As wireless device use becomes an integral part of our daily lives, we are asking for fewer restrictions on their use in hospitals. Devices such as smart phones and tablets provide many potential benefits in this environment. Patients can use wireless devices to connect with friends and family or pass time in the waiting room, making their hospital visit a more positive experience. Clinicians can use wireless technology to do their work more efficiently — quickly consulting with other care providers, easily accessing information resources and electronic health records, and viewing and recording patient data on the spot. But, the potential for electromagnetic radiation generated by wireless devices to interfere with medical equipment remains a concern to patient safety.
In 2011, CADTH conducted an environmental scan of hospital policies on wireless device use. At that time most of the Canadian hospitals surveyed were either in the process of revising their policies or had revised them within the last three years. The newly implemented policies attempted to strike a balance between convenience and safety — limiting wireless device usage within a specific distance from medical equipment and prohibiting their use in patient care areas where medical equipment is heavily used, while allowing their use in hospital waiting areas, lounges, private offices, and cafeterias.
But are such restrictions actually required? What do we know about the interference to medical equipment caused by wireless devices and the extent to which this interference compromises patient safety?
To answer these questions, CADTH’s Rapid Response service undertook a review of the available evidence on the use of wireless devices in health care environments. The studies looked at several types of wireless devices — ultra-high frequency radios, various mobile phones, and a variety of Bluetooth-enabled devices — using a broad range of transmission technologies such as code division multiple access (CDMA), general packet radio service (GPRS), global system for mobile communication (GSM), Terrestrial Trunked Radio (TETRA), universal mobile telecommunications system (UMTS), wireless local area network (WLAN) and analog. The effect of these devices on the performance of several types of medical equipment was investigated in the studies, including defibrillators, ventilators, brain stimulators, pumps, and ophthalmic equipment.
The CADTH review found that electromagnetic emissions from wireless devices do frequently cause interference with medical equipment. This interference manifests itself in several ways — noises, screen distortions, false alarms, complete stoppages, and malfunctions in output parameters. Equipment is more likely to be affected if the wireless device is using the same radio frequency, transmitting a strong signal, or in close proximity to the equipment. Incidences of the interference affecting medical equipment to such an extent that it compromised patient safety were, however, found to be uncommon. When it did occur, the equipment and the wireless device were in very close proximity to one another — less than 3 feet apart.
However, the available evidence on this issue has limitations. Not all types of medical equipment were assessed, and there may be some equipment that is more susceptible to interference than those that were included in the studies. The technology used to design both wireless devices and medical equipment is constantly changing — in the near future it may create more interference or be more susceptible to interference than was the case at the time. Some of the studies were conducted with a single piece of equipment in the room, which may not be the case in every health care setting.
Even without these limitations, any risk of electromagnetic interference resulting in a malfunction in medical equipment exposing patients to risk of harm, misdiagnosis, or incorrect treatment is cause for concern. The unrestricted use of wireless devices in health care settings, therefore, cannot generally be considered to be a safe practice.
Given that the popularity of wireless devices among patients, visitors, and health care providers is here to stay and likely to continue increasing, there are measures that need to be taken to limit harm to patients. Hospitals are, and will continue to, develop policies to regulate wireless device use in highly instrumented areas to protect sensitive equipment from exposure to hazardous electromagnetic interference. And experts in these technologies can help hospitals select equipment that is less susceptible to interference from commonly used wireless devices. Such measures will protect patient safety while allowing for the continued use of wireless devices to benefit medical practice and improve convenience.
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