Accessible Home Vital Signs Monitoring System

1
Accessible Home Vital Signs Monitoring System
Brett Chung, Ashraf Fawzy, Maggie Jan, Jordan
Muraskin Department of Biomedical Engineering,
Columbia University, NY, NY
Introduction
Problem
Proposed Solution
VitalSense Systems offers an unobtrusive wearable
device to continuously monitor the four most
indicative vital signs blood pressure, pulse,
oxygen saturation, and body temperature. Allowing
the physician to monitor these vital signs
prevents complications in patients with
pre-diagnosed ailments. The system consists of
wearable and portable networked devices that are
controlled wirelessly using Bluetooth technology.
An on-body computing device acquires, analyzes,
and transmits data securely and wirelessly in
real-time to a healthcare provider who is alerted
to the patient condition.
Currently, there exists an array of home vital
sign monitors, however these devices are neither
accessible to the physically disabled nor capable
of simultaneous data acquisition in the home
environment. With the rising cost of healthcare,
it is imperative to develop methods for simple
and safe patient home-monitoring. The use of
remote health-monitoring has the potential to
decrease the length of hospital visits and the
incidence of unnecessary emergency room visits.
Fig 1. Diagram of VitalSense System Architecture
System Requirements Allowing Accessible
Health-Monitoring
System Components
Importance of On-Board Analysis User Input
Basic Device Features

• Increases accuracy of diagnosis
• Allows for explanation of abnormal data
• Queries user for additional data for analysis
• Increases system efficiency
• Reduces un-necessary power and bandwidth by
  controlling when sensors are turned on
• Send only relevant information
• Alerts patient when to use wearable equipment
• Eliminates complicated commands through
  automation and interface
• Increases health awareness by including the user
  in the health-monitoring process
• Multiple data output formats such as voice
  synthesis increase accessibility

• Wireless and wearable system
• Acquire vital signs data from medical sensors
• Display data to user

• Perform preliminary on-board data analysis
• Allow user customization
• Prompt and alert user
• Acquire user input

• Wearable Medical Sensor Devices (Blood Pressure
  Cuff, Pulse Oximeter, and Temperature Sensor)
• HP iPAQ PDA with Wireless Capabilities (802.11
  Wi-Fi Standard Bluetooth Protocol)
• Bluetooth Transmission Modules

System Limitations
Why Bluetooth?

• By incorporating the use of wireless technology,
  patients can experience maximum comfort and a
  free range of movement, while having their vital
  signs accurately assessed. In addition, Bluetooth
  technology addresses efficiency and security
  concerns
• Low power, high compatibility, and cost-effective
• Bluetooth allows the device to be portable,
  reduces the number of wires, facilitates patient
  comfort
• Fast, encrypted, and reliable data transmission
• Short-range wireless communications system thus
  minimizing conflict with other enabled devices

• Limited memory capacity (190 MB) on the HP iPAQ
  PDA
• All web interface scripts must be compatible with
  Windows Mobile 5.0-based version of Internet
  Explorer for HP iPAQ
• Reduced web server xampp
• Windows Mobile 5.0 does not support Java
  programming
• Limited to RERC National Design
  Competition-specified vital signs parameters
  which restricts diagnostic ability
• Need for system to be wearable and accessible
  limits the size and type of medical sensor

A feedback loop
Fig 2. The wearable device will prompt and query
the user for necessary information.
Product Description The VitalSense System
On-Board Reasoning Graphical User Interface
Medical Sensors

• On-Board AnalysisEquipped with C code, the PDA
  opens serial connections with standard Bluetooth
  Devices, send commands and receives data. Other
  continuously running C programs allow for
  on-board reasoning that continuously analyzes the
  streaming vital signs data.
• Graphical User Interface
• Web forms on the PDA acquire user input and also
  display data trends to the user. Common Gateway
  Interface (CGI) scripts allow data to be sent
  from an HTML form to a server. The wearable PDA
  system runs Perl CGI scripts hosted on a web
  server. These scripts run protocols that range
  from uploading files to the server, generating
  audio output, updating a log of abnormal events,
  and generating Gnuplot graphs for display.

Nonin OEM 4100 Pulse Oximeter

• Continuous stream of HR and SpO2 saturation
• Bluetooth enabled
• Wearable on wrist with finger-tip sensor
• Powered by 2 AA batteries with integrated switch

Fig 3. Nonin Pulse Oximeter with protective casing
Advantage Mini OEM Blood Pressure

• On demand Blood Pressure HR readings
• Serial RS-232 Connection to Parani SD-200
  Bluetooth dongle
• Range 20-260mmHg BP, 30-220 BPM HR
• Calibrated for optimal accuracy
• Abort command for patient safety
• Powered by 2 9-Volt batteries with switch

Fig 4. Blood Pressure Temperature Sensor
Thermometer
Ergonomics

• 96-109 F calibrated range
• 54k thermistor at 25C sensor
• Oral temperature sensor for high accuracy
• Arduino serial analog to digital converter
• Serial RS-232 connection to Parani SD-200
  Bluetooth dongle
• Powered by 1 9-Volt battery with switch

Blood Pressure Module
Temperature Sensor External casing is
durable and waterproof Lightweight
with minimal wires Housed with
BP module

• Blood Pressure Unit Allows for single-
  handed fitting of cuff on arm
  Detachable Unit Shortened hose

Nonin Sp02 Monitor Switch to maximize
battery life External casing is waterproof
and durable Velcro straps to minimize
dangling wires
Temperature Sensor
PDA
Pulse Oximeter
Fig 5. The VitalSense System worn by a patient
Product Development
Testing
Future Applications

• Additional medical sensor modules can be
  incorporated
• Miniturization of wearable devices
• Capability for audio user input
• Replacing PDA with Smartphone for cell phone
  backup communications
• More analytical pathways for medical diagnosis
• Emergency dispatch functions
• Mass implementing for hospital or nursing home
  setting

• BP, SPO2 HR Accuracy tested against Phillips
  IntelliVue MP30 hospital monitor
• All values within range of statistical
  insignificance
• SpO2 accuracy of oxygen saturation values tested
  on all fingers. The little finger shows a
  statistically significant difference.
• Temperature calibrated against Rite Aid 54 kohm
  thermistor digital thermometer
• Ergonomics survey conducted to choose best design
• Ease of use and comfort tested with
  characteristic individuals

Fig 6. Two sample F-test for variances. Showing
no significant difference between hospital
bedside monitors and the VitalSense medical
device.
Fig 7. Calibration curve for temperature sensor.
Analog signal required conversion to a meaningful
temperature value through linear regression.
References
Acknowledgements
This prototype was funded by the RERC on AMI
National Student Design Competition. We would
like to thank GordanaVunjak-Novakovic, Keith
Yager, Elisa Konofagou, Rob Maidhof, David
Vallancourt, Chris Murphy, David H. Newman, Nina
Tandon, David Lariviere, and GainTrack for their
contributions.
UNESCO/Daimler Chrysler Mondialogo Project.
Michigan State University. 1 May 2007
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ing/group04/gt