Passive RFID Asset Monitoring System in Hospital Environments Haleh Hakim1, 1
Hartford Hospital, CT
[email protected]
Raymond Renouf2,
2
Hartford Hospital, CT
[email protected]
3
University of Connecticut, CT
[email protected]
of the hospital. In the present work, a new RFID solution that uses passive RFID tags is proposed. The advantage of passive tags over active and semi-active tags is their lower cost and smaller size. Furthermore, passive tags do not need batteries and do not require maintenance. This prototype study is designed in order to prevent losing Telemetry Transmitters (TT) in the hospital. In addition, it will test the capabilities of the solution in order to introduce the technique to a much wider range of tracking and locating assets and people in the future. More details and advantages of this method are discussed in the following section.
Abstract— Passive Radio-Frequency Identification (RFID) technique is implemented in Hartford Hospital, Connecticut, for asset tracking. In particular, the technique is employed to monitor Telemetry Transmitters (TT) in order to prevent losing them. The work exploits the capabilities of passive RFID technology to determine the location of TTs as they pass through certain key spots in the hospital. The asset monitoring system is able to communicate with the hospital equipment management database, in order to get queries or send other necessary commands. An alarm feature is designed to alert the responsible staff members when one of the TTs passes through the common identifiable spots. Based on the proposed asset monitoring prototype, a Return on Investment (ROI) analysis and evaluation is conducted to justify the feasibility of installing a hospital-wide asset monitoring system with passive RFID solution.
II. PROBLEM STATEMENT One of the biggest concerns of hospitals is losing equipments, an example of which is TTs. The patient’s electrocardiogram (ECG) data are captured with TTs. The TTs are about the same size of a pocket personal computer and are attached to the patients in telemetry units during their stay in the hospital. They send the patient’s ECG data to a receiver system for processing. Data is then transmitted via a dedicate Ethernet interface to the Clinical Information Center (CIC) for viewing. TTs are highly mobile equipments that are often misplaced and lost due to the nature of their use. In this study, TTs were treated as high loss items that needed to be incorporated into an asset tracking system to be able to determine the location of TTs as they pass through certain tracks that they are usually lost in the hospital. The need for a tag attached to each TT containing information such as control number and original location, with the ability to communicate this information to a reader was identified.
I. BACKGROUND Radio Frequency Identification (RFID) is a method of automatic recognition and data capture, used to identify and track objects or people. It has the potential of tracking, locating enormous number of objects/people along with inventory and security functions. RFID has many applications in traffic control, retail stores, pharmaceutical industry, and clinical environments. RFID systems can be categorized according to active, semi-active, or passive tags they use [1]. Passive RFID tags are employed in this project as a prototype study of an asset tracking system in Hartford Hospital, CT, with a 900-bed major tertiary care and community health care center. Asset tracking of medical equipments in such a big facility is a major concern of the management. Currently, bar coding is the only system being used to track assets in the facility. The main drawbacks of bar codes are that they do not identify unique items, and handheld scanners function only in close proximity. More advanced and easier method of locating, tracking, and reading equipment, patients, and medication is possible with RFID tags. The Biomedical Engineering Department of Hartford hospital has been actively evaluating different pilot and prototype in the recent past. Reenajit Kaur [2] has conducted an active real-time RFID pilot study on a selected asset, i.e., infusion pumps, focusing on advantages of this real-time system in locating the pumps for maintenance technicians. However, a comprehensive real-time RFID system is not justified for all medical equipments and the whole real-estate
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John Enderle3
III. MATERIALS AND METHODS A. RFID Solution Architecture Passive RFID tags are not battery assisted. They receive their energy from the reader. The reader induces energy in the tag’s antenna, and the tag uses this energy to power its internal circuits to transmit data back to the reader. Readers were placed in appropriate locations to detect RF signal from the tags. A collector and an Ethernet concentrator are then used to collect data from the readers and convert them to packets to be sent to a server through the local area network (LAN).
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B. Software The software structure in this work consists of several modules, including Graphical User Interface (GUI), hardware interface, logic layer, and database interface, as depicted in Fig. 1. The logic layer embeds the required business logic including all the custom rules necessary to control and monitor the TTs. This information is logged in a database for further reference. In addition, the data will be processed by the logic layer rules to fire the necessary actions such as audible alarms, email alerts or pager notifications. A user-friendly graphical interface is also designed under Microsoft Visual Basic 6.0 which allows the operator to have thorough access to rules, logs and current system statistics in a dynamic manner [3]. Database interface layer is essentially an Active Data Object (ADO) which accepts the query from the user and retrieves the records from the hospital Database. It is also used for adding/editing and removing the records in the asset database containing equipment specification record along with the corresponding RFID tags. The hardware layer is responsible for receiving data from the RFID readers located in different zones. This layer is based on software development kits provided by the RFID company using certain APIs to configure the readers and read the RFID tags in the covered zones. Mail Server
Fig. 2 GUI Layout of Query Results B. Return on Investment (ROI) The hard ROI results show that in Hartford Hospital 18 cardiac Telemetry Transmitters were lost over the period of 18 months in years 2004-2005. Considering that each transmitter costs about $1,800, Hartford Hospital has an annual loss of $21,600. As summarized in the following table, a total ROI of $24,600 is estimated annually after the first year.
RFID Device
GUI
Hardware Interface
Database Interface
Logic Layer
Database Engin
TABLE I POTENTIAL RETURN ON INVESTMENT (ROI) Duration First Year Each Year After
Alarm Device
Annual TT Lost (1) $21,600 $21,600
RFID Solution (2) $5,800 $0,000
Time Savings (3) $3,000 $3,000
(ROI) = (1)+(3)-(2) $18,800 $24,600
Fig. 1 System Block Diagram
V. CONCLUSION
C. Financial Analysis Several cost benefits of the present RFID system was calculated and a return on investment (ROI) was estimated. The benefits include soft and hard categories. Hard ROI are savings or expenses for repurchasing the lost equipment. Soft ROI are savings in terms of the average time the staff spend in searching for the lost or misplaced equipments. Data for the hard ROI was calculated based on the increase in capital to acquire more equipment every year according to the amount of TT lost annually during the 2003-2005 time period. Soft ROI was calculated by shadowing technicians to quantitatively estimate the time spent looking for a TT.
In conclusion, passive RFID asset tracking system is a feasible technique to prevent equipment loss in hospital environments. The ROI shows a return in less than a year which further proves to be a beneficial investment for the hospital. REFERENCES [1] Health Devices 34(5). Radio Frequency Identification and its Potential in Healthcare. ECRI: May 2005. [2] K. Reenajit, Master’s Thesis. Design, Development and Evaluation of an asset tracking system, University of Connecticut, April 2005. [3] S. Mordzynski, Lowell Manuer, How to Use Visual Basic 6, 1st ed, SAMS: December 1998. [4] Brian, Implementing Wireless Communication in Hospital Environments with Bluetooth, 802.11b and other technologies, 1st ed. MDDI: New Jersey, 2003. [5] J. D. Enderle, S. Blanchard, Introduction to Biomedical Engineering, 3rd Ed., Academic Press: California, 2000.
IV. RESULTS A. Asset Tracking Hardware and Software The hardware is setup and tested on Bliss and High Building laundry rooms. The query results in the GUI view for easy identification is shown in Fig. 2.
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