Transcript Project HyDRRA Poster - Vanderbilt University

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
User Interface & Data Transfer
Problem Statement
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.
Main Menu
Normal Hydration
Clinical Study Design
Hyperhydrated
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.
Needs Assessment
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
Design: HyDRRA
Hydration Determination by Resistance and Reactance
Analysis
A
Figure 2. BIVA device developed by
Dr. Baudenbacher
•
•
•
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
1.
Display
hydration
status on
Android
Device
2.
3.
Figure 4. Process flowchart outlining the function of the device
Comparison to Competitor
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
•
•
•
•
Figure 5. Bodystat and
BIVA devices
•
4.
5.
6.
Our design
Sleek design
Mobile interface
Wireless data transfer
and cloud storage
More accurate
measurements
Patient data records
7.
Market
Bioimpedance Vector Analysis (BIVA)
Device
Digital multifrequency impedance
spectrometer
Frequency scanning range: 5-200 kHz
Wireless data transfer via Bluetooth
4 Lead Setup: Current source / Voltage
measurement
Percent Difference (%)
Figure 1. The body can be modeled as an
electrical circuit
BIVA
BodyStat
20
15
10
5
0
0
50
100
150
Frequency (kHz)
200
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)
4
3.5
3
2.5
2
1.5
1
0.5
0
ATHLETIC
Long-Term Care
MEDICAL
MEDICAL
Mid
Overhydration
After
Overhydration
Before
Dehydration
100
200
Frequency (kHz)
MEDICAL
EMT and ER
Triage
Endurance Sports
Before
Overhydration
0
Race Participant
Triage
Personal Monitor
Preliminary Results
25
ATHLETIC
COMMERCIAL
Hydration Monitor
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
BIVA Device
•
Set up
device and
place
electrodes
Impedance Difference
(Ohms)
• 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
Figure 3. GUI for an improved Android application. Main menu (Left), healthy results (Center),
and hyperhydrated results (Right) are shown.
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
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
Transthoracic
devices
Repeat step 4 after dialysis treatment
Remove electrodes and collect post-treatment
weight
Record total volume of fluid lost during treatment
After
Dehydration
Figure 9. Bowling pin diagram for market capture. Courtesy of Anna Rose Kelsoe.
Conclusions & Future Steps
•
•
•
•
Acknowledgments
Special thanks to Matthew Walker III ,PhD; Kevin Sexton, MD; Franz
Baudenbacher, PhD; James Pietsch, MD; Tracy Perry, and René Harder
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
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
Completed
Future
Established detection sensitivity • Determine indicative test
Designed and submitted clinical
frequencies and electrode
IRB study
placement regimes
Designed GUI for Android
• Develop hydration status
application
algorithm based on study results
Comparison with competitor
• Code Android application
References
1.
2.
3.
4.
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. 2008. The Gale Group, Inc. 8 Apr. 2014 http://medicaldictionary.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 101.10 (2012): e479-e481.