The WELMO system was successfully validated in the first pilot clinical examination carried out at the premises of the Department of Anaesthesiology and Intensive Care Medicine at the University Medical Centre Schleswig-Holstein, Campus Kiel, in Germany.
This first validation study of the WELMO system with integrated chest sound recording, electrical impedance tomography (EIT) and accelerometry was realized as a prospective observational single-centre study on healthy subjects. It was conducted according to the current ethical and legal requirements for clinical examinations with medical devices according to the Medical Device Regulation 2017/745 and approved by the responsible authorities, the Ethics Committee of the Medical Faculty of the Kiel University and the German Federal Institute for Drugs and Medical Devices in Bonn, Germany. The study was registered at the German Clinical Trial Registry – an open‐access primary registry of clinical trials approved by the World Health Organization (record number DRKS00023703).
Twenty study participants (10 women and 10 men) in the age range between 23 and 65 years were recruited. The examination time ranged between 35 min to 76 min, the duration of the recordings was between 811 s to 1054 s. The study protocol comprised 14 phases during which the subjects were wearing the WELMO vests continuously under a variety of conditions. These included phases of quiet tidal breathing, deep breathing, ventilation manoeuvres, breathhold, upright straight sitting and slightly leaned forward position, as well as three horizonal postures. A questionnaire‐based survey was conducted among the study participants to obtain individual feedback regarding different vest properties and their acceptance. The safety of the WELMO vest was assessed by the number of adverse events.
The main study results are the following: The registration of the study participants using the WELMO Health Care Professional application was operational. The WELMO Patient application allowing the logging‐in of the registered subjects, data streaming, recording, annotation of the study protocol phases, download of the data from the vest to the WELMO study tablet and upload of the recordings to the WELMO back‐end server were also fully functional.
All 20 study participants completed the full 14‐phase study protocol. All bio‐signals (chest sounds, EIT and posture/activity) were recorded. The sound recordings showed that heart and lung sounds were generally audible. In spite of detected noise, the quality of lung sounds was still deemed sufficient for identification of coughing, speech and wheezes. The EIT data analyses revealed that EIT correctly identified all ventilation‐ and posture‐related changes in chest electrical bioimpedance during the individual study protocol phases. The accelerometer signals reliably identified the different body postures. The comfort of wearing and vest properties were positively rated. The study participants especially appreciated the very good thermoregulatory properties of the garment, the pleasant sensation of the textile on the skin and the fact that the WELMO vests did no restrict their breathing activity. The use of the WELMO vests was safe, no adverse events occurred.
In summary, it can be concluded that the first WELMO pilot study confirmed the functionality and safety of the WELMO system and the high level of its acceptance by the study participants. This is the prerequisite for the second validation of the second WELMO pilot study on patients with lung diseases, currently carried out at the Aristotle University in Thessaloniki, in Greece.
Christian-Albrechts-Universität zu Kiel