The misuse of high impedance electrode gels for defibrillation: a potential fire hazard

Seven different electrode gels commonly used in hospitals were tested by repeatedly delivering 360 J through a test fixture containing the gel into a 50-Ω load. A wide difference was observed in the performance among gels. Gels that had an initially low impedance (40 Ω) in the test fixture not only allowed a higher current flow, but also did not experience any significant temperature rise during the 15-discharge series, performed over a 7-min interval. Gels that had higher initial impedance (60 Ω) heated to more than 125°F, in addition to attenuating the current flow, and sparking was produced in the fixture. Because high-impedance gels result in significantly lower delivered current, their use may limit the effectiveness of cardiac defibrillation attempts. Further, the common belief that burns at the chest-paddle interface are a normal, although unpredictable, occurrence is now in question. Perhaps most important, the potential for spark generation during defibrillation in the presence of oxygen is clearly dangerous