How Does a Wound Dressing With Sensors Monitor the Healing Process?

March - April 2023

How Does a Wound Dressing With Sensors Monitor the Healing Process?

Editorial Summary

This article describes and considers new technology which uses sensors integrated into wound dressings to provide data on the wound healing status. Discussed is the development of this technology, how it is constructed and used, and the possibilities for future implementation in wound care.

Introduction

For clinicians, what is happening under a dressing is a mystery that can only be solved by uncovering the wound. Since this can be as different as the wound is healing or is infected, technology that could provide information on the wound status could be revolutionary. This is precisely what a collaboration between code’n’ground AG and the Private University of Applied Sciences for Business and Technology (phwt) has been working towards since 2020.

What are the goals?

The goal is to ‘elevate primary wound healing to a new digital level using sensor technology and artificial intelligence’. To expand further, this would require evidence that sensor technology assisted with connected AI could measure and provide information such as temperature and moisture under a dressing, giving the clinician an indication of wound healing status. By dividing the project between the technical challenge involved with the wound dressing, which was undertaken by the Private University of Applied Sciences for Business and Technology (phwt), and the software component to develop the AI, which was lead by code’n’ground, this goal has been achieved.

What is the technology?

The sensor would need to capture the relevant parameters that would indicate a disruption in wound healing and/ or infection, and would have to be easily incorporated into the wound dressing. This was approached by incorporating

conductive structures within a plastic film, which is then combined with the dressing allowing monitoring of the temperature and humidity underneath; a significant increase in either parameter could be an indication of inflammation, infection and/ or disruption of healing.

The sensor structure was comprised of an ultrathin layer of copper measuring a few micrometers; the properties of this mean that if there is a change in temperature, the conductivity of this component will also change. The moisture is monitored by changes in electrical capacitance.

The plastic film is designed to be flexible and elastic, and crucially non-irritating or harmful to skin. The sensor structure is incorporated between two of these films, and combined with a thermal connection to the dressing. The dressing is contained in sterile packaging as any other; nursing staff may use it routinely by opening the packaging, applying the dressing and covering as usual with bandages.

The dressing collects, stores and sends data continuously; the AI then processes the data which is read by an app. Nursing staff can then access a wound assessment based on this data with the app. There is also an intention to make it possible for patients themselves to transmit the data, which again would be done with an app; the technology was developed with this in mind, and therefore the app is an integral part of the AI architecture.

Currently, in the hospital setting wounds are assessed when the dressing is changed; this

Prof Kai-Uwe Zirk

Center for Mechatronics and Electrical Engineering, phwt (Private Hochschule für Wirtschaft und Technik gGmbH)

Vechta, Germany

Mr Armin Haas

Member of the Executive Board, code’n’ground AG

Heidenheim an der Brenz, Germany

is the only time when clinicians can get any information on the healing status of the wound, before the wound is covered again. The smart dressing in comparison measures the temperature and moisture parameters throughout the healing process, which can amount to 30,000 measuring points. Parameters that relate to the correlation between wound healing and duration are also collected, as well as previously mentioned, moisture and temperature; an alarm will sound when the parameters are out of sync, indicating a problem. The nursing staff will then be able to assess the wound; so the sensor is actually the primary source of data.

The concept for the patient being able to transmit data themselves would work as follows: using the proposed app, the patient will be able to report any pain, feelings of tightness, or any other signs and symptoms of a problem with the wound healing process, infection, etc. This adds another facet to the approach of constant assessment of the wound; the implementation of this has always been part of the modelling, though this has not been done yet.

In this multi-faceted approach to assessment, feedback from healthcare professionals is another source of information. In the event that a wound has become infected,

the interventions performed (changing the bandage, administering antibiotics, etc.) would be recorded.

This would ultimately make available hugely valuable data, and it will be possible to analyze the success of interventions and perhaps draw conclusions on the most successful treatments and interventions in the future; ultimately, the goal is to support the medical team.

An obvious problem was to avoid making the dressing too cumbersome or uncomfortable, in that it has to contain a sensor. The technology can be made much smaller if in major production; currently the dressing is not as small as is ideal, due to the huge undertaking of development. In major production the data device could realistically be as small as 1.5cm in diameter and around 5 - 6mm in height.

In terms of this technology being introduced into the industry, and when and how this could happen, the function of the dressing has been proven with tests on technical models in the lab. An effort is underway to find interested partners who could support the project, and allow us to move onto the next step, which is to use the dressings on humans and process the data with AI.

How Does a Wound Dressing With Sensors Monitor the Healing Process?

Figure 1: Wound dressing with sensor and data logger.