Wearable pulmonary monitoring system with integrated functional lung imaging and chest sound recording: a clinical investigation in healthy subjects.

Objective.Current wearable respiratory monitoring devices provide a basic assessment of the breathing pattern of the examined subjects. More complex monitoring is needed for healthcare applications in patients with lung diseases. A multi-sensor vest allowing continuous lung imaging by electrical impedance tomography (EIT) and auscultation at six chest locations was developed for such advanced application. The aims of our study were to determine the vest's capacity to record the intended bio-signals, its safety and the comfort of wearing in a first clinical investigation in healthy adult subjects.Approach.Twenty subjects (age range: 23-65 years) were studied while wearing the vests during a 14-step study protocol comprising phases of quiet and deep breathing, slow and forced full expiration manoeuvres, coughing, breath-holding in seated and three horizontal postures. EIT, chest sound and accelerometer signals were streamed to a tablet using a dedicated application and uploaded to a back-end server. The subjects filled in a questionnaire on the vest properties using a Likert scale.Main results.All subjects completed the full protocol. Good to excellent EIT waveforms and functional EIT images were obtained in 89% of the subjects. Breathing pattern and posture dependent changes in ventilation distribution were properly detected by EIT. Chest sounds were recorded in all subjects. Detection of audible heart sounds was feasible in 44%-67% of the subjects, depending on the sensor location. Accelerometry correctly identified the posture in all subjects. The vests were safe and their properties positively rated, thermal and tactile properties achieved the highest scores.Significance.The functionality and safety of the studied wearable multi-sensor vest and the high level of its acceptance by the study participants were confirmed. Availability of personalized vests might further advance its performance by improving the sensor-skin contact.

Performances evaluation of piezoresistive fabric sensors as function of yarn structure.

This work focus on the characterization of piezoresistive fabric sensors, realized with conductive yarns that are similar in term of conductive components, but different only in term of geometry, the yarns have been realized according two different production processes while the sensors have been produced following the same process, fabric structure and same materials. The different geometry of the yarns affects dramatically conductivity and functionality of the sensors in term of sensitivity and hysteresis minimization. This result confirms that the functional components can be engineered during the different phases of the process production; to get new properties and new applications. Small changes at fibers level can be fundamental to improve the properties of the fabric sensors.

Textile piezoresistive sensors for biomechanical variables monitoring.

In this paper is described the study leading to the implementation of two novel classes of textile piezoresistive sensors, for application in the field of post stroke rehabilitation and cardiovascular diseases monitoring. Two different approaches have been used, the first one leading to the realization of knitted transducer fabric to be integrated in bio-clothes for motion activity and respiration monitoring through plethysmography, the other one leading to printed sensing clothes for movement and posture detection. In particular, this work focuses on the optimization of sensors performances in term of sensing properties with the final objective to go towards a mass production.