Studies of temperature elevation under pediatric dispersive electrodes

The thermal performance of two commercial pediatric dispersive electrodes (Polyhesive II E7510 and Scotchplate 1148) were evaluated by infrared thermography, using a KCl-agarose block as a test medium to simulate human tissue. Values for delta T, the maximum temperature rise under the surface of the electrode, were similar for the two electrodes: 0.6-0.7 degrees C, 2.8-3.0 degrees C and 5.2-6.0 degrees C for currents of 1 A, 2 A and 3 A, respectively, applied to for 60 s. Reducing the contact area between the E7510 electrode and the test medium by 25%, 40%, 50%, 60% and 67% gave delta Ts of 0.5, 1.0, 1.3, 1.8, and 2.4 degrees C, respectively. The loss of water from the adhesive material of the E7510 electrode produced the expected increase in delta T and impedance (Z). Water losses of 0%, 15%, 34% and 50% gave delta Ts of 0.6, 0.9, 1.7 and 5.0 degrees C respectively. A 100- Omega increase in Z increased delta T by 3.5 degrees C (regression coefficient=0.96, n=35).<>