Wireless communication networks (WLAN) in the OR – a potential interference hazard for implantable electrical active devices?

Objective: With the rapid spread of wireless local area networks (WLAN) in OR's and other hospital areas, the question arises whether this radio based technology might compromise pacemaker- (PM) and implantable cardioverter defibrillator (ICD) function. Particularly with regard to US legal requirements (FCC) that enable higher transmitting power than european regulations (ETS), interference of conventional WLAN with PM and ICD has to be investigated.

Methods: In this experimental in-vitro study, we tested 30 PM and 25 ICD-models of several manufacturers with two WLAN-configurations (maximum transmitting power ETS 100 mW; FCC 1000 mW. WLAN-setups were tested with different distances of the antenna to the device and with several transmitting modes. Interference was rated according to type and significance in 3 classes.

Results: The incidence of any type of interference was 14.5%. There was no clinical significant class 1 or 2 interference (inhibition, reprogramming, safety pacing) with any PM or ICD. Less severe class 3 interference was observed in 8 PM and was limited to telemetry interference (noise artifacts, erroneous event markers) up to 60cm distance. Nevertheless, FCC WLAN radiation inhibited programming of emergency VVI-parameters in one PM.

Conclusions: Our study indicates that WLAN equipment in Europe and USA does not represent a significant risk to PM and ICD recipients. US WLAN can interfere with the function of PM-programmers and even disturb emergency telemetry. Therefore, legal operation of high-output access points is not recommended close to the operating table and in areas of follow-up of PM- and ICD-patients.