1. ZIGBEE TECHONOLOGY
Location, Identification and Tracking at Hospitals
Authors: Serafin Arroyo, Jose Manuel Blasco
TSB
Soluciones Tecnológicas para la Salud y el Bienestar S.A.
Ronda Auguste y Louis Lumiere 23, Nave 13
Parque Tecnológico de Valencia
46980 · Paterna, Valencia · Spain
Tel: +34 96 182 71 77
Fax: +34 96 182 94 15
serafin.arroyo@tsbtecnologias.es
www.tsbtecnologias.es
April 27th, 2010
Keywords: E-Health, Management of patients, optimization of resources, clinical security, avoid errors,
identification.
Abstract: This paper summarizes the situation in hospitals regarding identification, security, location
and tracking of patients, providing a solution based on ZigBee technology. The major benefits that medical
and administrative users have identified are the easy handling of the system, the benefit to get real time
statistics and information of patient behavior, the automatic security to identify patients at certain areas, the
possibility to control time processes. Also the availability of all the information received to optimize the
resources and to planning agendas of the clinical staff is a key advantage.
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2. Contents
1. INTRODUCTION ...................................................................................................................... 3
2. WHAT IS REQUIRED AT HEALTH ENVIRONMENTs? ...................................................... 3
3. INDOOR LOCATION TECHNOLOGIES: AN OVERVIEW .................................................. 4
THE TECHNOLOLGY CHOSEN: ZIGBEE ........................................................................................ 5
4 HOW IT WORKS? ......................................................................................................................... 6
4.1 The system .............................................................................................................................. 6
4.2 Communications and location capability ................................................................................ 7
5 FUNCTIONALITIES...................................................................................................................... 8
6 CONCLUSIONS ............................................................................................................................. 9
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3. Location, Identification and Tracking at Hospitals
1. INTRODUCTION
Today the clinical security in hospitals and clinics is a key issue in the health system. As you know,
location and identification systems are well deployed and used for outdoor environments. Technologies
such as GPS (Global Positioning System) or LBS (Location Based Service) are already consolidated in
our day to day life.
But in case of indoor scenarios, there is still a huge discussion going on and it is not clear which system
could be more appropriate to cover the necessities of each case. In particular, when we talk about hospital
and clinical scenarios, this issue becomes critical.
The possibility of always knowing where your patients are located provides the tremendous opportunity
to the hospital to improve patient’s safety and clinical effectiveness. From the moment of admission the
patient could be always visible to the care team, which would be a big advantage in favor of the patient’s
security and his care processes.
With a simple query to a centralized system, an authorized:
• physician can find a patient during rounds
• nurse can find a patient for time-sensitive therapies or medication
• specialists can see that a patient is on the way for a procedure
When both patients and clinical teams are covered by a real time location system, the technology enables
an objective measure of patient and provider interactions.
This paper presents a ZigBee solution approach, an effective system to fulfill the requirements of a real
time location system in hospital scenarios.
2. WHAT IS REQUIRED AT HEALTH ENVIRONMENTS?
For health care environments a location, identification and tracking system needs to cover and guarantee a
list of features to work successfully and cover its special requirements:
Precision
Precision in hospital and clinic environments is defined as room level approach or even as area level
approach. People and devices can be located in these areas with this level of location precision, where
areas are predefined by the hospital according to its convenience.
For example, triage is an essential function in Emergency Departments (EDs), where many patients may
be present simultaneously. Urgency refers to the need for time-critical intervention. Patients triaged to
lower acuity categories may be safe to wait longer for assessment and treatment but may still require
hospital admission. Knowing that a patient is in triage, not just in the ED, that a device is clean and
available in the supply closet, not just in the unit and other information will improve the processes in
general, providing a more effective spent of resources.
Real time access to information
A centralized system needs to be available for medical and administrative staff on real time. Area and
room level definition accuracy need to be adapted to the medical processes needs for each case, to
provide the tools to improve efficiency and effectiveness of the hospital unit.
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4. Location, Identification and Tracking at Hospitals
The system can locate medical equipment, staff or patients at real time justifying its costs for the
hospitals.
Secure identification
A security system that reads automatically, for example, when the patient enters a room, will improve and
secure the identification of a patient. Also the possibility to know at firsthand the identity and any other
important background information about the patient wearing the location device is an improvement on a
secure patient care process.
Tracking and analytics
Through a central system, devices and people are monitored so that their position, movements and actions
are reported in real-time. It provides information about the movements of a patient from one area to other,
the time spent at each one and the tracking of patient activities daily. The system offers the possibility to
record the patient’s habitual movements, to produce statistics such as length of time spent in one area,
length of time needed to move from one area to another, etc., as well as the percentage usage of areas and
rooms, load and flow or patients, etc.
At the same time, hospitals can define alerts based on any combination of patients, staff and equipment
that come together in a specified location for a defined period of time. These “alerts” generate
notifications that can be sent via several ways to the interested parties.
Usability and environment
Other requirements to be taken in account for this kind of installations are:
• No electromagnetic interference with devices or other networks.
• Wearing comfort of the tags for the patients.
• Long battery life up to more than one year.
• Easy to clean.
• Tamper resistant.
• Easy installation and maintenance.
• Scalability of the system in case of new areas or more precision is required.
3. INDOOR LOCATION TECHNOLOGIES: AN OVERVIEW
Looking on indoor systems to provide real time location functionalities, ZigBee appears as the most
appropriate solution for health environments. Short analysis of other possible technologies is provided, to
highlight the benefits and advantage of a ZigBee based solution.
RFID passive
These systems are extensive used, but there are some limitations that provide serious doubts about its
convenience to the health environments:
• The system allows reading of patient information just in case that the distance to reader is less
than one meter. If the tag is out of this radio, there is no information about the position or identification of
the patient.
• Traceability functions are very limited, and cannot provide real time information. Only when the
patient passes by a control point, the system can really provide the position of the patient.
• Costs: RFID tag cost is low, but infrastructure associated is expensive and need substantial
installations in the building. Also, the use of this kind of RF passive tags is created for just one use, being
cheaper in a short term system but increasing the cost along the run of the hospital.
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5. Location, Identification and Tracking at Hospitals
Wi-Fi
Wi-Fi system has been developed to enable devices such as a personal computer, video game console,
mobile phone, MP3 player or personal digital assistant to connect to the Internet. These systems have
been also offered with the possibility to provide location capabilities. Main argument has been the reuse
of the same network as provided for internet and data networking. However, as the main target for Wi-Fi
systems is connectivity, for health environment location requirements presents significant doubts:
• The size and weight of a Wi-Fi tag to be used by patient is much bigger and heavier, being
therefore not very comfortable.
• All of these devices need much energy consumption, making really the recharge process and the
battery replacement an issue to be considered. It seems that system could be very valid to locate
equipments or devices that already have batteries and are normally recharged regularly. But for
patients at hospitals, it seems an important barrier that has to be taken in consideration.
• Even this approach has the advantage to reuse the Wi-Fi point of connection, for location
purposes, the number of these Wi-Fi routers increase significantly, which does not help saving
costs.
Bluetooth
Bluetooth seems to be a real option for location systems. The system can be specially useful, since many
mobile devices (mobile phones, PDAs, notebooks, ...) includes Bluetooth capabilities. For example, it can
be very useful for contextual information systems. When a user demands information from its mobile
device, the response will be configured depending on the origin of this request. This example can be
defined in a museum, exhibition or trade show, in which the user can ask questions such as where is the
exit or the toilets. Another application would be a system that locates a device in a transparent way. That
is, a mobile device will be located without user request. Suppose the case of a fair, in which each visitor
receives a terminal susceptible to be located; in this way the organization could take a control of the visits
’stands’, adapt the quality of the contents for future editions.
But in case of health environments, with the precision requirements, battery consumption and cost,
location based systems on Bluetooth seems to be out of the scope.
ZIGBEE
Taking in account the systems described above, ZigBee is identified as the right solution for health care
scenarios that:
• Allows to have a cost/effective solution which fulfills the room level accuracy requirement
• Minimizes the size and weight of tags to be used by the patient
• Provides long battery life, avoiding recharges and replacement processes in the day to day work.
• Creates a scalable network where not only location, identification and tracking is provided, but
also can be reused for near future sensor development in the health sector and ambient
intelligence.
THE TECHNOLOLGY CHOSEN: ZIGBEE
A ZigBee based real time location system will help health environments to resolve important problems
through the effective identification, traceability and location of people and objects.
ZigBee technology is easy to be integrated in other systems and is scalable, thus ensuring its compatibility
with potential new versions, other systems as well as future needs.
Along with the ZigBee network with location system beacons, and an advanced location algorithm, it is
allowed for the hospital to scan people across all areas, thus ensuring the optimum performance of the
system.
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6. Location, Identification and Tracking at Hospitals
The system is flexible, adaptable and can be configured individually for each case, which means that each
hospital defines a solution that is custom-built to meets its needs.
As technical characteristics, the ZigBee real time location system:
• works on ISM bandwidth (Industrial, Scientific and Medical) (2.4 GHz)
• follows ZigBee Standard 2007 and Pro including location attributes
• provides coexistence with WiFi, Bluetooth and other wireless communication systems
• includes a central control application to provide location, identification and tracking
• is easy to be integrated in other systems
• is scalable and compatible with new versions
• provides a mesh network platform
• is scalable to attend more precision and accuracy requirements, being Plug-and-Play to
existing infrastructure
• uses miniscule bandwidth
Figure 1: Primary beacons – router/gateway and wristbands – end device
4 HOW IT WORKS?
4.1 The system
The system takes an RF platform as its base and it is made up of the following parts:
• Infrastructure of fixed Beacons that enable zones to be mapped out in order to locate patients and
assets:
o Primary beacons also including Ethernet connection and acting as gateway
o Secondary beacons acting as routers
• Patient wristbands as end device that enable identification and location of patient, as well as
providing access to patient´s personal information.
• SDIO ZigBee card included in PDAs or notebooks to provide ZigBee capabilities to these
devices that allows patient identification as well as access to patient’s information anywhere and
anytime by the doctors.
• All information is stored on one central server, which has in-built tools to provide location,
tracking and identification functions.
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7. Location, Identification and Tracking at Hospitals
4.2 Communications and location capability
• Communications:
The location system as a whole is a ZigBee mesh network containing all kind of device types. The central
ole
server acts as the ZigBee network coordinator. Both primary and secondary beacons are routers among
the network, and the wristbands and mobile identification devices are end
end-devices.
One of the key points that make this system special compared to a normal ZigBee network is that the
coordinator does not need a RF interface. Very often Hospitals are enormous buildings where the
infrastructures are not sufficiently close ones to the others to take profit of meshing in order to reach any
t
node in the building. So, a gateway based solution is proposed for this kind of installations, where special
gateway-based
routers (primary beacons) use both RF and Ethernet to transmit ZigBee frames, in such a way that the
ZigBee stack in this kind of nodes just differ in the PHY layer. This solution allows the coordinator in this
system to be placed in a remote server’s area, or even, in a different building than the rest of the network.
Figure 2: Network structure
At the present, the whole system works using ZigBee 2007, but it is moving to ZigBee PRO. The main
reasons for this upgrading are th need for mobility in both wristbands and mobile devices, the higher
the
security level which matches with security and privacy requirements among hospital environments, and
privacy
the network scalability offered by the use of stochastic address assignment.
Obviously, the use of ZigBee allows other ZigBee devices to associate to the network. Since Continua
Health Alliance defined ZigBee as the technology used for certified LAN devices, it makes sense to
include some medical devices in the hospital by using this proposed infrastructure.
• Location over ZigBee
The location engine runs in the central server acting as the ZigBee coordinator. While in other approaches
nator.
on ZigBee based location the device calculates its own position by itself, so that when another device
needs to know this information has to communicate with it, in the proposed system, location is calculated
in the server, and any device in the network, even if it has not special location capabilities, can be
positioned among the infrastructure.
This location structure does not fit a fully ZigBee profile specifically. The aim is to promote the
ot .
standardization of this method over any ZigBee network and any profile. At the present, the system is
d
designed to perform ZigBee Health Care Profile approach, since it is meant to be installed at hospitals
, hospitals,
but the system can be adopted to support other scenarios
scenarios.
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8. Location, Identification and Tracking at Hospitals
5 FUNCTIONALITIES
• Basic Clinical Security (Identification):
This system's basic security measures are based on identification, in order that detailed and always
reliable information about the patient is provided in different situations. The solution offers two options:
o Identification upon request of health care personnel, using PDA or notebook as scanner
(similar to passive RF readers or barcode scanners) to identify patient details.
o Automatic identification upon entry in a covered area, whereby an automatic identification
check is made on each person (primarily patients) entering the area.
Figure 3: Identification functionality
• Location capability
It enables the location of patients and offers the adjustment of different degrees of precision, for example
the movement from a specific room to a general area. Thus it enables to locate a patient or employee in
real-time inside the hospital
• Physical Security
o of assets via alerts when an asset is not in the right place or time.
o of patients with alerts when patients are not in the right area at the right time.
• Traceability
o Tracking of the patent’s movements and assets, which are recorded and shown in
statistics such as length of time spent in one place, length of time needed for going from
one room to another etc., as well as the usage of areas and rooms, load and flow or
patients, etc.
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9. Location, Identification and Tracking at Hospitals
Figure 4: Tracking and location of patients functionality
• Monitoring of vital signs
Wristbands or more advanced ZigBee devices enable continuous monitoring of vital signs while on the
move of patients their transmission of measurements can be done via the same infrastructure used for
location. This concept is already accepted by Continua Health Alliance, having been selected ZigBee
standard as Continua´s new low power local area network (LAN).
6 CONCLUSIONS
ZigBee seems to be a real appropriate solution for location, identification, security and traceability of
patients in different health scenarios. This solution equips a hospital with identification, localization,
information, clinical and physical security and monitoring support applications, that help to manage the
procedures and resources (both patients and assets) inside health facilities, providing tools that help to
manage effectively and efficiently the day to day work.
The major benefits that medical and administrative users have identified are:
• Easy handling of the system for patients and processes at hospital.
• Benefit to have real time statistics and analysis of patient behavior, also under request.
• Automatic security provided by the system to identify patients.
• Possibility to control time processes and to optimize the resources and the planning of agendas
of the clinical staff.
• Flexibility to define areas to be covered and ability to adapt the network according to new needs.
Furthermore the system is planned to be able to integrate and reuse the ZigBee network created by the
location system for other purposes. Other applications and functions, integrating sensors and other
monitoring devices, can be connected and integrated.
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