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HyDRRA Hydration Determination by Resistance & Reactance Analysis

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Presentation on theme: "HyDRRA Hydration Determination by Resistance & Reactance Analysis"— Presentation transcript:

1 HyDRRA Hydration Determination by Resistance & Reactance Analysis
Team Pferck Douglas J. Hall, Cara G. Welker, Mary Morgan Scott, Rachel-Chloe Gibbs, Skylar C. Haws Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA Problem Statement User Interface & Data Transfer Clinical Study Design Main Menu Normal Hydration Hyperhydrated Many clinical disorders correlate with hydration status. However, health care providers have few reliable non-invasive methods for real-time quantification of hydration status in the clinic. Purpose: Correlate impedance changes to fluid volume loss for hydration status algorithm development Experimental Population: Dialysis patients Exclusionary Criteria: Congestive heart failure, diuretics IRB Status: Pending after preliminary review Background Dehydration alone causes 518,000 annual hospitalizations and $5.5 billion in charges 1 Hyperhydration is the most common electrolyte imbalance in hospitals, occurring in about 2% of all patients 2 Current gold standard: Acute hydration measurements are obtained by invasive swan-ganz catheter placement, which is invasive & impractical and requires trained clinicians to use. Wrist to Ankle Figure 8. Dialysis overview Protocol Collect general patient data (height, weight, and age) from nursing staff Sanitize and clean surfaces of skin with rubbing alcohol and cotton wipes for electrode placement Place electrodes in one of the testing configurations (see right) Record impedances using Bodystat and BIVA devices Repeat step 4 after dialysis treatment Remove electrodes and collect post-treatment weight Record total volume of fluid lost during treatment Figure 3. GUI for an improved Android application. Main menu (Left), healthy results (Center), and hyperhydrated results (Right) are shown. Set up device and place electrodes Run determined range of frequencies Impedance correlated to hydration based on established model Voltage change converted to impedance reading Change in voltage measured by device Display hydration status on Android Device Needs Assessment Figure 4. Process flowchart outlining the function of the device The solution must: Correlate diagnostic information to changes in hydration status Assess hydration status in clinical setting without prior background monitoring Allow the provider to easily translate/display data Provide the patient with a noninvasive, unobtrusive and comfortable product Comparison to Competitor Transthoracic Bodystat QuadScan 4000 $3,000 retail Difficult data transfer No patient data storage Inconvenient and slow UI Results not communicated in a clinically relevant way Our design Sleek design Mobile interface Wireless data transfer and cloud storage More accurate measurements Patient data records Market Design: HyDRRA MEDICAL Hydration Monitor EMT and ER Triage ATHLETIC Endurance Sports Long-Term Care Race Participant Triage COMMERCIAL Personal Monitor Hydration Determination by Resistance and Reactance Analysis Figure 5. Bodystat and BIVA devices Human body can be modeled as electrical circuit Capacitive elements are frequency dependent Obtain impedance data at various frequencies Correlate impedance values with hydration status Compare to market competitor Establish improved device and model for clinical prediction of hydration status Preliminary Results Dehydration Protocol (n=8): Subjects exercised without rehydration Overhydration Protocol (n=4): Subjects drank 1/100 of their body weight every hour for 12 hours Figure 9. Bowling pin diagram for market capture. Courtesy of Anna Rose Kelsoe. Conclusions & Future Steps Completed Future Established detection sensitivity Determine indicative test frequencies and electrode placement regimes Designed and submitted clinical IRB study Designed GUI for Android application Develop hydration status algorithm based on study results Comparison with competitor Code Android application Figure 1. The body can be modeled as an electrical circuit BIVA Device Acknowledgments Bioimpedance Vector Analysis (BIVA) Device Digital multifrequency impedance spectrometer Frequency scanning range: kHz Wireless data transfer via Bluetooth 4 Lead Setup: Current source / Voltage measurement Special thanks to Matthew Walker III ,PhD; Kevin Sexton, MD; Franz Baudenbacher, PhD; James Pietsch, MD; Tracy Perry, and René Harder Figure 6. A positive impedance change is seen in both the BIVA and BodyStat over all frequencies after weight loss of at least one pound during workout (n=3) Figure 7. A greater difference is seen between the BIVA and BodyStat devices at more hydrated states, but the difference between the two devices is still relatively small References A Kim, S. "Preventable hospitalizations of dehydration: Implications of inadequate primary health care in the United States." Annals of Epidemiology 17.9 (2007): 736. "Overhydration." Gale Encyclopedia of Medicine The Gale Group, Inc. 8 Apr. 2014 http://medical-dictionary.thefreedictionary.com/overhydration Wang, Zimian, et al. "Hydration of fat-free body mass: new physiological modeling approach." American Journal of Physiology-Endocrinology And Metabolism 276.6 (1999): E995-E1003. Dunkelmann, Lea, et al. "Estimation of dehydration using bioelectric impedance in children with gastroenteritis." Acta Paediatrica  (2012): e479-e481. Problem: It is challenging to reliably induce a quantifiable amount of water loss or overload outside of the clinical setting Solution: Clinical study in an experimental population that undergoes rapid, quantified fluid loss Figure 2. BIVA device developed by Dr. Baudenbacher


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