Scott T. Mazar

Estimation of patient compliance in application of adherent mobile cardiac telemetry device

In an in home usage outpatient setting, patient compliance is a key factor in determining the adoption and efficacy of treatment for any illness and is paramount for patient dependent medical technologies such as mobile patient monitoring systems. As a leader in the development of these technologies, Corventis has deployed its NUVANT™ Mobile Cardiac Telemetry System to thousands of patients around the world. The NUVANT system includes an externally worn adherent sensing device, the PiiX, whose proper application is critical to the on-patient longevity and thus performance of the NUVANT system. Patient compliance in this context is a universal challenge for such patient-applied adherent devices. Understanding and tracking a problem is key to solving it and the integrated suite of vital sign sensors in the Corventis PiiX offers a unique opportunity for extracting patient application compliance information from the incoming health data. Analysis of data from 5000 randomly selected patients has shown that improper application of the PiiX is a factor in 2.3% of patients. However, no reduction in adherent device longevity or performance was observed. Such information is a valuable feedback metric for product design, instructions for use, packaging of medical technologies, level of customer support and replacement costs.

Modeling the effects of biological tissue on RF propagation from a wrist-worn device.

Many wireless devices in common use today are worn either on or in close proximity to the body. Among them are a growing number of wrist-mounted devices designed for applications such as activity or vital-signs monitoring, typically using Bluetooth technology to communicate with external devices. Here, we use a tissue-mimicking phantom material in conjunction with anechoic chamber and network analyzer testing to investigate how antenna propagation patterns in one such device are influenced by the electrical properties of the human wrist. A microstrip antenna module is mounted onto phantom material of various geometries, and the resulting voltage standing wave ratio (VSWR), input impedance, and azimuth radiation pattern are recorded in both free space and real-world environments. The results of this study demonstrate how the high permittivity values of human tissue (εr ≈ 16) affect the design parameters of microstrip antennas. A simulation environment using Sonnet EM software was used to further analyze the high dielectric effects of biological tissue on RF propagation.