Evaluating the State of Microvessels by Minimum Rise Time (MRT01)

NCT ID: NCT02527070

Last Updated: 2016-10-17

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 33 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-09-30
• Study Completion Date: 2016-10-31

Brief Summary

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.

Detailed Description

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.

Conditions

Healthy

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: SINGLE

Study Groups

Red LED

Light emitting diodes, 670 nm, 50 mW/cm2, Quantum Warp10 (Quantum Devices Inc, Barneveld, WI, USA); RESPeRATE; Heat/cold provocation

Group Type: EXPERIMENTAL

RESPeRATE (Paced Breathing)

Intervention Type: DEVICE

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.

Quantum Warp10 (Red LED)

Intervention Type: DEVICE

Heat/cold provocation

Intervention Type: OTHER

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.

Near Infrared LED

Light emitting diodes, 830 nm, 55 mW/cm2, Omnilux new-U (Photomedex, Horsham, PA, USA); RESPeRATE; Heat/cold provocation

Group Type: ACTIVE_COMPARATOR

RESPeRATE (Paced Breathing)

Intervention Type: DEVICE

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.

Omnilux new-U (Near Infrared LED)

Intervention Type: DEVICE

Heat/cold provocation

Intervention Type: OTHER

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.

Interventions

RESPeRATE (Paced Breathing)

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.

Intervention Type: DEVICE

Quantum Warp10 (Red LED)

Intervention Type: DEVICE

Omnilux new-U (Near Infrared LED)

Intervention Type: DEVICE

Heat/cold provocation

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.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

1. Healthy males and females, between 18 and 65 years of age.

2. Willing to sign informed consent.

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. 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.

5. Having any illness that might affect the vasculature, such as diabetes (type I or II)

6. Suffering from significant concurrent illness, such as cardiac disorders, , or pertinent neurological disorders.

7. As per the Investigator's discretion, any physical or mental condition which might make it unsafe for the subject to participate in this study.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Sheba Medical Center

OTHER_GOV

Sponsor Role: collaborator

Afeka, The Tel-Aviv Academic College of Engineering

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Moshe Halak, MD

Role: PRINCIPAL_INVESTIGATOR

Sheba Medical Center

Zehava Blechman, PhD

Role: STUDY_DIRECTOR

Afeka, Tel-Aviv Academic College of Engineering

Locations

Afeka, Tel-Aviv Academic College of Engineering

Tel Aviv, , Israel

Countries

Israel

References

Gavish B. Plethysmographic characterization of vascular wall by a new parameter--minimum rise-time: age dependence in health. Microcirc Endothelium Lymphatics. 1986-1987;3(3-4):281-96.

Reference Type: RESULT

PMID: 3431526 (View on PubMed)

Other Identifiers

2080-15-SMC

Identifier Type: -

Identifier Source: org_study_id