Wednesday, December 26, 2007

Safe Wireless Practices

Many of us consider wireless devices to be enablers that make our jobs possible. I'm a Blackberry Advocate, carrying my 8707G or 8820 from the Board room to the top of Mt. Fuji.

However, are wireless devices safe to use in hospitals? Many hospitals have signs "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 5 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 wifi/cellular/bluetooth technologies in hospitals. The policy we issued is here, concluding 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 sigificant electromagnetic interference. Feel free to use these policies in your hospital if they are useful to you.

Although the 36 inch rule works well for patients, we have not yet answered what happens when you keep laptop with wifi 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, 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 3 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.

1 comment:

Matt said...

My sister who is hearing impaired was home for the holidays. She has a T-Mobile Sidekick for text messaging purposes, and I doubt she ever goes a 5 minute period without texting at least once. Having that device around, it's funny to here how many TV's, radios, and other devices it will cause interference with. It's seems to always make something buzz.

I know those cheaper electronics receive that interference because of unshielded internal cables and such, I would still be weary about having it near my IV pump though.

When you get some word on the whole laptop in your lap for long hours, let me know. Since I got my mac book back in October, I've started a nightly habit of reading news and such on it in bed for about 30 minutes before i go to sleep. The thought of the heat / radiation has crossed my mind before.