Keeping track of portable medical devices throughout a hospital can be time-consuming, with cost and maintenance implications. But RFID technology may
provide a valuable alternative to traditional equipment libraries
Jason Britton, CSci MIPEM, Clinical Scientist, Medical Physics Department, Royal Alexandra Hospital, Paisley, Scotland,
Portable medical devices such as infusion pumps and non-invasive blood pressure monitors (see Figures 1 and 2) are
becoming an increasingly valuable resource in the delivery of healthcare. They will typically move between different areas of the hospital as clinical demands dictate. Periodically, usually about once a year, they will also be subject to a technical inspection by a medical device maintenance organisation.
The purchase costs of commonly used portable medical devices may be as much as £5,000 per unit, and there may be a ratio of two to three of these devices per inpatient bed.
It is not uncommon for portable medical devices to become unevenly distributed across the hospital. A high proportion of the devices available may accumulate in relatively few areas and, as a result, a number of them may be underutilised. In some cases, the devices may become “lost” within the equipment management system. This can mean the equipment is not subject to periodic maintenance inspections, thereby exposing patients to increased risks if these devices are subsequently used clinically.
Clinical and technical staff can also waste significant amounts of time looking for portable medical devices either to treat patients or to transfer to a laboratory for periodic maintenance checks. Initial estimates made by the medical physics department at the Royal Alexandra Hospital demonstrate the time lost looking for portable medical devices may amount to the equivalent of one technician’s working time over a period of a year. The time wasted by hospital staff undertaking this task in private hospitals may be far higher due to the high prevalence of single-patient rooms.
Portable medical devices are therefore significant hospital assets that require appropriate, efficient and cost-effective management solutions.
To improve the management of these devices, some hospitals have set up equipment libraries. These are strongly advocated by the National Patient Safety Agency and the Medicines and Healthcare products Regulatory Agency.[1,2] Equipment libraries pool large numbers of portable medical devices, and these are then loaned to different departments when required. Theoretically, once the borrower has finished with a device, it should be returned to the equipment library, where it is cleaned and checked in preparation for the next loan.
Equipment libraries typically require a separate room with an area between 20 m2 and 30 m2. In the private hospital sector, it may be difficult to justify the provision of a library due to space constraints or other service pressures. Issues relating to access and staffing of the equipment library also need to be addressed. Equipment libraries are not able to track the location of the loaned equipment if it is then moved to another clinical area.
An alternative solution to an equipment library is to track the location of portable medical equipment as it moves around the hospital, using radiofrequency identification devices (RFIDs).
Considerable development of RFID equipment tracking systems has been undertaken by the retail sector in providing real-time, efficient, supply chain solutions. RFID technology now appears to be sufficiently mature, that it can be successfully deployed in both private and National Health Service hospitals.
In generic terms, a portable medical device tracking system consists of identifiable separate components. Viewed from the medical device these are:
- A device identification tag: a tag is placed on the medical device that enables it to be tracked. This could be either a passive device whose identity code is “read” by the tracking system, or an active device that transmits its unique identity code, either at regular intervals (usually every 30 seconds) or when prompted by the tracking system. The tag will have a visible unique identification code that is associated with the portable medical device’s asset number and registered with the computer system and software.
- Signal detectors: a system of detectors or readers located at selected places within the hospital that will “read” the device identification tags when they come into range. In practice, more than one detector picks up the signals from the device identification tags and, by measuring the strength of the signals received, the system is able to make decisions as to the correct location of the tag.
- An electronic data communications network: to connect the various detectors or readers and transmit data to the computer system and software. Physically, in most cases, this can be integrated with the standard cable-based communications network installed in the hospital.
- Computer system and software: to record and collect location information from the device identification tags via the detection system and network. The spatial and temporal information of the device identification tags, attached to the portable medical devices, is presented in a format that can be easily understood and interrogated if required. This allows clinical and technical staff to readily find the location of portable medical devices.
In essence, an equipment tracking system based around RFID technology should be able to provide information on the location of all portable medical devices, 24 hours a day, seven days a week – thus overcoming one of the main limitations of a traditional equipment library. The RFID equipment-tracking system should be able to make up a virtual equipment library without the need to provide a physical location or find staff to run the service.
Overview of the solution at Royal Alexandra Hospital
The solution at the Royal Alexandra Hospital involves the use of active AeroScout device identification tags, which send radio-frequency signals (2.4 GHz) to the nearest set of detectors. The detectors used are ceiling-mounted wireless access points manufactured by CISCO systems.
The density of wireless access points is higher when compared with the use of wireless technology for data communication applications. This is necessary to achieve sufficient accuracy in locating the tags.
The wireless systems control software collates the data from the wireless access points via the network. This is then sent to a third-party software application (Resourceview supplied by Airetrak), which displays the information in a form that can be easily understood by both clinical and technical staff.
Any member of the health board can theoretically access the Resourceview application software using a standard networked desktop computer running Internet Explorer 6. Users are able to search for the location of specific types of equipment and view the history of a portable medical device as it is moved throughout the hospital. The software also allows the systems administrator to associate different tags to portable medical devices and define zones on specific floors. The Resourceview software has the advantage that it can be used with RFID infrastructures installed in more than one hospital.
A screen shot from the system running at the Royal Alexandra Hospital is shown in Figure 3.
Experiments have been undertaken to see whether the signals from device identification tags or wireless access points can interfere with the function of portable medical devices, in particular, volumetric and syringe infusion pumps.
The power levels of the signals from both the tags and the wireless access points are one-tenth that emitted by mobile phones. In all experiments conducted to date, the portable devices fitted with an identification tag have worked within the manufacturer’s published specifications. A search of the published literature in this area also demonstrates that RFID technology operating at 2.4 GHz has not been raised as an issue.
Potential health effects
The Health Protection Agency (HPA) in the UK has issued a clear statement on the potential health effects of wireless networking technology. This can be found on the website using the link provided. Two of the key findings from the HPA article are described below:
There is no consistent evidence to date that wireless networking technology adversely affects the health of the general population. The signals are very low power, from both clients and the access points, and the results so far show exposures are well within internationally accepted guidelines.
Conclusions and areas for future developments
As the equipment tracking system is rolled out across the Royal Alexandra Hospital, it is hoped that it will save both nursing and technical staff significant time in looking for portable medical devices. The system will form a virtual equipment library, as there is currently no static facility within the hospital and there are no plans to develop one in the future.
The implementation of a wireless local area network (LAN), based on well-established communication standards with a high density of access points, should also provide a number of additional benefits. Some of these are:
- The wireless LAN can be used to improve communications between clinicians working in the hospital through the use of wireless network phones, commonly referred to as “Wi-Fi phones”. These devices are similar to conventional mobile phones but will only communicate with the wireless LAN and, as such, operate at relatively low power levels. It is also possible to integrate the function of Wi-Fi phones with existing hospital phone networks. The potential use of this technology is actively being investigated as a means of improving communications with inpatient hospital services.
- The wireless LAN can be used to transmit data to mobile clients such as laptop computers. The speeds at which data can be communicated over wireless access networks are continuously being improved. A new standard is due to be launched in June 2009, which will support communication rates approximately six times higher than the maximum currently being achieved.
- Specific types of tags can also be purchased incorporating telemetry apparatus. For example, tags including emperature sensors can be placed in refrigerators used to store drugs and continuously monitor the internal temperature. If the temperature goes above 5˚C, then the system can be configured to generate an alert, which can be communicated to an operator.
In summary, any hospital without an equipment library may find the implementation of RFID technology attractive as a means of improving the management of portable medical devices. However, this should be undertaken as part of an
overall strategy to introduce wireless LAN infrastructure
together with Wi-Fi phones and mobile data communication. This is seen as necessary to ensure that full return on the investment is achieved.