Continuous weight monitoring for heart failure patients

  • Nisrein R. Sada

Student thesis: Master's Thesis

Abstract

Congestive heart failure (CHF) affects 10% of the population above 65 years and is one of the leading contributors to healthcare costs. One of the main markers for the deterioration of the heath of CHF patients and subsequent hospitalization is edma. Recent studies have shown that edema can be detected from weight increase up to two weeks before hospitalization. Weight measurements have therefore become part of the standard for medical practice. Moreover, the medical literature indicates that this condition is promising for remote monitoring. In this work we explore the use of shoe mounted pressure sensors to measure pressure in the shoe sole in order to automatically and remotely estimate the weight of CHF patients. We conducted a broad experimental study of pressure sensors in an effort to find suitable sensors to use in an insole. Our study has revealed that the pressure sensors widely used in wearable applications exhibit properties that are undesirables for precision weight measurements. Specifically, we have measured and characterized creep, repeatability problems and noise that limit the accuracy of weight estimates. Our experimental study included force sensitive resistors, flexiforce sensors, Velostat, Neoprene, and semi-conductive polymer composite materials. These piezoresistive materials were considered instead of strain gauges that are used in weight scales, due to their flexibility, low cost, comfort and ease of application as insole. Different materials were evaluated for the sensor electrodes and the packaging of the sensor such as copper plates, neoprene and conductive fabrics in order to reduce noise and creep. Two experimental setups were utilized and several test procedures were developed to collect data for the characterization of the sensors. Finally a predicted model is compared to the creep test data.
Date of AwardAug 2015
Original languageAmerican English
SupervisorAyman Shabra (Supervisor)

Keywords

  • Heart Failure
  • Weight Measurement
  • Pressure Sensors
  • Textile Sensors
  • In-Shoe system.

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