à jour publiée (Estimation)
Dernière mise à jour soumise répondant aux critères de contrôle qualité
Dernière vérification
Plus d'information
Termes liés à cette étude
Autres numéros d'identification d'étude
- 2080-15-SMC
Plan pour les données individuelles des participants (IPD)
Prévoyez-vous de partager les données individuelles des participants (DPI) ?
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