CAM Interactions

Cell phones affect hospital equipment

I previously posted that being without my cell phone stresses me out. So, in the spirit of cell phones as complementary medicine, I summarized the results of a Mayo Clinic study showing that cell phones did not affect hospital equipment.

In the interest of balance, here’s a study that concludes otherwise.

MedpageToday reports that Dr. Erik van Lieshout at the University of Amsterdam’s wanted to use 3G mobile phone technology to monitor mobile intensive care units remotely. Nobody knew if the device might interfere with the hospital equipment. So, he and his colleagues carried out the study.

First, the details.

  • They didn’t actually use cell phones.
  • Rather, they generated maximum mobile phone power signals using a signal generator.

And, the results.
There were 48 incidents in 26 devices: 16 (33%) classified as hazardous, 20 (42%) as significant, and 12 (25%) as light.

  • 9 hazardous events in 7 of 9 tested ventilators, ranging from switch-off and restart to changes in ventilation rate.
  • 2 hazardous events in 2 of 7 syringe pumps, including complete stops without an acoustic alarm or with an incorrect alarm.
  • 1 of 3 external pacemakers developed incorrect inhibition of the pacemaker.

The median (middle) distance between cell phone signal and device when interference occurred was 3 cm (about an inch). Although one incident took place when the signal was 500 cm (16 feet) from the device!

The bottom line?
Critical incidents were rare but could be “potentially lethal.” Therefore, Dr. van Lieshout proposes the one-meter rule, which recommends that mobile phones be used more than 3 feet from medical equipment — or not at all in patient areas, if possible.

The degree of risk seems to be related to the strength of the signal emitted by the cell phone. Newer models capable of greater signal strength pose greater risk, particularly in areas of poor cell service where the phones work harder to connect to the signal source.

9/8/07 11:25 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.