Interference/Cell phone
Joanne Kocourek (jskocour(AT)midway.uchicago.edu)
Thu, 19 Mar 1998 07:59:58 -0600
The types of interference we experienced with medical equipment that was
directly linked to cellular phone use were: The NEV100: 1) reprogramming of
ventilator parameters without human involvement (rate/pressure). This was
really strange as with the NEV100 one must "unlock" a security screen to
enter the panel which allows you to change parameters. 2) failure of
ventilator to ventilate with screen message that read, "internal system
failure, call for service". With the apnea monitor/pulse oximeter: 1)
complete failure to sense patient pulse, 2) audible alarms with sats/rates
within the appropriate parameters, 3) sensing of a heart and/or respiratory
rate that were NOT in sync with the patients actual rate 4) failure to
sense any heart or respiratory rate when they were present. In a period of
one month our DME company swapped a total of THREE ventilators, FOUR apnea
monitors and THREE pulse oximeters due to apparent equipment failure. The
manufacturers could not identify the cause of the problems within the
equipment and suspected RF interference. The next step was to check the
environment for RF interference which was done by four independent sources,
ie village, ComEd, and two independent contractors specializing in RF
problems. During one of th e"contractor" visits, our neighbor was in the
driveway (her back door) outside the girls bedroom on their cellular phone.
Each of those pieces of equipment demonstrated a malfunction at that time
(working properly immediatly prior in the presence of the inspector).
Their cell phone was the only identified cause of the difficulties. We
explained to our neighbors what was occuring and they kindly agreed to
maintain a distance of 30 feet or greater from the girls room when using
the phone. We have not had a singl;e problem since.
Joanne Kocourek
The University of Chicago
jskocour(AT)midway.uchicago.edu