I work with the Life Options Rehabilitation Program and staff Life Option's Rehabilitation Resource Center. We have been encouraging clinics to provide opportunities for patients to do productive activities on dialysis. At least one dialysis corporation has reportedly prohibited patients from using cell phones and laptop computers on dialysis stating that it will interfere with the functioning of dialysis machines. I found this hard to believe since I knew patients that used cell phones in dialysis years ago, but I thought I'd ask the experts. Is this myth or fact?

If it is fact,
1) What brand of dialysis machines will be disturbed by either a cell phone or laptop computer?
2) Does it make any difference if the cell phone is analog or digital?
3) Does it make any difference if the computer is PC or Mac?
4) Does it make any difference how far away from the machine the "offending device" is?

Thanks so much for your help and advice?

Beth,

All electronics emit RF noise and have the potential to disrupt the clock cycles of a microprocessor. The severity of the disruption if any is dependent upon how well the microprocessor is shielded, the strength of the RF and its proximity to the microprocessor.

The Fresenius 2008H manual states that cell phones and other 2-way radios should not be used near the machine. The Althin System 1000 and Tina manuals do not address this at all and the Tech Service department at Baxter will not make a reccommendation one way or the other.

Beth,

This is the way it was explianed to me by someone in the know.

The issue is that a cell phone emits Radio Waves at a given Frequency. Electronic components also operate on their own frequencies. What could theoretically happen is that the electronic circuit could "latch on" to the Radio Wave Frequency. It could make electronic components run at incorrect clock speeds, affect logic calculations, etc.

Yes the chance is slim, but I have to support the cell phone ban.

A laptop computer running on a battery, not AC power, should be no problem. However, it should not be connected to a wireless network at the time.

TD

Though I have not seen or heard this reported recently it is a fact that emmissions from cell phones or other electronic devices could cause some type of interference with a machine. 3 quick stories:

1) If I have my cell phone near my PC I know when someone is calling me before the phone rings because the "pre-ring" signal causes a chatter sound on my computer. This also sometimes happens when I'm in the car and pass from one cell tower to another - the same type of static will come through the radio.

From the old days:

2) Had a unit with Cobe C2 RX machines. One day Mr. A was on dialysis and called Mrs. A on a regular phone - the machine went into high pH alarm. As soon as he hung up the alarm cleared itself. We had him call Mrs. A repeatedly while we tested different things -each time the same thing happened. Ultimately we determined that the pH monitor calibration was set too high and the phone signal was passing through the di-electric connection - patient to the machine via the dialysate - and increasing the pH probe voltage enough to trigger an alarm. Once we reset the pH cal voltage to its proper place no more alarms.

2) Dr H was very proud of his new unit with the then state of the art Gambro AK10's. On the second day of operation at about mid afternoon most of the machines simulataneously started alarming for no apparent reason - manufacturer ws called in and they declared RF inteference - you see Dr. H built his unit about a 1/2 mile from 6 TV and radio transmission towers set out in the marsh - the difference between the 1st day and 2nd day was, day 2 was a nice spring day and the staff decided to open the metal blinds on the windows - blinds down (shield) no alarms - blinds up (no shield) alarms. the RF interference was so bad that if you opened the outside door to the reuse room the DRS 4 would start alarming. Eventually the AK10's were swapped out for (of all things) Cobe C2Rx's and no more problems - and yes the door to the reuse room was kept closed. I suggested to Dr. H that we just wrap the building in tin foil - he did not see the humor in that!

So it is possible.

I have been in 3 units with 3 brands of machines. Cell phones and laptops were permitted in each one without any apparant problems.

I really appeciate everyone's responses. This is an area that I know absolutely nothing about.

I've seen signs in hospitals banning cell phones apparently because they can interfere with some equipment. However, I learned recently this policy was instituted when people were using analog phones and newer digital ones may not create this problem.

Airlines prohibit the use of cell phones, computers, or other electronic devices during take-off and landing because of possible interference. However, on 9/11/01, people on Flight 93 were using cell phones and no one has ever said that cell phone use had anything to do with the PA plane crash.

It sounds like it would be worthwhile to do a "study" to test today's cell phones and laptops -- with battery and with power cord -- while sitting in a dialysis chair next to the most commonly used dialysis machines to see if the newer models of these devices interfere with one another.

As an alternative, do you think cell phone and laptop manufacturers could let us know how much RF noise one of these devices currently puts out and that would tell us whether the problem is real or not?

Bottom line...I hate to see patients staring at the clock because they're banned from using these tools that could help them keep doing work for their jobs or occupy their time and enhance their lives if it's no longer a problem.

Here is something for you to try. If you are using the Cobe C3. With the blood pump running take your cell phone and hold it next to the ultrsonic air bubble dectector dial a number and press send. You will set off the Air in blood alarm. I can get this to happen every time. The Air bubble detector on the Cobe C3 uses sound to detect air. The transmitting side of the transducer is connected to a 2.5 megahertz oscillator circuit. The receiver looks for this singal if there is a change in the level of this singal the machine will set of the air in blood alarm. The RF from a cell phone at close range will interfere with this singal.

quote:

Originally posted by Beth Witten:
...
Bottom line...I hate to see patients staring at the clock because they're banned from using these tools that could help them keep doing work for their jobs or occupy their time and enhance their lives if it's no longer a problem.

Beth I couldn't agree more. I think that the worst-case effects of using an electronic device are not that serious, unless I missed something. The Northwest Kidney Centers provide patients with Internet access at each station and allow cell phones - NKC uses B Brauns and Cobe 3s. I think that before these items are banned there should be a clear threat identified. The isolation of incenter dialysis is a hardship that can be lessened with modern technology; I think banning these tools is a hasty reaction to theoretical and inconsequential concerns.



[This message has been edited by Bill Peckham (edited 02-14-2003).]