Evaluation of the Electromagnetic Compatibility of WiFi Technology with Life-Supporting Medical Devices

Electromagnetic interference (EMI) to critical care medical devices has been deeply studied by the scientific community. Several papers demonstrated that medical devices are susceptible to EMI when exposed to particular types of RF sources and defined specific safety conditions that allow to minimize the risk of such an interference. These studies need continuous updates and revisions, in order to take into account the new technologies and to follow the technological development of medical devices, both as EMI sources or victims. The advantages that wireless mobility can provide to caregivers and other hospital staff, have led the Wireless Local Area Networks (WLANs) to be implemented in the hospital information and telecommunication infrastructures. In particular, the WiFi (Wireless Fidelity) standard has become the common solution to realize such a network. In this paper we investigated the EMI phenomenon on 44 critical care medical devices (infusion pumps, defibrillators, monitor, lung ventilators, anesthesia machines) by several types of WiFi terminals. The potential interference was evaluated by performing “ad-hoc” tests, according to the ANSI C63.18 standard. The behavior of the devices during the test was monitored using patient simulators/device testers, specific for each device class. EMI cases were observed on 3/44 devices tested. In only one case the interference caused a degradation of the basic performances of the device. Our finding show that the WiFi technology can be considered reasonably safe, although some interference may occur in case of direct contact between the WiFi source and the medical device.