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Monitoring and Control of Bodily Fluids for Geriatric Patients

Fig. 1: Change of the Population Structure in Germany.

Fig. 2: Concept for wearable BIS-system.

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Project description

The German society is undergoing a profound change in its age distribution (Fig. 1). According to demographic trends, those over 65 years-old will comprise about a third of the population in the coming 30 years.

Some geriatric patients have difficulties regulating the adequate amount of water in their bodies. Two typical reasons for inadequate water intake are incontinence and a decrease in thirst. Through bioimpedance measurements, the total body fluid content, and subsequent changes thereto, can be evaluated. Here a minute and safe alternating current is passed through the body, whereby the body’s electrical resistance can be gauged. To improve accuracy, the bioimpedance values are obtained at several frequencies. With the help of bioimpedance models, the total body water content can be calculated.


  • Current imprecise bioimpedance models
  • Proper water content of single individual is not yet known
  • Optimal position for the electrodes for mobile application is not yet known
  • Influence of external factors (e.g. body position, temperature)
  • Problematic integration
  • Motion artifacts

Project goals

  1. Development of a wearable system that allows the continuous monitoring of water intake in older patients (Fig. 2).
  2. Through correlating data on water content and health status, the optimal body fluid content can be determined.
  3. Through physiological modeling the influence of external factors can be diminished.
  4. Verification of the bioimpedance fundamentals and their interpretation in order to optimize mobility and reliability.

Project partners


  • G. Medrano, L.Beckmann, N. Zimmermann, T. Grundmann, T. Gries and S. Leonhardt, "Bioimpedance Spectroscopy with textile Electrodes for a continuous Monitoring Application", 4ht International Worskshop on Wearable and Implantable Body Sensor Networks (BSN 2007), Aachen, March 26th-28th, 2007. IFMBE Proc, Volume 13, pp. 23-28.
  • G. Medrano, P. Zhang and S. Leonhardt, "Modeling the Influence of Body Position in Bioimpedance Measurements", Proceedings of the 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society-EMBC 2007, Lyon, France, Aug. 23rd-26th, 2007.
  • G. Medrano, A. Ubl, N. Zimmermann, T. Gries and S. Leonhardt, "Skin Electrode Impedance of Textile Electrodes for Bioimpedance Spectroscopy", 13th International Conference on Electrical Bioimpedance combined with the 8th Conference on Electrical Impedance Tomography (ICEBI 07), Graz University of Technology, Graz, Austria, Aug. 29th-Sep. 2nd, 2007. IFMBE Proceedings, Volume 17, pp. 448-451.