Monitoring of Venous Ulcers Using a Bioimpedance Measurement Based Method and System

The technical principle of the monitoring method is based on the quasimonopolar bioimpedance measurement. The measurement system consists of a bioimpedance measuring device, a wound dressing with electrodes (eDressing) and a mobile application for use with a mobile phone.

The electrode dressing is placed on top of a wound, in contact with the wound tissue. The other necessary dressing layers (such as absorbent dressings and compression bandages) are placed over the electrode dressing. The electrode dressing is kept on the wound for maximum of seven consecutive days. The electrode dressing can be removed and replaced when needed due to medical reasons. Other dressings can be changed considered necessary.

During a study subject visit, the bioimpedance measurement is made using the device, the uppermost dressings are opened carefully and it is ensured that the wound condition is as expected. Upon the replacement of the electrode dressing, the wound is photographed and documented. The wound area is measured, and the findings are recorded.

A maximum of 20 subjects with venous ulcers will be recruited for the study in two study sites (Gdansk, Poland and Tampere, Finland).

Adult subjects (≥18 years) with venous ulcer who are applicable for compression therapy treatment, whose ulcer is not wider than 5 cm and does not excrete excessively can be recruited to the study. Previous surgical venous procedure is not an exclusion criterion for enrollment, but surgical procedure can not be performed during the study.

A subject shall visit the clinic 2-3 times a week, according to the doctor's or study nurse's assessment. Wound healing is monitored until the wound re-epithelized (>90% of initial wound surface area) or maximum two months. Thus, there will be a maximum of 24 study visits per subject.

In addition to scientific objectives, the results of this study are also used as part of clinical evidence when submitting the technical documentation to Notified Body for assessment of the conformity of the device before being placed on the market.

Inclusion criteria

• Age at least 18 years
• The subject has a chronic lower extremity ulcer with a primary etiology of venous insufficiency. The previous venous procedure is not an obstacle to the study
• Compression therapy can be implemented
• The wound is not wider than 5 cm and the electrode dressing can be placed on the wound as intended. The wound should be located above the ankle, on the skin area where the electrode dressing can be placed properly.
• The wound is not deep with steep edges or cavity-like
• The wound is not highly excreting
• The wound can be expected to heal within two months (area reduced ≥ 90% from baseline)
• The subject gives consent to the study and commits to following the instructions of the medical staff

Exclusion criteria

• Clinical wound infection at the time of the study
• The subject has an intravenous (in Tampere: A venous operation) procedure within 2 months
• Significant arterial circulatory disorder or adherence problem that prevents compression therapy (in Tampere: Contraindication for compression therapy, e.g. significant arterial circulatory disorder or severe heart failure)
• Subject movement 2-3 times a week during the study to the study site is difficult to arrange (in Tampere: Subject not able to commit to study visits 2-3 times a week.)
• Diagnosed epoxy resin allergy
• Any other reasons of potential study subject non-compliance by the opinion of the investigator

Additional local exclusion criteria in Tampere site:

• Special groups, such as pregnant women/patients trying to conceive during the study or patients with reduced autonomy
• Subject with any implantable electrical device. Such as pacemaker or implanted defibrillator. Patient has other electrically conductive implanted material in legs. Such as a metallic prostheses.