NCT02527070

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

Evaluating an Optical Index (Minimum Rise Time) as a Measure for the State of Microvessels

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 33 (actual)
• Sponsor: Afeka, The Tel-Aviv Academic College of Engineering · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

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

Interventions

Type	Name	Description
DEVICE	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.
DEVICE	Quantum Warp10 (Red LED)
DEVICE	Omnilux new-U (Near Infrared LED)
OTHER	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.

Timeline

• Start date: 2015-09-01
• Primary completion: 2016-06-01
• Completion: 2016-10-01
• First posted: 2015-08-18
• Last updated: 2016-10-17

Locations

1 site across 1 country: Israel