Diagram for AED electrode placement.
Touted as life-saving devices, some 1.5 million automated external defibrillators (AEDs) are around the US. AEDs are designed to be used by anyone, regardless of training, to jumpstart the heart in a case of sudden cardiac arrest. And in this life-or-death situation, a surprisingly number of the devices fail.
Between 2005 and 2009, there were 28,000 reports of AED malfunction in the US, representing 1 out of 50 devices in the country. Mark Harris at IEEE Spectrum investigates the cause of these failures. Surprisingly basic engineering errors were responsible for some of the malfunctions, such as parts that are just too imprecise for a matter of life or death:
One AED, the brand name of which the FDA would not disclose, was found to occasionally misdiagnose the heart’s electrical rhythm. It delivered some shocks that weren’t needed and failed to deliver others that were. The culprit was a resistor that could vary in resistance by up to 10 percent of its stated value. “When our engineer looked at this design, it was an instant ‘uh‑oh,’ †says [Al Taylor of the FDA].
How could regulations on medical devices be so lax? …
from Discover Magazine