Final Written Report.pdf

Final Report

SMART MATTRESS SYSTEM FOR PATIENT IDENTIFICATION

AND BEDSORE PREVENTION

ECE4007 Senior Design Project

Section L03, Koblasz

Smart Mattress Team

Bryan KuoPriyen PatelDev ShahXitij Shah

Tim Stamm

SubmittedDecember 11, 2008

Smart Mattress (ECE4007L03)

TABLE OF CONTENTS

Executive Summary.......................................................................................................... iii

1. Introduction....................................................................................................................11.1 Objective ...........................................................................................................11.2 Motivation .........................................................................................................11.3 Background .......................................................................................................2

2. Project Description and Goals .....................................................................................2

3. Technical Specification..................................................................................................3

4. Design Approach and Details4.1 Design Approach ...............................................................................................44.2 Codes and Standards........................................................................................114.3 Constraints, Alternatives, and Tradeoffs .........................................................11

5. Schedule, Tasks, and Milestones.................................................................................12

6. Project Demonstration..................................................................................................13

7. Marketing and Cost Analysis7.1 Marketing Analysis...........................................................................................137.2 Cost Analysis ...................................................................................................14

8. Summary........................................................................................................................16

9. References......................................................................................................................17

Appendix A........................................................................................................................19

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EXECUTIVE SUMMARY

Infections acquired in hospitals cost the healthcare industry billions of dollars each year

and result in numerous preventable deaths. These infections can result from patients developing

bedsores due to lying stationary for an extended period as well as lying on wet sheets. Another

issue is mistaking the patient in the bed for the wrong patient and giving incorrect medication or

treatment. To prevent these overlooked problems, the Smart Mattress verifies the correct patient

is occupying the bed, detects patient movement, and senses the presence of moisture.

Proper patient identification was accomplished by displaying the patient’s name, patient

ID, doctor’s name, and unique ID barcode on a PC monitor using RFID to read data from the

patient’s wrist or ankle tag. An array of pressure sensors was used to monitor patient movement

and warn staff when a patient needed to be moved. To detect moisture, a disposable mattress

using a conductive pattern between the top paper layer and the bottom biodegradable plastic

layer was placed on the bed. Since polymer, reinforced paper loses its strength when wet, air-

laid paper widely used in hospital applications safely provides a flexible, and low cost

alternative.

The demonstration for the Smart Mattress took place in a classroom of the Van Leer

building located on the Georgia Institute of Technology main campus. The functionality of the

mattress was tested by simulating several possible scenarios that could occur in a typical patient

room. Specifically, a test “patient” went through scenarios demonstrating the functionality of the

wetness detection system, the movement detection system, and the patient identification system.

When the system is mass-produced, the cost of each unit will be $1,765. With the system

being so cheap, a profit margin of 15 percent results in a final selling price of $2,030.

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1. INTRODUCTION

Nosocomial infections, which are infections acquired in hospitals are prevalent at a rate

of about 9.8 percent per every 1000 days that a patient spends in the hospital. These infections

cost the healthcare industry $4.5 billion and caused 88,000 deaths in 1995 [1]. These infections

can result from patients developing bedsores from lying stationary for an extended period or

wetting the bed. In other instances, the patient in the bed is mistaken for the wrong patient and

given incorrect medication or treatment. To prevent these overlooked problems, the Smart

Mattress verifies the correct patient is occupying the bed, detects patient movement, and senses

the presence of moisture.

1.1 Objective

The purpose of the project was to design an inexpensive mattress system that prevents

bed-related nosocomial infection and identifies occupants. The proposed features were that the

mattress should be able to detect occupant movement; the mattress cover should be able to detect

the presence of moisture. Pressure and moisture sensors connected to a system that will notify

hospital staff in the event of a problem. The mattress should also identify the patient and display

the patient’s name and barcode on a monitor for easy and secure medicine distribution. This

product’s target consumers were to be hospitals, clinics, and nursing homes.

1.2 Motivation

According to the CDC, 2 million people are infected with nosocomial infections every

year. Increasingly, patients are contracting MRSA infections, which are harder to treat with

antibiotics, as they are more resistant than normal bacterial infections [2]. Infection rates vary

between hospitals and nursing homes, but on average, 10 percent of hospital patients contract an

infection, while the average rate in nursing homes is 25 percent [3].

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Though other smart beds are available to hospitals, these beds have many extra features

not required by hospitals that already have equipment to perform these functions. The Smart

Mattress will operate using stand-alone devices to be cost-effective.

1.3 Background

Several different designs for smart beds are used to reduce the pressure on the patient [4].

The problem with the smart beds on the market is they are expensive and only prevent bedsores

by detecting patient inactivity, overlooking bed-wetting, which is also a major cause of bedsores.

In recent years, expansive research in the commercial uses of RFID has led to major

advances in the healthcare industry. The market for RFID tags and systems in healthcare is

expected to grow to $2.1 billion by 2016 [5]. In the hospital environment, it is important for the

doctor to be able to access a patient’s information as fast as possible in case of an emergency, or

to ensure the correct patient is given the correct medication.

2. PROJECT DESCRIPTION AND GOALS

The Smart Mattress was supposed to integrate seamlessly patient identification and bed sore

prevention into a typical hospital bed by doing the following:

Identify patients using RFID

Display patient information and barcode on a PC monitor

Detect moisture and pressure that could create bed sores

Alert staff if patient is in danger of developing bed sores

The Smart Mattress was to be equipped with a RFID receiver to communicate with wrist or ankle

tags worn by the patient. Once the patient was identified, an external PC monitor displayed the

name of the patient, patient ID, doctor’s name, and unique barcode that when scanned displays to

hospital staff the correct medications to administer. Pressure and wetness sensors also located in

the Smart Mattress detected the presence of fluid and monitor pressure changes. If the patient is

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in danger of developing bedsores, the hospital staff was alerted. The expected unit price of the

Smart Mattress is $2,030, which is cost-effective in the target market of hospitals and nursing

homes.

3. TECHNICAL SPECIFICATIONS

The following table shows the proposed and actual technical specifications for the

technology used to design the Smart Mattress. The previous passive RFID system did not meet

our range detection specifications. An active RFID system proved to be a better alternative as it

has a maximum antenna detection range of 35 ft. that is adjustable. A range of three feet was set

for the tags, as this range was sufficient for the purposes of detecting the patient lying on the bed.

The antenna for the RFID detection system was placed between a 2.5-inch thick high-

density memory foam and 1.5-inch thick low-density foam pad. The placement of the RFID

antenna in between the two-foam mattress pads and near the bottom of the bed provided the best

orientation for detecting a tag worn by the patient around the ankle. The antenna’s large and

adjustable maximum detection range of 35 ft secures that a three feet range is attainable. The

frequency of 433 MHz was chosen due to the commonality of equipment at this specification.

This high frequency is required so as to not interfere with other hospital equipment. Figure 1

shows the ranges that the RFID tags were detected based on the tag plane orientation; the degree

measurements were made from the vertical (positive Y) axis. Table 1 shows the specifications

that were proposed compared to the final specifications of the Smart Mattress.

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Figure 1. RFID tag orientation

Table 1. Technical Specifications

The inactivity monitoring system was implemented using four Force Sensing Resistor

(FSR) strips to measure the pressure applied by the patient to the mattress. The pressure strips

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were placed between the two foam mattresses on a cardboard base. The sensitivity range of the

pressure strips was calibrated by varying the voltage dividers connecting the strips to the Phidget

interface kit. Modifying the pressure range allows the pressure strips to measure up to 1,000 lbs.

4. DESIGN APPROACH AND DETAILS

4.1 Design Approach

The Smart Mattress project is comprised of patient identification and bedsore prevention

features. Patient identification will be accomplished using an RFID system, and bedsores will be

prevented by coupling movement and wetness monitoring systems. Each system will be

implemented separately using previous groups’ design solutions, and then modified in order to

combine them into a full product package.

Patient Identification

Proper patient identification will be assured by displaying the patient’s name, patient ID,

doctor’s name, and unique medication ID barcode on a PC monitor using RFID. The RFID

system will have four components: active RFID tags, antenna, a 433 MHz transceiver, and a

patient ID database.

Each tag has a unique ID corresponding to the tag’s owner. The RFID transceiver signals

the tag through an antenna. Upon receiving the transmitted signal from the antenna, the inner

circuitry in the tag returns the unique signal representing the binary ID assigned to each patient.

The response signal is detected by the antenna, decoded in the transceiver, and then processed on

a PC.

Once the transceiver detects a tag, the serial number of the tag is compared to a patient ID

database on the PC. In this database, information such as the patient’s name will be stored. A

bar code will be generated based off the patient’s unique ID. The patient’s name, patient ID,

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doctor’s name, and unique bar code will then be displayed on a PC monitor to help secure proper

medication delivery.

Bedsore Prevention

An array of pressure sensors are used to monitor patient movement and warn hospital

staff when a patient needs to be moved. Movements are monitored using the algorithm shown in

Figure 2. The movement monitoring system serves three main purposes. The system prevents

bedsores by detecting significant movements by the patient, or lack thereof. To accomplish this,

the system utilizes the four Trossen Robotics Force Sensing Resistors, which are located

equidistant from each other, to calculate the patient’s center of mass. The following is the center

of mass equation used.

(0*F1 + 1/3*F2 + 2/3*F3 + F4)/( F1 + F2 + F3 + F4) where FX is the force on strip X Eq. 1

In our system, a significant movement is defined as a 20 percent change, in either direction, from

the stored center of mass calculation. Finally, the patient monitoring system displays an alarm on

the monitor instructing staff to move the patient if the patient is inactive for more than 30

minutes.

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Figure 2. Movement detection algorithm.

The pressure sensing was carried out by several force sensing resistors (FSR) from

Trossen Robotics. The FSR functions by decreasing its resistance with an increase in force. The

sensitivity of the FSR was adjusted using a voltage divider, which was then interfaced with a PC

using the Trossen Robotics Interface Kit; all three of these components are shown in Figure 3.

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Figure 3. (a) TR Voltage Divider, (b) TR Phidget Interface Kit, (c) Force Sensing Resistor.

Figure 4 shows how the FSRs were laid out in relation to the patient and the mattress.

Figure 4. Pressure sensors on Smart Mattress.

The middle area of the bed is the best spot to put the pressure sensors because this is the area of

the body where bedsores are most likely to develop [6]. The FSRs will be placed in the bed so as

not to allow the sensors to bend.

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Wetness Detection System

A mattress cover consisting of two conductive loops was created in order to detect

wetness on the patient bed. The two conductive loops were made using conductive pieces of

tape. These two conductive loops, which are located near the middle region of the bed, were the

inputs into our wetness detection circuit. Combined with the patient inactivity monitoring

system, the wetness detection system greatly reduces the chances of developing bedsores. The

following sections describe how the conductive pattern and wetness detection circuit were

designed.

Conductive Pattern

The conductive pattern and the wetness detection circuit used on the prototype can be

seen in Figure 5 below. The two conductive loops are interfaced with the wetness detection

circuit using four leads at the edge of the mattress. Wetness is determined by monitoring the

output of the wetness detection circuit. Essentially, if the patient urinates on the bed (or wets the

bed in some other manner) the two conductive loops are shorted. Once the loops are shorted, the

output voltage of the wetness detection circuit is modified. The following section explains how

the wetness detection circuit was constructed and how wetness between the two conductive loops

affects its output.

Figure 5. Picture of conductive loops on prototype.

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Wetness Detection Circuit

The wetness detection circuit is shown in Figure 6 on the next page. As seen in the

figure, the wetness detection system consists of two 9V batteries, 6 resistors, and two

comparators. The conductive loops are in series with R2. Once the bed becomes wet, essentially

shorting the two conductive loops, R2 is bypassed. The shorting of R2 leads to a high output

voltage for the top comparator. This high output voltage is then processed by the Phidget 8/8/8

interface kit analog input sensor and the PC, and a “wetness alarm” is displayed for nurses to

view.

Phidget 8/8/8 Interface Kit

A Phidget 8/8/8 interface kit was used to interface the inactivity monitoring system and

the wetness detection system with the HP Slimline PC. Initially a PIC microcontroller was

proposed to integrate all aspects of our design together. Due to time constraints, implementing

the PIC microcontroller was not feasible, therefore the Phidget Interface Kit was utilized for the

Figure 6. Wetness and broken lead detection circuit.

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prototype.

Five of the eight analog inputs of the Phidget Interface Kit will be utilized to integrate the

wetness and inactivity detection systems. Four of these analog inputs will be dedicated to

monitor the 4 Trossen Robotics FSRs while one of them will be used to sample the wetness

detection circuit output.

4.2 Codes and Standards

The RFID technology implemented in the Smart Mattress system must meet the stringent

codes and standards of typical hospital equipment. RFID antennas pose a threat to patients if they

transmit a high-powered signal near patients. To minimize the power radiated by the RFID

antenna, the distance between the antenna and its receiver needed to be minimized. Several tests

were performed to determine the appropriate proximity of the antenna with respect to the

receiver in order to avoid harm to medical patients occupying the Smart Mattress.

Furthermore, the RFID system had to meet electromagnetic compatibility (EMC)

standards to prevent the interference with other significant medical equipment [8]. Specifically,

the RFID system must meet the standards specified by SC 31, which state that “device

manufacturers claiming conformance to this standard shall self-certify that RF emissions and

susceptibility comply with IEC 60601-1-2” [9]. The operating frequency of the RFID system

integrated in the Smart Mattress is 433 MHz; therefore, it meets the EMC requirements for

medical devices.

The active RFID system also had to meet transmitting range standards. In order to make

sure the RFID transceiver was not reading a patient tag in another room, testing was conducted

to verify that the transmitting range was not too large. Furthermore, testing was also done to

ensure that the transmitting range of the active RFID system would not read other patient tags in

rooms with multiple patient beds. According to tests, which are highlighted in Figure 1, the

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detection range was not greater than 4 ft. in either direction with respect to the transceiver. This

range would allow the transceiver to read tags on the bed, but not around the bed where other

patient beds might be located.

4.3 Constraints, Alternatives, and Tradeoffs

Alternatives to moisture detection systems exist, while complete wetness detection

systems requiring no assembly can be purchased. These systems often come with detailed

instructions and software to interface with a PC. However, a moisture detection system built by

the team will cost less because it can be created using cheap components that are easily

obtainable. This system can also be modified to interface with different hardware components.

Because cost and flexibility are important considerations in this project, the team-built moisture

detection system offers more advantages than a retail system.

Homemade RFID antennas present a different situation. Making an antenna is cheaper

than buying one. However, buying an antenna decreases the amount of time needed to design

and build the patient identification system because the antenna is ready to be used as soon as it

arrives. This project is a prototype, so keeping the project within time constraints is more

important than reducing costs.

5. SCHEDULE, TASKS, AND MILESTONES

The prototype of the Smart Mattress was built according to the timeline given below.

Table 2. Project Timeline

WBS

Task Name Duration

Start Finish Difficulty

Responsible Person

1 Define Project 21 days 8/18/2008

9/15/2008 Easy All Members

2 Acquire Parts 5 days 9/15/2008

9/19/2008 Easy All Members

3 Implement Microcontroller 11 days 9/22/2008

10/6/2008 Medium Tim

4 Implement Bed Sore Detection 29 days 9/22/2008

10/30/2008

High Bryan, Priyen, Xitij

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The team was divided into two subgroups that worked concurrently. Bryan, Priyen, and Xitij

focused on the bedsore prevention system. Dev and Tim concentrated on the patient

identification system. The subgroups met several times a week to work on tasks, and the

complete team met at least twice a week with the project adviser to discuss progress, problems,

and solutions. Both subgroups separated the tasks into subtasks to define responsibilities. These

are shown in the Gantt chart in Appendix A.

Construction of the Smart Mattress began on September 22. The hardware was installed

first. By October 13, both systems were ready to be tested and debugged independently. The full

system was assembled and was ready for demonstration by December 5th, 2008.

6. PROJECT DEMONSTRATION

The Smart Mattress was demonstrated in the senior design lab of the Van Leer building

located on the Georgia Institute of Technology campus. The team initially gave a power point

presentation explaining the background information, general functions and underlying

technology of the Smart Mattress. The functionality of the mattress was then tested by simulating

several possible scenarios that could occur in a typical patient room. Specifically, a test “patient”

went through scenarios that test the functionality of the wetness detection system, the movement

detection system, and the patient identification system. For example, to test the wetness detection

system, a team member poured water on the mattress. When the system detected the wetness, the

wetness alarm turned on to notify a nurse that the mattress was wet. The “patient” also simulated

cases that tested how these different systems (wetness detection, pressure detection, RFID, and

PC monitor) interact with each other.

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7. MARKETING AND COST ANALYSIS

7.1 Marketing Analysis

Many healthcare companies have developed “intelligent” patient beds in response to the

increasing occurrence of nosocomial infections. For example, TRADEWIN manufactures an

Alternating Pressure Mattress System that monitors pressure distribution and modifies airflow to

help prevent bedsores. The TRADEWIN 3000 8” Alternating Pressure Mattress system is sold

for $1,350 per unit [10]. MED-AIRE also manufactures a similar alternating pressure mattress

for $1,099 per unit [11]. Although the Smart Mattress system costs more than the previously

mentioned competitors, approximately $2,030 per unit, it possesses a unique set of features that

distinguish it from any intelligent hospital bed in the market.

The Smart Mattress system differs from many intelligent patient beds in the health care

industry because of its versatility. The proposed mattress system not only measure pressure, but

also measure wetness, which is a major contributing factor in the development of bed sores.

Along with bed sore prevention technology, the Smart Mattress also utilizes an RFID system to

display the patient’s name on a PC monitor located near the hospital bed. The monitor will also

display important medication information to prevent any potential medicine distribution errors.

7.2 Cost Analysis

Table 3 shows the cost of all the parts that will be used to make the Smart Mattress

system. The grand total of the parts to make one Smart Mattress system is $1,055. The most

expensive component is the RFID system, which includes the reader and the transmitter.

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Table 3. Part Costs

Part Quantity Unit Cost Total Cost

FSR Robotics Sensor Kit 4 $27 $108

Phidget 8/8/8 1 $80 $80

Wires/Cables 1 $15 $15

9V Battery 2 $7.50 $15

RFID Tag and Reader 1 $307 $307

Conductive Fabric Tape 100 ft $80 $80

Mattress Foam 1 $150 $150

Bed Sheet 1 $30 $30

HP Slimline PC 1 $250 $250

PC Monitor 1 $50 $50

Total Equipment Cost $1,055

Table 4 shows a list of the costs of developing the Smart Mattress system. Including the

labor to develop the system, the total cost of the initial Smart Mattress system is $34,350. The

labor cost was estimated based on the starting salary of $52,200 for someone who graduated

from the Georgia Institute of Technology with an electrical engineering degree [12]; this equals

$26.10/hour based on the 40-hour workweek. Fringe benefits and overhead were calculated at 25

percent each.

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Table 4. Development Costs

Component Labor

Hours

Labor

Cost

Total

Component

Cost

Pressure Sensor Testing 150 $3,915 $9,135Wetness Detection Testing 200 $5,220RFID Sensing 100 $2,610 $5,740RFID PC Monitor 120 $3,130Design Meetings 240 $6,265 $6,265

Total Labor 810 $21,140

Total Equipment Cost $1,055

Fringe Benefits, 25% Of Labor $5,285

Overhead, 25% Of Equipment,

Labor & Fringe

$6,870

Total Overhead $12,155

Total Project Cost $34,350

Table 5 shows the projected costs and revenue of when the Smart Mattress system is put

on the market. When the system is mass-produced, the cost of each unit will be $1,765. With the

system being so cheap, a profit margin of 15 percent was used for a final selling price of $2,030.

The projected rate of sales over five years is 15,000 units, for total revenue of $30,450,000 and a

total profit of $3,975,000.

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Table 5. Profit Projection

Equipment Cost $1,055

Assembly Labor $12

Testing Labor $8

Subtotal, Labor $20

Fringe Benefits, 25% of Labor $5

Subtotal, Labor & Fringe $1,080

Overhead, 25% of Material, Labor & Fringe $270

Subtotal, Input Costs $1,350

Sales & Marketing Expense, 20% of Production Price $270

Support & Warranty Expense, 10% of Production Price $135

Amortized Development Costs $10

Subtotal, All Costs $1,765.00

Profit, 15% $265.00

Selling Price $2,030.00

Total Revenue, Based on 15,000 Units over 5 years $30,450,000

Total Profit $3,975,000

8. SUMMARY

The prototype for the Smart Mattress was successful. The patient inactivity monitoring,

wetness detection and patient identification systems were successfully implemented and tested.

The inactivity monitoring system detected patients who had remained inactive for too long, and

the wetness detection system detected the presence of fluid. Both systems reported the current

status of the patient on the monitor. The RFID system identified the patient and displayed the

pertinent information on the monitor. The RFID tags were tested at different orientations and

ranges and exceeded our expectations. Figure 9 shows the final system with all of the

components.

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Figure 9. Final prototype of the Smart Mattress.

Future versions of this project should prioritize readying the product for manufacture by

decreasing costs, reducing power consumption, and ensuring patient safety and comfort.

Examples of ways to accomplish this are: replacing the Phidget 8/8/8 with a PIC18LF2321 (see

the following additional section for more details about using a PIC instead of the Phidget

Interface Kit), modifying the system to use an AC power supply instead of the two 9V batteries,

using RFID tags that fit comfortably on a patient's wrist or ankle, and implementing the system

on a printed circuit board. The product can also extend its applicability by using the RFID

system to identify hospital staff in the proximity of the patient's bed, detecting patient egress,

sending alerts directly to a nurse call station, and detecting fluids in other areas of the mattress to

account for IV leaks, sweat, blood, and vomit.

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PIC Microcontroller

A microcontroller-based design could reduce costs, lower current consumption, increase

patient safety, and provide a much more compact solution than a PC. Integrating patient

identification and bedsore prevention features into one compact product could be accomplished

using a PIC18LF2321 microcontroller as seen in Figure 7.

The microcontroller could be used in place of a PC to control and process data from the

RFID transceiver, FSRs, and wetness detection circuit. Using the onboard UART (universal

asynchronous receiver transmitter) communication between the PIC and RFID transceiver could

be accomplished via the RS232 standard. The FSRs could be monitored using the onboard ADC

and four of the PIC’s analog inputs. Wetness detection circuit outputs could also be tied to

analog input pins on the PIC.

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9. REFERENCES

[1] R.A. Weinstein. (July, 1998). Nosocomial Infection Update. Emerging Infection

Diseases [Online]. 4(3). [cited 2008 Sep 11], Available:

http://www.cdc.gov/ncidod/eid/vol4no3/weinstein.htm

[2] R. Moser, “Dirty Places, Part 12: Hospitals/Nursing Homes,” [Online Document],

[cited 2008 Sep 11], Available:

http://blogs.webmd.com/all-ears/2006/08/dirty-places-part-12-hospitalsnursing.html

[3] M. Haggerty, Gale Encyclopedia of Medicine, “Bed Sores” [Online], [cited 2008 Sep 11], Available:

http://www.healthatoz.com/healthatoz/Atoz/common/standard/transform.jsp?requestURI

=/healthatoz/Atoz/ency/bedsores.jsp.

[4] R&D Products, LLC, “The Smart Bed,” [Company Website], [cited 2008 Sep 12],

Available: http://thesmartbed.com/products.htm

[5] A. Lewcock, “Healthcare RFID market forecast at $1.2B,” [Online Document], 2007 July

09, [cited 2008 Aug 30], Available:

http://www.healthcareitnews.com/story.cms?id=7436

[6] P. Chung, Y. Hur, M. Wozniak, D. Yoon, "Disposable Mattress Cover with Wet Sheet

Sensors," [Online Document], [cited 2008 Sep 11], Available:

http://www.ece.gatech.edu/academic/courses/ece4007/08spring/ece4007l05/ak15/

proposal.pdf

[7] J.B. Peatman, Coin-Cell-Powered Embedded Design, Atlanta, GA: Quick&Low Books,

2008, pp. 7-14

[8] W. Khawaja, M. Saleheen, S. Sanyal, B. Virk, and R. Eiswerth, “Intellibed Hospital Bed

Add-On Kit For Improved Patient Safety,” [Online Document], [cited 2008 Sep 11],

Available:http://www.ece.gatech.edu/academic/courses/ece4007/08spring/ece4007l05/

ak11/files/Proposal.pdf

[9] C. K. Harmon, “RFID: Update on Standards and Regulatory Initiatives,”

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http://www.ece.gatech.edu/academic/courses/ece4007/08spring/ece4007l05/ak11/files/Proposal.pdf

http://www.ece.gatech.edu/academic/courses/ece4007/08spring/ece4007l05/ak11/files/Proposal.pdf

http://www.ece.gatech.edu/academic/courses/ece4007/08spring/ece4007l05/ak15/proposal.pdf

http://www.ece.gatech.edu/academic/courses/ece4007/08spring/ece4007l05/ak15/proposal.pdf

http://www.healthcareitnews.com/story.cms?id=7436


[Online Document], [cited 2008, Sep 12], Available:

http://www.aimglobal.org/members/news/templates/template.aspx?articleid=3302&zonei

d=45

[10] IDT Marketing, “Tradewind 3000 8” Alternating Pressure Mattress System,”

[Company Website], [cited 2008 Sep 12], Available:

http://www.alternatingpressuremattress.com/3000.html

[11] uCanHealth, “MED-AIRE 8” Alternating Pressure Mattress Overlay with Low Air Loss,”

[Company Website], [cited 2008 Sep 12], Available:

http://ucanhealth.com/goto.php?page=detail.php&graph1=14028&cat_page=alternating_

pressure_mattress

[12] Georgia Institute of Technology, “Bachelor’s Degree Candidates by Major,”

[Online Document], [cited 2008, Sep 12], Available:

http://career.gatech.edu/students/bachelor.pdf

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APPENDIX A

GANTT CHART

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