Transcript 294 Presentation “sensors for phishing” (i.e., your short

Overview of Wireless Sensor Networks
Applications in Medical Care
Presenter: Ahmed Shawki Bayoumi
Agenda
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Main Idea
Main Achievements
Challenges
Related pictures
Innovation
Abstraction
The main idea of using the Wireless Sensor
Networks in Healthcare is improving the quality
of life of patients and doctor-patient efficiency,
where it enables clinicians to monitor patients
remotely and give them timely health
information, reminders, and support – potentially
extending the reach of health care by making it
available anywhere, anytime.
Overview of Medical Applications
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Utilization of different assets independent of their geographical location
Multidisciplinary collaboration
Facilitates the dissemination of medical knowledge to practicing doctors and medical students
Allows doctors in remote and rural areas to consult with specialists in urban areas
Specialist
Researcher
Patient
Doctor
Stage Model of the Medical Practice
 New and better medical devices
are continuously introduced to
detect vital signals and present
them in a suitable format for
healthcare givers
 The interpretation can be
regarded as a data compression
and data conformity process
 The physicians make a treatment
prescription based on the
patient’s medical history and
current clinical reports by
consulting the evidence-based
database, pharmaceutical
handbook and other resources
Healthcare Wireless Network Expansion
 Each day more and more
equipment is going “wireless”
from pulse-oximeters to more
complex patient vital signs
monitors and ventilators
 Environments must scale from
a few clients to 100’s on a
single subnet
 External factors such as
nearby TV and radio stations
can affect overall
performance.
 Interoperability profiles and
standards are required to
ensure plug-and-play
operation in heterogeneous
environments
WSN Topology
Medical information collected
by sensors on the patient’s
body (WPAN) is displayed on a
bedside monitor
This information is also
transmitted to another hospital
location for remote monitoring,
e.g., a nurses’ station)
In case of emergency, when
the patient is moved from
his/her room to the intensive
care unit, these
communications need to be
maintained
Radio frequency identification
 Facilitates the management of assets (wheel chairs, scanners, ambulatory equipment, etc)
 Improves patient localization and helps caregivers to provide services without delays
 Enhances the process of drug administration (identification, distribution, localization, returns and disposal)
 Facilitates the automatic data capture and the follow-up of blood and biological samples
Mobile reader
Pharmaceutical
product
management
Access
point
RFID
Server
Wallmounted
reader
Medical and chirurgical
equipment tracking
Bracelet
Fixed reader
Patient Identification
and tracking
Equipment localization
and tracking
Agenda
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Main Idea
Main Achievements
Challenges
Related pictures
Innovation
Remote monitoring
 Reduce the number of patients transferred to urban hospitals
 Allows tele-consultation and tele-diagnosis including the option of obtaining opinions of distant experts
 Facilitates the patient remote monitoring with instantaneous data transmission for analyses and follow-ups
 Allows remote handling of medical equipment (tele-surgery) and direct action of the expert on the patient
 Improves coordination of first-responders workers during in the event of catastrophes or emergency cases
Mobile monitoring
platform
Data capture
Mobile device
GSM
GPRS
WiMax
Internet
Real-time patient
monitoring
Wireless Body Area Network
Wireless Body Area Network
The personal server can be implemented on an Internet-enabled PDA or
a 3G mobile phone, or a regular laptop of desktop computer. It can
communicate with remote upper-level services in a hierarchical type
architecture. Its tasks include:
 Initialization, configuration, and synchronization of WBAN nodes
 Control and monitor operation of WBAN nodes
 Collection of sensor readings from physiological sensors
 Processing and integration of data from the sensors
 Secure communication with remote healthcare provider
Mobile Devices
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Facilitates the mobility of doctors, practitioners and caregivers
Allows access to patient information at any moment, everywhere and on real time
Improves automatic data gathering through barcode or RFID reading
Allows the immediate sharing of patient information and results
Improves the internal communication within the caregiver team and with the support staff
Helps to reduce paper
Wired network
Cellular
phones
Laptop
Hospital
systems
PACS
Radiology
Lab
Pharmacy
Etc.
Patient
record
Computer on
wheels
PDA
(Personnel digital assistant)
Tablet PC
Wireless router
(Wi-Fi)
Wearable Monitoring Systems
Fabric electrodes have been used
to monitor EKG and respiratory
activity
Framework for Medical Image Analysis
The remote medical image repositories communicate through different types of
network connections with the central computing site that coordinates the distributed
analysis.
DICOM
The Digital Imaging and Communications in Medicine (DICOM) standard is created
by the National Electrical Manufacturers Association (NEMA) to aid the distribution
and viewing of medical images. DICOM is the most common standard for receiving
scans from a hospital.
A single DICOM file contains both a
header (which stores information about
the patient’s name, the type of scan,
image dimensions, etc), and all of the
image data
DICOM images can be compressed
both by the common lossy JPEG
compression scheme as well as a
lossless JPEG scheme
A single 500-slice MRI can produce a
68 MB image file
Activity Sensors
 They can be useful in monitoring patients
undergoing physical rehabilitation such
as after a stroke
 The Pluto custom wearable designed at
Harvard incorporates the TI MSP430
microprocessor and ChipCon CC 2420
radio
 Pluto can run continuously for almost 5
hours on a rechargeable 120 mAh lithium
battery
 It has a Mini-B USB connector for
programming and to recharge the battery
 The software runs under TinyOS
Pulse Oximeter
 Non-invasive technology used to measure the heart rate
(HR) and blood oxygen saturation (SpO2)
 The technology used is to project infrared and near-infrared
light through blood vessels near the skin
 By detecting the amount of light absorbed by hemoglobin in
the blood at two different wavelengths the level of oxygen
can be measured
 The heart rate can also be measured since blood vessels
contract and expand with the patient’s pulse which affects
the pattern of light absorbed over time
 Computation of HR and SpO2 from the light transmission
waveforms can be performed using standard DSP
algorithms
Pulse Oximeter
 Smiths Micro Power Oximeter Board
 Length: 39 mm
Width: 20 mm
Height: 5.6 mm
 6.6 mA at 3.3 V, typical power:22 mW
 Pulse range: 30-254 bpm
SpO2: 0 to 99%
 Data is transmitted from the oximeter
board at a rate of 60 packets per
second (5 bytes per packet)
 Minolta Pulsox-2
 Size: W69xH60xD28 mm
 Weight: approx. 70g (with 2 AAA
batteries)
Electrocardiograph (EKG)
 The most common type of EKG involves the connection of
several leads to a patient’s chest, arms, and leg via
adhesive foam pads. The device records a short sampling,
e.g. 30 seconds, of the heart’s electric activity between
different pairs of electrodes
 When there is need to detect intermittent cardiac conditions
a continuous EKG measurement is used. This involve the
use of a two- or three-electrode EKG to evaluate the
patient’s cardiac activity for an extended period
 The EKG signal is small (~ 1mV peak-to-peak). Before the
signal is digitized it has to be amplified (gain > 1000) using
low noise amplifiers and filtered to remove noise
Electrocardiograph
 The P wave is associated with the contractions of the atria (the two
chambers in the heart that receive blood from outside)
 The QRS is a series of waves associated with ventricular contractions
(the ventricles are the two major pumping chambers in the heart)
 The T and U waves follow the ventricular contractions
Electrocardiograph
 IMEC has recently developed a wireless,
flexible, stretchable EKG patch for
continuous cardiac monitoring
 Placed on the arm or on the leg the same
system can be used to monitor muscle
activity (EMG)
 The patch includes a microprocessor, a 2.4
GHz radio link and a miniaturized
rechargeable lithium-ion battery
 The total size is 60x20 mm2
 Data is sampled between 250 and 1000 Hz
an continuously transmitted
 The battery has a capacity of 175 mAh
which provides for continuous monitoring
from one day to several days
Agenda
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Main Idea
Main Achievements
Challenges
Related pictures
Innovation
Critical Development Areas
1. Enabling Technologies for Future Medical Devices
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iii.
iv.
Interoperability
Real-time data acquisition and analysis
Reliability and robustness
New node architectures
2. Embedded, Real-Time, Networked System Infrastructures
i. Patient and object tracking
ii. Communication amid obstructions and interference
iii. Multi-modal collaboration and energy conservation
iv. Multi-tiered data management
3. Medical Practice-Driven Models and Requirements
i. Records and data privacy and security
ii. Role-based access control and delegation in real-time
iii. Unobtrusive operation
Critical Development Areas Cont.
Interoperability:
There is need for intercommunication among medical devices and clinical
information systems. This has been accomplished with a number of medical
products. Infusion pumps and ventilators commonly have RS-232 ports, and these
devices can communicate with many physiological monitoring instruments.
Products to link medical equipment
and personal communication
devices exist as well
However, virtually all of these are
specialized applications—custom
interfaces unique to the two
devices being linked
To address the medical device
plug-and-play interoperability
problem, a single communications
standard is needed.
Critical Development Areas Cont.
Real-time data acquisition and analysis:
The rate of collection of data is higher in this type of network than in many
environmental studies. Efficient communication and processing will be essential.
Event ordering, time-stamping, synchronization, and quick response in emergency
situations will all be required.
Reliability and robustness:
Sensors and other devices must operate with enough reliability to yield highconfidence data suitable for medical diagnosis and treatment. Since the network will
not be maintained in a controlled environment, devices must be robust.
New node architectures:
The integration of different types of sensors, RFID tags, and back-channel long-haul
networks may necessitate new and modular node architectures.
Critical Development Areas Cont.
Patient and object tracking:
Tracking can be considered at three levels: symbolic (e.g., Room 136 or X-Ray
Lab); geographical (GPS coordinates of a patient on an assisted living campus);
relational/associational . It is complicated by the presence of multiple patients, nonpatient family members, and leaving the range of the home network.
Communication amid obstructions and interference:
In-building operation has more multi-path interference due to walls and other
obstructions, breaking down the correlation between distance and connectivity even
further. Unwanted emissions and latching are likely to be rigorously restricted and
even monitored due to safety concerns, particularly around traditional life-critical
medical equipment.
Critical Development Areas Cont.
Multi-modal collaboration and energy conservation:
Limited computational and radio communication capabilities require collaborative
algorithms with energy-aware communication. Richly varied data will need to be
correlated, mined, and altered. Heterogeneous devices will be on very different
duty-cycles, from always-on wired-power units to tiny, stealthy, wearable units,
making rendezvous for communication more difficult.
Multi-tiered data management:
Data may be aggregated and mined at multiple levels, from simple on-body filtering
to cross-correlation and history compression in network storage nodes. Embedded
real-time databases store data of interest and allow providers to query them.
Critical Development Areas Cont.
Records and data privacy and security:
Data collected by the network is sensitive, and ownership issues are not always
clear. It is likely that the healthcare provider owns the sensor and network devices,
yet the data pertain to the patient. Data must be available during emergencies, but
access should leave a non-reputable “trail," so abuses can be detected. Any priorityoverride mechanisms must be carefully designed. One may want to filter out
“privacy-contaminated” data, for example, a patient walks into the wrong room. The
system should not “leak” this information through sensors being monitored in the
room.
Role-based access control and delegation in real-time:
Doctors may delegate access privileges to other doctors and nurses; family
members may monitor quality-of-care for nursing home residents. The system may
have DRM-like issues: “read but not copy,” “view but not save," etc. Also, patients
may have read but not write privileges for the collected sensor data, in order to
avoid fraud.
Critical Development Areas Cont.
Unobtrusive operation:
Stealth ness is desirable, particularly for in-home and nursing home applications,
where intrusive technology may not be tolerated. “Invisible” sensors are both
socially more acceptable (draw less attention, more dignified) and more dangerous
(unwanted tagging and surveillance).
Agenda
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Main Idea
Main Achievements
Challenges
Related pictures
Innovation
Some Healthcare WSN Equipments
Healthcare WSN Equipments
Places
Healthcare WSN Infrastructure
Agenda
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Main Idea
Main Achievements
Challenges
Related pictures
Innovation
HL7
 Health Level 7 (HL7) standard is
designed to enable different
health care applications to
exchange clinical and
administrative data
 The most recent version of the
HL7 specification uses XML
messaging as its foundation
 HL7 also allows the use of
trigger events, i.e. when a
patient’s EKG waveform is
available causes a request for
that observation data to be sent
to another information system
Activity Sensors
 They can be useful in monitoring patients
undergoing physical rehabilitation such
as after a stroke
 The Pluto custom wearable designed at
Harvard incorporates the TI MSP430
microprocessor and ChipCon CC 2420
radio
 Pluto can run continuously for almost 5
hours on a rechargeable 120 mAh lithium
battery
 It has a Mini-B USB connector for
programming and to recharge the battery
 The software runs under TinyOS
Wireless Body Area Network
Wearable Monitoring Systems
Fabric electrodes have been used
to monitor EKG and respiratory
activity
Clinical Data vs Wireless Technologies
Biomedical Data
Type
Typical File Size
EKG recording
Electrical signal
100 kB
Electronic Stethoscope
Audio
100 kB
X-Ray
Still image
1 MB
30s of ultrasound image
Moving image
10 MB
Technology
Data Rate
Frequency Spectrum
GSM
9.6 kbps
900/1800/1900 MHz
GPRS
171.2 kbps
900/1800/1900 MHz
EDGE
384 kbps
900/1800/1900 MHz
3G/UMTS
2 Mbps
1885 MHz – 2200 Mhz