Pulmonary Edema Monitoring Sensor With Integrated Body-Area Network for Remote Medical Sensing

A wearable health monitoring sensor integrated with a body-area network is presented for the diagnosis of pulmonary edema. This sensor is composed of 17 electrodes with 16 ports in-between and is intended to be placed on the human chest to detect lung irregularities by measuring the lung´s average dielectric permittivity in a non-invasive way. Specifically, the sensor´s active port is fed by a 40 MHz RF signal and its passive ports measure the corresponding amplitudes of the scattering parameters (S-parameters). The dielectric constant of the lung is then post-processed and expressed as a weighted sum of the S-parameters measured from each port. An important aspect of the sensor is the use of multiple electrodes which mitigates the effect of the outer layers (skin, fat and muscle) on the lung´s permittivity. This allows for the characterization of deeper tissue layers. To validate the sensor, tissue-emulating gels were employed to mimic in-vivo tissues. Measurements of the lung´s permittivity in both healthy and pulmonary edema states are carried out to validate the sensor´s efficacy. Using the proposed post processing technique, the calculated permittivity of the lung from the measured S-parameters demonstrated error less than 11% compared to the direct measured value. Concurrently, a medical sensing body-area network (MS-BAN) is also employed to provide for remote data transfer. Measured results via the MS-BAN are well matched to those obtained by direct measurement. Thus, the MS-BAN enables the proposed sensor with continuous and robust remote sensing capability.