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A smart bed for non-intrusive patient
monitoring W.B. Spillman Jr., M. Mayer, J.
Bennett, J. Gong, K.E. Meissner, B. Davis, R.O.
Claus and A.A. Muelenaer Jr. Virginia Tech
Applied Biosciences Center Virginia Polytechnic
Institute and State University Blacksburg,
Virginia 24061, USA
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Current Methods of Monitoring Patient Vital Signs
Require Direct Connection to Instrumentation
Increased amounts of automation in elder care are
becoming a critical necessity as the world
population ages.
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Sedentary Elderly Become Vulnerable to Extremely
Painful Conditions Due to Lack of Mobility
Sedentary patients in nursing homes require
assisted movement to prevent the occurrence of
pressure induced ulcers (bed sores). If patient
movement can be remotely monitored, optimum
schedules for assisted movement can be
devised. The potential market for such a
capability is in the multi-B range.
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The Smart Bed Concept was Developed in Response
to the Need for Non-Intrusive Automated
Monitoring of Patient Movement and Vital Signs

• A long gauge length integrating fiber optic
  sensor is integrated into a standard patient bed
  beneath the mattress.
• Patient physical movement and movement due to
  respiration and heartbeat perturb the fiber.
• Modulation of the optical signal due to the
  integrated mechanical perturbation of the fiber
  is processed to provide the required information.

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W.B. Spillman et al, Statistical mode sensor for
fiber optic vibration sensing applications,
Applied Optics 28, No. 15, pp. 3166-3176, 1989.
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P.R. Herczfeld et al, An embedded fiber optic
sensor utilizing the modal power distribution
technique, J. Opt. Lett. 15, No. 21, pp.
1242-1244, 1990.
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The Absolute Value Processing in the STM Sensor
Distorts the Power Spectrum and Low Frequency
Signals Mask Higher Frequency Signals
HOME sensor
STM sensor
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Undergraduate Students Took Part in the Research
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The STM Sensor Demonstrated the Ability to Detect
Patient Movement and Respiration Rate
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The HOME Sensor Demonstrated the Ability to
Detect Patient Movement, Respiration Rate and
Heart Rate
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The Enabling Technologies for the Smart Bed
Concept are Low Cost Computers and Wireless
Digital Cameras
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The System Uses Cost Effective Off-the-Shelf
Hardware
nurse wearing RF ID tag
STM sensor
data is processed and activity is logged by a
central computer at the nurses station
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Minimal Engineering Development was Required to
Create the Wireless System
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Continuing Refinement of the System is Taking
Place

• Human body motion on beds is being modeled to
  allow the spatial configuration of the sensing
  fiber for optimal sensitivity to the parameters
  of interest (matched filtering) to be determined.
• A clinical trial of a simple one bed STM system
  will be carried out in the very near future at
  the Carilion Health System Sleep Center in
  Roanoke Virginia.
• A 6 bed multiplexed system is in the process of
  being designed and fabricated. It will be
  clinically tested within the next 6 months at a
  Medical Facilities of America nursing home in
  Roanoke Virginia. Care is being taken to insure
  that the system is compatible with existing
  systems already being used.

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A Proof of Principle for Non-Intrusive Patient
Monitoring has been Carried Out

• The ability to detect patient movement,
  respiration rate and heart rate has been
  demonstrated.
• Two different fiber optic sensing techniques
  were investigated and compared.
• A wireless version of the concept has been
  developed using off-the-shelf cost effective
  components.
• Clinical trials of the concept will take place
  in the very near future.
• Work to refine and improve the technology
  involved is on-going.