Writers Den

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CASE STUDY 9

ST. LUKE’S HEALTH CARE SYSTEM

Hospitals have been some of the earliest adopters of
wireless local area

networks (WLANs). The clinician user population is typically
mobile and

spread out across a number of buildings, with a need to
enter and access

data in real time. St. Luke’s Episcopal Health System in
Houston, Texas

(www.stlukestexas.com) is a good example of a hospital that
has made

effective use wireless technologies to streamline clinical
work processes.

Their wireless network is distributed throughout several
hospital buildings

and is used in many different applications. The majority of
the St. Luke’s

staff uses wireless devices to access data in real-time, 24
hours a day.

Examples include the following:

• Diagnosing patients and charting their progress: Doctors
and

nurses use wireless laptops and tablet PCs to track and
chart patient

care data.

• Prescriptions: Medications are dispensed from a cart that
is wheeled

from room to room. Clinician uses a wireless scanner to scan
the

patient’s ID bracelet. If a prescription order has been
changed or

cancelled, the clinician will know immediately because the
mobile device

displays current patient data.

http://www.stlukestexas.com/

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• Critical care units: These areas use the WLAN because
running hard

wires would mean moving ceiling panels. The dust and
microbes that

such work stirs up would pose a threat to patients.

• Case management: The case managers in the Utilization
Management

Department use the WLAN to document patient reviews,
insurance

calls/authorization information, and denial information. The
wireless

session enables real time access to information that ensures
the correct

level of care for a patient and/or timely discharge.

• Blood management: Blood management is a complex process
that

involves monitoring both patients and blood products during
all stages of

a treatment process. To ensure that blood products and
patients are

matched correctly, St. Luke’s uses a wireless bar code
scanning process

that involves scanning both patient and blood product bar
codes during

the infusion process. This enables clinicians to confirm
patient and blood

product identification before proceeding with treatment.

• Nutrition and diet: Dietary service representatives
collect patient

menus at each nursing unit and enter them as they go. This
allows more

menus to be submitted before the cutoff time, giving more
patients

more choice. The dietitian can also see current patient
information, such

as supplement or tube feeding data, and view what the
patient actually

received for a certain meal.

• Mobile x-ray and neurologic units: St. Luke’s has
implemented the

wireless network infrastructure necessary to enable doctors
and

clinicians to use mobile x-ray and neurologic scanning
units. This makes

it possible to take x-rays or to perform neurological
studies in patient

rooms. This minimizes the need to schedule patients for
neurology or

radiology lab visits. The mobile units also enable equipment
to be

brought to the bedside of patients that cannot be easily
moved. The

wireless neurology and x-ray units have also helped to
reduce the time

between diagnosis and the beginning patient care.

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Original WLAN St. Luke’s first WLAN was deployed in January
1998 and made the hospital

an early pioneer in wireless health care applications. St.
Luke’s first wireless

LAN was implemented in a single building using access points
(APs) made by

Proxim (www.proxim.com).

A principal goal of this initial installation was to improve
efficiency.

However, sometimes the WLAN had the opposite effect. The
main problem

was dropped connections. As a user moved about the building,
there was a

tendency for the WLAN to drop the connection rather than
performing the

desired handoff to another access point. As a result, a user
had to

reestablish the connection, log into the application again,
and reenter

whatever data might have been lost.

There were physical problems as well. The walls in part of
the building

were constructed around chicken wire, which interfered with
radio waves.

Some patients’ rooms were located in pockets with weak radio
signals. For

these rooms, a nurse or doctor would sometimes lose a
connection and have

to step out into the hallway to reconnect. Microwave ovens
in the

kitchenettes on each floor were also a source of
interference.

Finally, as more users were added to the system, the Proxim
APs, with a

capacity of 1.2 Mbps, became increasingly inadequate,
causing ongoing

performance issues.

Enhanced LAN To overcome the problems with their original
WLAN and reap the potential

benefits listed earlier in this case study, St. Luke’s made
two changes

[CONR03, NETM03]. First, the hospital phased out the Proxim
APs and

replaced them with Cisco Aironet (www.cisco.com) APs. The
Cisco APs, using

IEEE 802.11b, operated at 11 Mbps. Also, the Cisco APs used
direct

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sequence spread spectrum (DSSS), which is more reliable than
the

frequency-hopping technique used in the Proxim APs.

The second measure taken by St Luke’s was to acquire a
software

solution from NetMotion Wireless (netmotionwireless.com)
called Mobility.

The basic layout of the Mobility solution is shown in Figure
C9.1. Mobility

software is installed in each wireless client device
(typically a laptop,

handheld, or tablet PC) and in two NetMotion servers whose
task is to

maintain connections. The two servers provide a backup
capability in case

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one server fails. The Mobility software maintains the state
of an application

even if a wireless device moves out of range, experiences
interference, or

switches to standby mode. When a user comes back into range
or switches

into active mode, the user’s application resumes where it
left off.

In essence, Mobility works as follows: Upon connecting, each
Mobility

client is assigned a virtual IP address by the Mobility
server on the wired

network. The Mobility server manages network traffic on
behalf of the client,

intercepting packets destined for the client’s virtual
address and forwarding

them to the client’s current POP (point of presence)
address. While the POP

address may change when the device moves to a different
subnet, from one

coverage area to another, or even from one network to
another, the virtual

address remains constant while any connections are active.
Thus, the

Mobility server is a proxy device inserted between a client
device and an

application server.

Enhancing WLAN Security In 2007, St. Luke’s upgraded to
Mobility XE mobile VPN solution [NETM07].

This migration was undertaken to enhance security and
compliance with

HIPPA data transmission and privacy requirements. Mobility
XE server

software was deployed in the IT department’s data center and
client

software was installed on laptops, handheld devices, and
tablet PCs.

With Mobility XE running on both clients and servers, all
transmitted

data passed between them is encrypted using AES (Advanced
Encryption

Standard) 128-bit encryption. Mobility XE also serves as an
additional

firewall; devices that are not recognized by the Mobility XE
server are not

allowed to access the network. This arrangement helped St.
Luke’s achieve

its IT goal of having encryption for all wireless data
communications.

Mobility XE also enables the IT department to centrally
manage all

wireless devices used by clinicians. This allows them to
monitor the

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applications currently being used by any device or user, the
amount of data

being transmitted, and even the remaining battery life of
the wireless device.

If a Mobility XE device is stolen or lost, it can be
immediately quarantined by

network managers.

IT executives at St. Luke’s view wireless networking as key
lever in their

quest to increase clinician productivity and improved
patient care. Mobile

EKG units have been deployed bringing the total of wireless
devices in use to

nearly a 1,000.

Discussion Questions 1. Visit the NetMotion Web site
(www.netmotionwireless.com) and access

and read other Mobility XE success stories. Discuss the
patterns that can be observed in the benefits that Mobility XE users have
realized via its deployment and use.

2. Do some Internet research on the security implications of
HIPPA

requirements for hospital networks. Discuss the major types
of security mechanisms that must be in place to ensure hospital compliance with
HIPPA requirements.

3. Do some Internet research on the use of VLANs in
hospitals.

Summarize the benefits of using VLANs in hospitals and
identify examples of how St. Luke’s could further enhance its wireless network
by implementing VLANs.

Sources [CONR03] Conery-Murray, A. “Hospital Cures Wireless
LAN of Dropped Connections.” Network Magazine, January 2003. [NETM03] Netmotion
Wireless, Inc. “NetMotion Mobility: Curing the Wireless LAN at St. Luke’s
Episcopal Hospital. Case Study, 2003.
Netmotionwireless.com/resources/case_studies.aspx. [NETM07] Netmotion Wireless,
Inc. “St. Luke’s Episcopal Health System: A Case Study in Healthcare
Productivity.” 2007. Retrieved online at:
http://www.netmotionwireless.com/st-lukes-case-study.aspx

http://www.netmotionwireless.com/

http://www.netmotionwireless.com/st-lukes-case-study.aspx

CASE STUDY 9

Original WLAN

Enhanced LAN

Enhancing WLAN Security

Discussion Questions

Sources