Information technology

Mobiles phones dangerous near hospital beds

12 September 2007

Mobile phones should come no closer than one metre to hospital beds and equipment, according to research by the Academic Medical Centre of the University of Amsterdam and the Netherlands Organisation for Applied Scientific Research.

The study, published in Critical Care (1) showed that incidents of electromagnetic interference (EMI) from second and third-generation mobile phones occurred at a median distance of 3cm, but effects were observed up to 500cm from equipment.

In this particular study, the research team examined the effects of General Packet Radio Service (GPRS) and Universal Mobile Telecommunications System (UMTS) signals on critical-care equipment such as ventilators and pacemakers. Almost 50 EMI incidents were recorded: 75% were significant or hazardous. Hazardous incidents varied from a total switch off and restart of mechanical ventilator and complete stops without alarms in syringe pumps to incorrect pulsing by an external pacemaker.

Incidents were observed in a range of medical equipment: intensive care unit ventilator, critical care monitor, syringe pump, volumetric infusion pump, intra-aortic balloon pump, haemofiltration/dialysis, external pacemaker, defibrillator, 12-lead EKG, fluid warmer, enteral feeding pump, and air humidifier.

The second generation (2.5G) GPRS signal caused the highest number of EMI incidents at over 60% whereas the third generation (3G) UMTS signal was responsible for just 13%. EMI incidents also occurred a greater distance with GPRS, with a hazardous incident even at three meters.

While first-generation mobile phones are used mainly for voice transmission, 2.5G and 3G phones enable internet access, sending and receiving data. They entered the market, however, with little proof regarding their safe use in the medical environment.

Dr Erik van Lieshout, lead researcher from the Academic Medical Centre, University of Amsterdam, said; “Our work has real implications for present hospital restrictions of mobile phone use in patient areas.”

“It is unlikely that mobile phone induced EMI in hospitals will be eradicated in the near future so the one metre rule currently in place should continue, as it is relatively safe,” commented Dr van Lieshout.

Wireless technology is increasingly being used in hospitals to enhance patient care, eg intelligent pager systems with smart phones, personal digital assistants with internet access, and telemonitoring.

The researchers claim that the international standard on electromagnetic compatibility by the International Electrotechnical
Commission is insufficient to safeguard medical equipment completely from EMI by mobile phones, whether GSM, GPRS or UMTS, and that the present industrial standard lacks stipulations for eliminating EMI in medical equipment.


1. Erik Jan van Lieshout, Sabine N van der Veer, Reinout Hensbroek, Johanna C Korevaar, Margreeth B Vroom and Marcus J Schultz. Interference by new generations mobile phones on critical care medical equipment. Critical Care 2007, 11:R98.

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