Sept. 5, 2007 -- Dutch doctors today reminded hospital visitors to turn off their cell phones -- for the sake of health, not etiquette.
The reason: Cell phones may interfere with critical care equipment such as ventilators and external pacemakers, report the University of Amsterdam's Erik Jan van Lieshout, MD, and colleagues.
With that in mind, van Lieshout's team supports the practice of keeping cell phones at least a meter (about 3.28 feet) away from medical equipment or hospital beds.
That guideline "seems safe" but doesn't totally prevent the possibility of cell phones causing electromagnetic interference in hospital equipment, the researchers write.
They tested cell phones near 61 medical devices that weren't hooked up to patients.
In the tests, the cell phones caused 48 "incidents" in 26 devices. A third of those incidents were hazardous, such as totally switching off and restarting a mechanical ventilator, completely stopping syringe pumps without setting off an alarm, and causing incorrect pulses in an external pacemaker.
Another 42% of the incidents were classified as "significant" but not hazardous. Examples of significant incidents were incorrectly setting off an alarm or inaccurately monitoring blood pressure.
The remaining incidents were considered "light," such as disruptions of monitor displays that didn't require immediate attention.
The researchers note that their testing situations were "worst-case" scenarios. But they argue that their findings support restricting cell phone use in hospitals to areas where electromagnetic interference wouldn't be a problem.
The study appears online in the journal Critical Care.