Device Characterizes and Monitors Raynaud's Disease

A miniature device helps physicians characterize Raynaud's disease and measure treatment effectiveness.

The small, low-cost monitor wraps around a patient's finger and is secured with a bandage or medical tape. It contains two sensors that alternately record skin and ambient temperatures, indicators of surface blood flow, every 36 seconds. Interactive controls permit a patient to record the date and time of a suspected Raynaud's attack. A week's data are held by the monitor's electronics and are retained even if the device's power is unexpectedly interrupted.

Physicians can easily download data into a computer or personal digital assistant (PDA). Software developed by APL enables physicians to quickly and easily display and plot data, which could be done during a patient's appointment to provide real-time feedback. The monitoring system's batteries store enough energy to operate for several months, and devices can be cleaned and reinitialized for use with multiple patients.

Triggered by cold temperatures or stress, Raynaud's is characterized by numbness and coldness in the fingers, toes, ears, and/or nose when blood vessels in those areas constrict during attacks. Insufficient blood flow near the skin's surface also causes patients to experience skin color changes and varying levels of discomfort. Limited blood flow to the extremities can potentially lead to permanent loss of function. Raynaud's can occur on its own, or be secondary to another condition, such as auto-immune disorders like scleroderma or lupus

The Ambulatory Raynaud's monitor is a tiny, Band-Aid-like device that enables physicians to objectively characterize a patient's condition, determine its severity, and measure symptoms in real time, said Dr. Frederick Wigley, director of the Hopkins Scleroderma Center and a U.S. leading scleroderma expert, who asked the Johns Hopkins University Applied Physics Laboratory (APL, Laurel, MD, USA) to develop the device after reading about APL's work developing miniature devices for spacecraft. Until now, Raynaud's research has been crippled without such a device.

The device recently underwent initial testing on patients with Raynaud's being treated at the Johns Hopkins Medical Institutions. Patients wore a monitor for one week in their homes, pressing an event button on the device to indicate when a Raynaud's event was occurring. The data--processed by APL engineers and evaluated by the hospital physicians-- indicates Raynaud's events can be successfully identified. Patients said the devices are comfortable and easy to use. The data from this preliminary study suggest that the monitor can help scientists and physicians learn more about Raynaud's phenomenon and help investigators evaluate the effectiveness of drugs being developed to treat this disease, said APL's Binh Le, one of the inventors of the device.

In addition to monitoring Raynaud's patients, this platform technology could be used for an array of other medical or monitoring applications. The monitor could be modified to measure skin temperature of patients at risk for developing cardiovascular disease by tracking endothelial function (how small blood vessels regulate local blood flow to the tissues). Measuring skin temperature in various real-life situations may provide a noninvasive method to determine vascular responses in health and in various disease states.


Related Links:
Johns Hopkins University Applied Physics Laboratory