The Internet lies at the heart of today’s social, educational and business worlds. The next logical development for such communication pathways is to use this global network over a variety of portable wireless devices for additional biomedical and laboratory applications
Interestingly, more than 500,000 wireless, or “Wi-Fi,” local area networks were implemented in the U.S. health care market during 2010, representing a 50% increase from the year before. Globally, Wi-Fi technology in health care increased by 60% – according to a report last year by ABI Research, a US technology market research company.
The USA is the greatest adopter compared to other regions analysed by ABI. By 2015, they expect Wi-Fi technology in the US health market to nearly double the 2010 figure to more than 1 million new Wi-Fi LAN access points. So how might this US WiFi revolution affect the European market?
“Wi-Fi” describes a local network that sends and receives information electronically using only radio waves – no wires. Technically, only a wireless network using “WiFi Alliance Certified” components is a true Wi-Fi network. However, “WiFi” has been generalised to mean any wireless network that complies with the IEEE 802.11 protocols whether the components are officially certified or simply marketed as compatible.
IEEE 802.11 is a set of standards for implementing wireless local area network (WLAN) computer communication between the 2.4 and 5 GHz frequency bands. The 802.11 family consists of a series of amended versions denoted by a suffix letter, since the original standard was introduced in 1997. It wasn’t until 1999 when 802.11b became the first widely accepted version, followed by 802.11g in 2003, with 802.11n, remaining as the current standard since 2009.
The 802.11b and g use the 2.4 GHz band reserved for industrial, scientific and medical radio applications each incorporating specific signaling algorithms to reduce the possibility of interference from other devices operating in the same frequency, such as microwaves. 802.11n uses more sophisticated techniques at either 2.4 or 5GHz allowing the potential for faster data speeds and less interference.
The 802.11 standard divides each of these versions (b, g and n) into channels, in the same way radio and TV broadcast bands are sub-divided. Channel use is regulated by country, Japan permits the use of all 14 channels while most European countries block channel 14; North America and some South American countries allow channels 1-11 only.
From a healthcare equipment manufacturer’s point of view, employing wireless communication 802.11b/g/n capability virtually assures full international WiFi compatibility, even though the Americas are limited to 11 channels.
The desire to communicate increased data at faster speeds conflicts with the mobility of the broadcasting device. Graph 1 summarises the relationship between data speeds and mobility.
Mobile phones using the GSM network are more suited to mobility but provide slower data speeds while faster data speeds can be achieved with WiFi enabled devices being less suited to mobility.
The limited practical range of Wi-Fi confines mobile use to such applications operating within range of an access point or “hotspot”.
Table 1 shows that the standards can be matched to applications depending on transmission range and data transfer speeds required. Enhancements in battery life technology (Lithium) have facilitated the opportunities for portability since WiFi broadcasting is power hungry.
Understandably, since wireless networks were introduced, security has been a concern to users.
In 2001, weaknesses in the initial data security mechanism – the Wired Equivalent Privacy (WEP) –were revealed. In 2003 Wi-Fi Protected Access (WPA) replaced WEP giving greater security. In 2004, WPA2 replaced WPA implementing a new advanced encryption mode (AES) with strengthened security. Since 2006, WPA2 certification is mandatory for all new devices to bear the Wi-Fi trademark.
Wi-Fi now operates in over 200,000 public hotspots and in tens of millions of homes, businesses, university campuses, hotels and hospitals worldwide. The current version of encryption (WPA2-PSK/AES) is considered extremely secure, provided users employ a strong password.
A small percentage of WiFi users have reported adverse health issues after repeated exposure and use of WiFi, though there has been no publication of any effects being observed in double-blind studies. The World Health Organisation and the UK Health Protection Agency report there are no known long term effects of Electromagnetic Hypersensitivity, noting that exposure to Wi-Fi for a year results in “same amount of radiation from a 20-minute mobile phone call.”
|Graph 1: Data speed versus mobility|
Wi-Fi networks are being used to enhance communication inside hospitals, where cellular networks are sometimes less reliable or prohibited. The technology allows healthcare practitioners to use a variety of WiFi enabled portable and fixed devices.
Wireless applications can be categorised into a number of sub divisions:
- Diagnostic and disease management systems
- Disease management, drug delivery systems and remote patient monitoring
- Well-being and personalised care
- Personal emergency call systems
- Consultation and emergency scenarios
- Telemedicine including ambulance to hospital data transfer
- Assistive technologies
- Robotic medicine – remote controlled diagnostics/surgery
- Clinical workplace management
- Pharmacy management
- Laboratory information management systems
- Refrigerated storage monitoring
- Asset tracking with “WiFi Tags”
These applications may have emerged using wired connectivity but the wireless evolution has allowed certain elements to migrate to a wireless option.
Portable sensors that can be worn on a patient’s body and transmit critical data wirelessly to a monitoring device, have facilitated remote patient monitoring; the ones for common diseases like diabetes becoming smaller, less obtrusive, and easier to use. These Wi-Fi wireless sensors will associate with the nearest Access Point, at home or in a bio-medical facility and use it as a gateway to the local network or internet, creating a secure data path to the application computer which generates a web page to provide authorised access to the data. Application computers may be in the same building as the local network or located somewhere else on the Internet.
Wireless technologies have matured to the point that they now provide a viable means for cost-effectively enabling many important medical applications with the necessary security to meet designated standards.
Hospitals once skeptical of using wireless technology, fearing interference from visitors’ mobile phones have had these fears proven to be unfounded. Patient records, voice calls, X-rays, scans and videos can be easily transmitted wirelessly – so why not other data from the laboratories?
“Wireless is quickly becoming the preferred option unless wired is needed. Wired used to be the preference for medical device network communication,” said Gary Hotine, HIS Director of South Devon Health Informatics Service. ”Wireless is definitely the future, wired is seen as the back-up provision over the longer term.”
Veracity Group Inc. one of the original creators of wireless systems has integrated all the benefits of modern WiFi in the development of its new VersaTrak WiFi monitoring system. Enabling hospitals and laboratories to meet the strict guidelines on the refrigerated storage of blood, vaccines and perishable medical products as well as enhance patient safety, VersaTrak Wi-Fi monitoring system reliably records the storage conditions in fridges, incubators and freezers as well as blood, tissue samples, specimens or drugs in transit.
The software continuously logs this critical data in real time, using calibrated sensors that communicate over the hospital’s Wi-Fi network. Information is easily accessed via an intuitive web-based user interface, accessing a local central database and is capable of monitoring one or multiple readings of temperature, relative humidity, differential pressure, door status and CO2 levels.
Using ultra-low power, battery operated transmitters, these discrete modules support up to three channels of data input with integrated IEEE 802.11.g radios. All devices include on-board data logging in non-volatile memory as a back up to network failures. Local audible and visual alarms alert staff of threshold breaches at the point of measurement as well as via the software application.
Frequent data sampling can be achieved (< 2 minutes) within the intelligent sensor while scheduled data transmissions of the stored data over the WiFi network to the application software, optimising battery life while ensuring exceptional measurements are transmitted immediately triggering local and networked alarms.
Bi-directional communication using WiFi between sensor and software has allowed the development of a unique patented technology for automatic calibration checking using four integrated certified reference points. VersaTrak will automatically run the scheduled “validation” and generate a report, showing all the test data from each transmitter creating a certificate that can be printed if necessary.
Each sensor has an on board clock that allows it to spend most of the time in a low power quiescent state, preserving battery life. Upon power up the sensor scans all available WiFi network channels (typically 1, 6, and 11) and associates with an Industry Standard Access Point exhibiting the strongest signal, provided the correct security (WPA2-PSK(AES) settings agree.
The 802.11 “Integration Strategy” reduces installation and on-going maintenance costs associated with the usual “Overlay Strategy” of installing yet another wireless network where one already exists. There is no need for base stations or repeaters typically required for most non-WiFi wireless systems
Designed to leverage the proliferation of 802.11 infrastructures in healthcare and biomedical facilities, VersaTrak enables IT Managers to derive added value from their WiFi Network while preventing wastage of product and staff time when using a manual system.
Any device that requires plugs and running wires can cost thousands before it can be implemented. “WiFi enabled” only requires a collection of optimally positioned hot spots and since most hospitals already have them their capital cost is minimal. As a result, excitement within the profession for wireless applications continues to grow.
Author: Jim Dryburgh, Veracity Group