Many hospitals have signs like “turn off your cell phone” posted at their entrances. When I recently visited Addenbrookes hospital in Cambridge, UK, a cell phone detector picked up my wireless devices as I entered the hospital and I was asked to power them down.
There are anecdotal stores about wireless devices causing cardiac monitors to display inaccurate waveforms, IV pumps to discharge their medications, and even ventilators to malfunction. Many of these reports are linked to very high power radios such as five-watt security walkie-talkies and not the lower power digital cell phones we use today.
In 2001, I assembled 100 bioengineers to review the question of safety of Wi-Fi/cellular/Bluetooth technologies in hospitals. We concluded that the heat and radio power experienced by patients 36 inches from a modern digital device is biologically insignificant. Since 2002, we've allowed all modern digital devices in our hospital as long as the 36-inch rule is followed. We do not allow patient families to use random wireless devices in critical care units, since we do not know what kind of device they may have and we cannot reasonably inspect every device they own. It’s possible that a family member could have an old analog phone or walkie-talkie that could broadcast significant electromagnetic interference.
Although the 36-inch rule works well for patients, we have not yet answered what happens when you keep your laptop with Wi-Fi sitting over your reproductive organs for hours every day. What happens when you keep a cell phone transmitter against your ear for hours? Is it better to use a Bluetooth headset with your phone to minimize heating and radio effects on brain tissue? Of course, that generally means your phone is strapped to your belt, which puts the signal close to reproductive tissues.
I do not have the answers to any of these questions and the evidence from the literature that cell phones/wireless placed close to the body cause side effects is inconclusive. Recently, an engineer at Los Alamos sent me a link to the Bioinitiative (www.bioinitiative.org), which is a consortium investigating possible long-term effects of all the signals around us. Many studies have concluded safety, but as the radio signals around us increase there may be a reason to enforce some limits so that we do not all become saturated. In the meantime, I recommend moderation. In my Prius, my cell phone bonds to the car via Bluetooth and I keep the phone three feet from my body. I use wired connections with my laptop when possible. I generally use my mobile devices for data communications, which transmit in short bursts rather than voice, which is a continuous signal. A balanced use of wireless, while research continues into long-term effects works for me.
CareGroup guidelines for the management of wireless devices
About John D. Halamka
John, MD, MS is CIO of Harvard Medical School, CIO of CareGroup Health System, CIO of Beth Israel Deaconess Medical Center, Chairman of the New England Health Electronic Data Interchange Network (NEHEN), CIO of the Harvard Clinical Research Institute (HCRI) and an Associate Professor of Emergency Medicine at Harvard Medical School.