Medical Applications of Wireless Networks
Dr. Shobha G
Assistant Professor, Dept. of C.S.E, R.V.C.E, Bangalore
shobhatilak@rediffmail.com
Ranjana R.Chittal
M.Tech(C.S.E), Dept. of C.S.E, R.V.C.E, Bangalore
Kamod Kumar
M.Tech(C.N.E), Dept. of C.S.E, R.V.C.E, Bangalore
ranjana_chittal@yahoo.com
Abstract
Sensor based technology has invaded the medical
devices with a wide range of devices available today
with wireless network capability, which have the
potential to replace thousands of wires connected to
devices found in the hospitals. This technology has the
capability of providing the reliability with enhanced
mobility. It is being looked upon as alternative solution
to provide low cost medical solution along with
enhanced accessibility to the patients in view of
permanent usage of wireless devices.
In this survey paper background of applications of
wireless networks in the medical field and the issues
and challenges involved in this technology
transforming lives of several people who are deprived
of quality health care facilities are discussed. Finally
architecture for this communication system is
discussed.
Keywords: wireless medical applications, architecture
for medical wireless network, issues & challenges
1. Introduction
Wireless sensor network[1] is an emerging
technology consisting of small, low-power, and lowcost devices that integrate limited computation,
sensing, and radio communication capabilities.
Minimal configuration and quick deployment make adhoc networks suitable for emergency situations like
natural or human-induced disasters, military conflicts,
emergency medical situations etc. This is a promising
technology which can improve the healthcare industry
and it is finding its way into various aspects of our life.
Sensor devices can be used to capture continuous
data from patients in real time and communicate to
doctors & Emergency Medical Technician staff
(Nurses & Technicians) on their hand held devices.
This technology can prove vital in mass casualties and
natural disaster where patients’ records like
identification, previous medication history and other
kamodkumar@gmail.com
vital information can be stored. This technology is
expected to reduce the amount of time the doctors
require to identify the problem and consult fellow
doctors through use of hand held devices
communicating in ad hoc mode. Also this will reduce
the amount of paper work required and the duplication
of patient records.
Ad hoc network facilitates creation of
network of medical devices on the fly (Sensor
network) thereby supplementing the resources at hand
by providing features like reconfiguration and
reallocation similar to HAM radios in use today. The
devices use minimal power and are robust which
decrease their dependence on available infrastructure
(resources like electricity supply, communication
infrastructure like telephone lines etc which are target
of insurgents or are destroyed by natural disaster) and
this makes them an attractive alternative.
However this technology has a limitation as the
ranges of these devices are fixed and to enable the
services to be extended to large geographical areas like
ambulances and patient premises requires this
infrastructure to interoperate with other wireless
networks like GSM /CDMA mobile networks. Thus,
we are looking at a new technology which is born as a
result of fusion of medical sensors and mobile
technology.
This technology promises to reduce the number
of visits required by patients for health checkup by
allowing the doctors to remotely monitor the patients
and advice them. Life insurance companies can collect
the data from the database to settle the medical claims.
With all this discussion of wireless applications,
healthcare providers such as hospitals, insurance
agencies and the government are becoming interested
in investing in this area. Cost saving is one of the main
factors because medical errors by doctors bring in law
suits and patient and hospital management and be very
expensive too. This has drawn a lot of attention of both
researchers and industry.
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This survey starts with a discussion on wireless
technology and then looks into the proposed
architecture. Then the various challenges and future
trends are explored.
2. Wireless Technology
In order to avoid contamination most of the
hospitals ban entry of unrelated items including people
in the critical wards and Intensive Care Unit. This is
primarily done to avoid contamination and infection.
One aspect which is not taken care of in this regard is
the contamination caused by the use of large number of
cables running in these rooms and interconnecting the
devices. It is neither possible to remove these wires nor
avoid them from coming in contact with patients. A
suitable alternative to this problem is to make these
devices communicate without wires through wireless
communication.
Wireless communication has evolved over the
period of time such that it is now capable of providing
high data rates & reliability for short ranges.
Technologies like Bluetooth [2], PAN and WLAN
have already proved their might and are widely in use
today.
Research is also carried on creating mobile trauma
systems using the wireless channel. This will
potentially allow trauma specialist to be virtually on
patients’ bed sides while they are being moved to the
trauma centre. Another issue that concerns the
healthcare field is the large number of tedious routines
that are involved in translating results from one
machine to another which are expensive as well as
incompatible with each other. With Wireless
Technology this compatibility issue can be reduced
There is a new facet of this technology that has
emerged in the last few years. This issue is related with
the wearable wireless implants that the patients can be
fitted with and these can collect the data through their
sensors and relay this data to the hospital through
wireless communication. This technology will address
the issues regarding the access wherein patients need
no longer move around the hospitals for regular
checkups.
3. Potential Medical Applications
All the applications of wireless networks can be
broadly classified as follows[a] Real Time Continuous Patient Monitoring
⇒ Pre hospital, In hospital and ambulatory
monitoring.
These applications are basically concerned with the
monitoring of vital signs and recording the various
statistics of the patients. They can be thought of as a
simple replacement of wired medical equipment like
ECG, etc.
[b] Home monitoring for Chronic and Elderly
Patients
⇒ Collect periodic and continuous data and
upload it to the doctors
⇒ Allow long term care and trend analysis &
most importantly reduce the hospital stay.
All these applications are designed with the
intension to reduce the stay of patients in the hospitals
except for the time required for procedures. This
facilitates the physicians to monitor several patients
virtually in the same time which could not be achieved
if patients are hospitalized.
[c] Collection of long-term databases of clinical
data
⇒ Correlation of Bio sensor reading with other
patients’ information
⇒ Longitudinal studies across the populations
and incorporation of study effects of
interventions and Data Mining.
These applications are basically concerned with the
study of epidemic and issues relating community
health.
The most important use of such a network would be
in case of large accidents, fire or natural disasters like
floods or terrorist attacks. In all these scenarios the
normal community services may be damaged or
destroyed leaving a large number of patients which can
cause severe load for the emergency personnel
attending the casualties. Since the core communication
infrastructure is completely destroyed or damaged and
or because of large number of casualties the only way
of tracking them is through papers and reports with
manual identification of each of them.
The sensor networks concatenated with other
wireless technologies have the potential to affect the
large number of casualties by providing a means of real
time continuous monitoring of vital systems of
patients. Each patient is provided with a tag for his/her
identification which can be used to identify him/her
and study his/her previous medications. The
emergency staff has the provision to keep a watch on
the patients who require immediate attention upon
receiving alerts from changes in the health status. This
can also be relayed back to the hospital where the
patients are being moved so that the doctors have the
opportunity to correlate the data and identify the
procedures for the patient.
4. Architecture and Services
The architecture of Sensornet based wireless
medical [1] device consists of an information plane
which provides coordination and communication
across the wireless medical devices. The
communication model comprises of Publisher-
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Subscriber data delivery model where the sensor nodes
publish vital signs, location information, its identity
etc. Rescue personnel and others can subscribe to this
information depending on the area of interest and
receive the subscribed information.
provide for reliable transmission of critical data
through content-specific prioritization and dynamic
scaling of transmission power.
Fig 1 shows the proposed architecture which is an
extension of the architecture proposed for codeblue
[1].The extension comes in the form of a Convergence
Layer similar in functionality to the IMS [3]. The
requirement that this architecture addresses to is the
communication between the various devices through
the other wireless technology which allows PDA’s,
Mobile Phones (Smart Phone) and other hand held
devices. This design allows diversified architecture to
combine to provide communication with Medical
Sensornets.
Another issue that is addressed by this architecture
is providing a mechanism for high data communication
which would enable doctors to provide prescription &
consulting along with real time monitoring the patients
There are various protocols which are used in this
architecture to enable reliable communication of data.
Protocols address the issues like addressing-naming,
Authentication – Encryption, Event delivery, FilteringAggregation, Handoff- Hard/Soft, etc.
There are a number of issues that are identified in
this survey so as to make the technology acceptable for
medical applications [4]. The prime objective of course
is to develop a wireless solution which can be reliable
and fault tolerant. The research areas can be classified
as explained under [a].[b] & [c] as follows:
Naming
Discovery
Information Plane
Event
Filtering
Delivery
Traffic
Authentication
–Encryption
Handoff
Aggregation
Convergence Plane
Fig1. Proposed Communication Architecture-Convergence of
Technologies
The use of ad hoc networking will allow the “mesh”
of connectivity to extend across an entire building or
between multiple, adjacent facilities. Additional
coverage, if necessary, will be possible with placement
of fixed nodes in hallways, rooms, or other areas. No
matter the topology, the network will be selforganizing: loss of a given node or network link can be
rapidly detected and data re-routed accordingly. It can
5. Research Challenges
[a] Communication Challenges
The first and foremost issue is to provide a
mechanism for secure and reliable communication
among the various groups of sensors, handheld devices
& mobile. Sensor networks are self organizing and
operate with low power and very little computational
resources. There is a limit on the type and complexity
of application data that these devices can operate on.
Second issue is the prioritization of critical data which
require immediate attention of medical professional.
Convergence of communication architecture and
security issues with regard to various devices is equally
important. Since these devices work with short range
transmitter and receiver, a method needs to be devised
for making sensor networks utilize the available
GSM/CDMA infrastructure to enable communication
between two peers separated by large distance.
[b] Computational Challenge:
Sensor nodes have very limited computational
power, and traditional security and encryption
techniques are not well-suited to this domain. While
secret-key cryptographic systems have been
demonstrated on motes, there is currently no practical
means of establishing encryption keys. The use of
efficient, integer-based elliptic curve cryptography is
explored which has the potential to allow rapid
rekeying among groups of sensors. The system must
allow physicians, nurses, and others to assign access
rights to patient data quickly and determine handoff
credentials when a patient is transferred to another unit
or hospital. Existing authentication systems are
extremely rigid in this regard.
[c] Programming Challenge
Finally, coordination of a diverse array of sensors,
active tags, handheld computers, and fixed terminals
requires a cohesive communication and programming
model to underlie the system’s operation. Existing
software for sensor nodes is in a very low-level and
does not provide higher-level services such as
discovery, naming, security and data delivery within a
common framework. Our goal is to develop a flexible
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protocol suite for integrating a range of wireless
devices in a critical care setting.
Some main issues that arise due to the use of wireless
networks devices include security, privacy and the
learning curve for new technologies. Ensuring patients
information security can be a major issue when
deploying these applications. Privacy of user data over
wireless channels can be another major issue. Wireless
networks based medical devices can be very limited in
terms of power availability and processing strength.
Thus ensuring privacy without using complex
encryption algorithms can be a big issue for developers
of medical devices. With the new technologies
pervading in our daily lives, new users can find it
challenging to use these new devices to the fullest.
Thus it can be an issue and a challenge for developers
to create some of the best solutions without forcing the
users to make unnecessary of effort just to learn how to
use them.
being developed in the research community for the
purpose of healthcare improvements. Some these
medical applications have impacts in daily social life,
while others have pure medical benefits. A list of other
applications can be found in the manufactures websites
[5-7]
7.1 Code Blue
CodeBlue [8] is a sensor network based medical
research project being developed at Harvard. Specific
goals for this project include pre-hospital care and inhospital emergency care, stroke patient rehabilitation
and disaster response. Research from this project has
potentials for resuscitative care, real-time triage
decisions and long term patient observations.
This project has hardware as well as software
parts. Fig 2 shows a Mote based pulse oximeter which
is a Wireless Vital Sign Sensor which forms a part of
hardware.
6. Standards
Although the area of wireless networks for
medical applications is largely without standards due to
companies developing products based on their own
standards, there do exist some standards and the same
have been listed a few below.
Recently, the demand for creating strict standards,
especially for pacemakers, which are being used by a
large number of heart patients across America, has
increased.
•
IEEE
Standards
Medical
Device
Communications / Health Informatics
Standards Subscription
o
ISO/IEEE Health informatics Point-of-care
medical
device
communication
o
IEEE Standard for Medical Device
Communications-Transport Profile
•
Mobile Health Care Alliance
o Setting standards for mobile health
information systems
•
Medical Implant Communications Service in
the 402-405 MHz band
o High-speed, ultra-low power, nonvoice transmissions to and from
implanted medical devices such as
Cardiac
pacemakers
and
defibrillators.
7. Research Applications
This section discusses about some special
applications that have been developed or are currently
Fig2. Mote-based pulse oximeter.
Some devices and software produced in the project
include
* Wireless Vital Sign Sensors
* Wireless two-lead EKG [Jones04]
7.2 Project Connect
The Connect project [9] is basically focusing
on creating solutions to help people with disabilities in
their day-to-day life. They are trying to create a
distributed wireless communication infrastructure that
allows for individual customization of portable devices
such as a PDA. Initially the project relied on GPRS for
communication between the PDA devices and the
central server. The main aim of the project is to enable
people with disabilities to customize their wireless
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devices i.e PDA to keep schedules for them, give them
important reminders and allow them to communicate
with their caregivers through any of the several
possible ways provided. Therefore this system adapts
to the user's needs.
7.3. Industrial Applications
7.3.1 LifeSync Wireless ECG System
Fig3 : Wireless ECG Transceiver
LifeSync [10] Wireless ECG System is a
basic ECG device that operates using Bluetooth
wireless technology. It can collect patient ECG and
respiratory data and transmit using two-way radios. Fig
3 shows a set of transceivers that are used within
hospital and ambulatory service. The main goal with
this device is that it will provide a more mobile
interface to existing ECG monitors in Hospital. The
device can be placed anywhere while the results shown
in conventional monitors. One of the advantages with
using this device is that it includes continuous
monitoring in a mobile environment and also that they
are designed to interface with existing medical devices.
This will somewhat reduce the reluctance of hospitals
to phase out old but expensive machines. These
devices can provide a more efficient and modern
standard interface to such expensive machines.
communicating over the air. Currently the wireless
technology used
8 Summary
Wireless networks for Medical Applications is
becoming a hot topic in the industry. With its potential
uses in the medical and home healthcare fields,
wireless networks have an important contribution in
improving lives of patients. Besides bringing comfort
to patients, there are large commercial benefits in the
area of reducing costs and improving equipment and
patient management.
In this survey paper, we discussed the benefits
of using wireless networks for medical applications.
We talked about how these new technologies can be
used to potentially reduce costs for hospitals,
government and insurance companies. With wireless
networks-based medical technologies, applications can
be designed to be less intrusive in patients' daily lives.
All applications based on scientific methods have a
development lifecycle. This is normally starting out
with a research project and moving onto
commercialization. Lessons learned here are applied
when designing newer applications in the future. We
talked about current and past research projects. We
also brought in some commercial applications that are
currently available in the market. Some of these
products are very innovative and have chances of
succeeding. With all new technologies, there are
chances of failures and success. Some of the projects
that we talked (i.e CodeBlue) about are long term
project and parts of them have already made the
transition to commercialization. Homecare is an area
where wireless networks for Medical Applications
have the most potential. Smart home [12] based
technologies are being designed which will eventually
care for our elderly and patient who need long term
care.
7.3.2 Airborne(TM) Embedded Wireless Device
Server Modules and Radios
Airborne(TM)[11] modules are an answer to
integrating old machinery with latest wireless
technology. Instead of phasing old but still useful and
functioning medical devices, these interface modules
will allow hospitals and clinics to make them useful
and last much longer. One of the main drawbacks of
using the heavy and expensive machines in hospitals is
that once placed in a room, they belong to the room
and the room belongs to them. These interface modules
will allow hospitals to reduce wiring and
incompatibility issues because machines will start
[
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[8] Victor Shnayder, Bor-rong Chen, Konrad Lorincz,
9. References
[1] D. Malan, T. Fulford-Jones, M. Welsh, and S. Moulton,
"Codeblue: An ad hoc sensor network infrastructure for
emergency medical care." In Proceeding of the International
Workshop on Wearable and Implantable Body Sensor
Thaddeus R. F. Fulford-Jones, and Matt Welsh. "Sensor
Networks for Medical Care", Harvard University Technical
Report TR-08-05, April 2005
http://www.eecs.harvard.edu/~brchen/papers/codebluetechrept05.pdf
Networks, 2004.
http://www.eecs.harvard.edu/~mdw/papers/codebluebsn04.pdf
[9] Project Connect
www.neilsquire.ca/section.asp?catid=123&subid=137&pagei
[2] Nicolas Chevrollier, Nada Golmie, "On the Use of
Wireless
Network
Technologies
in
d=353
Healthcare
Environments", July 2005, White Paper - U.S Department of
Commerce
[10] GMP Wireless Medicine, Inc.
http://www.wirelessecg.com/.
http://w3.antd.nist.gov/pubs/aswn05.pdf
[11] Airborne(TM) Embedded Wireless Device Server
[3] IMS Architecture & Specification
Modules and Radios
http://www.rennes.enst-
www.quatech.com/pdf/g_ab_wireless_device_server_module
bretagne.fr/~gbertran/files/IMS_an_overview.pdf
.pdf
[4] J. A. Stankovic, Q. Cao, T. Doan, L. Fang, Z. He, R.
Kiran, S. Lin, S. Son, R. Stoleru, A. Wood, "Wireless Sensor
Networks
for
In-Home
Healthcare:
Potential
[12] Smart Home Automation
www.smarthome.com/x10pclist.html
and
Challenges", in High Confidence Medical Device Software
and Systems (HCMDSS) Workshop, June 2-3 Philadelphia,
PA, 2005.
http://www.cs.virginia.edu/~control/medical/pubs/HCMDSS
05.pdf
[5] A&D Medical / Lifesource
http://www.lifesourceonline.com/and_med.nsf/index
[6] Nonin Medical, Inc. http://www.nonin.com/
[7] HealthFrontier, Inc.
http://www.healthfrontier.com/Products/
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