New research from scientists in the UK suggests that electromagnetic radiation from portable suction devices could interfere with some defibrillators, rendering them inoperable in a medical emergency.
According to Siu-Man Lee, Ph.D. from the Royal United Hospital Bath, Philips HeartStart MRx defibrillators are known to fail without warning during battery power operation if subjected to high electromagnetic interference (EMI). Used on resuscitation trolleys, defibrillators and other emergency medical devices are only required to be immune to 10 V/m interference levels.
However, upon examining other equipment on the trolleys, Lee and his colleagues found that Laerdal LSU 4000 portable suction units emitted EMI with field strengths up to 180 V/m, putting the defibrillators at risk for malfunction. Researchers also observed the field strength of the suction units dropped below this level at 1 meter, but concluded within that distance any electrical medical equipment could be susceptible to EMI. Their research is published in the publication Resuscitation Journal.
While researchers have not thus far tested whether the suction units actually interfere with the defibrillators or other equipment, Lee plans to in the near future.
“I have now received information from a ward in our hospital that the staff reported defibrillator malfunction in a training session,” he told Reuters Health via email. “Their defibrillator was on the wrong side of the suction unit at the time.”
“The main [reason for this study] is to alert healthcare professionals to avoid possible defibrillator malfunction from the EMF radiated by the suction unit. Also, be vigilant about the effects of the EMF from the suction unit because the EMF level is very high from the suction unit at close distance. Any electronic/electrical equipment can be susceptible under this level of EMF.”
When asked about his communication with portable suction unit manufacturer Laerdal, he said that the company has thus far decided not to take action, adding “they insist that the suction unit complies with all the current standards and regulations.”
“In addition, they pointed out that there is an instruction in the user manual, asking the user not to use their product adjacent to or stacked onto other medical equipment. However, this may not be always practical, especially for defibrillator and suction units, which are very often used together at the same time. In an emergency situation, it is not practical to ask the user to make sure certain medical equipment (is) at a very specific position, while all focus is on the patient. Also, the manual did not specify what distance is the ‘safe distance,'” Lee said in his email to Reuters Health.
“The manufacturer has the right not to do anything about this situation as they claimed that their product complies with all the standards (mainly BS EN 60601-1-2:2007 which is related to this situation). In this case, it is the standards which fail the consumers, by not specifying the product safety test that reflects the practical situation. However, this is a much longer story.”
“Nevertheless, it is worth noting that the defibrillator manufacturer, Philips Healthcare has issued a product correction notice on the 27th February 2014, they offer to replace all the batteries which can be susceptible to EMF.”
