A flexible and low power telemetric sensing and monitoring system for chronic wound diagnostics

Background: Non-healing chronic wounds, such as venous leg ulcers, can be monitored non-invasively by using modern sensing devices and wireless technologies. The development of such a wireless diagnostic tool may improve chronic wound management by providing evidence on efficacy of treatments being provided. This paper presents a low-power portable telemetric system for wound condition sensing and monitoring. The system aims at measuring and transmitting real-time information of wound-site temperature, sub-bandage pressure and moisture level from within the wound dressing. Methods: Commercially available non-invasive temperature, moisture, and pressure sensors are interfaced with a telemetry device on a flexible 0.15 mm thick printed circuit material to construct a light-weight, non-invasive, biocompatible, and low-power sensing device. The real-time data obtained is transmitted wirelessly to a portable receiver which displays the measured values. The performance of the whole telemetric sensing system is validated on a mannequin leg using commercial compression bandages and dressings. A number of trials on a healthy human volunteer are performed where treatment conditions were emulated using various compression bandage configurations. Results: A reliable and repeatable performance of the system is achieved under compression bandage and with minimal discomfort to the volunteer. The system is capable of reporting instantaneous changes in bandage pressure, moisture level and local temperature at wound site with average measurement resolutions of 0.5 mmHg, 3.0% RH, and 0.2 degrees C respectively. Effective range of data transmission is 4-5 m in an open environment. Conclusions: A flexible and non-invasive sensing system is developed to acquire and wirelessly transmit wound parameters from within a compression bandage and wound dressing worn on a human limb. Pre-clinical results on a healthy human subject suggest its clinical usability and value to health practitioners. However, further performance evaluations of the device on a wider population of healthy human subjects and on patients with chronic wounds are required to confirm its medial usefulness and to quantify its real impact on chronic wound management.