Patient Return Electrodes

Ideal Return Electrode Contact with Current Dispersion

The ideal patient return electrode safely collects current delivered to the patient during electrosurgery and carries that current away. To eliminate the risk of current concentration, the pad should present a large low impedance contact area to the patient. Placement should be on conductive tissue that is close to the operative site.

Again, the only difference between the “active” electrode and the patient return electrode is their relative size and conductivity. Concentrate the electrons at the active electrode and high heat is produced. Disperse this same current over a comparatively large patient return electrode and little heat is produced.

Dangerous Return Electrode Contact with Current Concentration

If the surface area contact between the patient and the return electrode is reduced, or if the impedance of that contact is increased, a dangerous condition can develop. In the case of reduced contact area, the current flow is concentrated in a smaller area. As the current concentration increases, the temperature at the return electrode increases. If the temperature at the return electrode site increases enough, a patient burn may result. Surface area impedance can be compromised by: excessive hair, adipose tissue, bony prominences, fluid invasion, adhesive failure, scar tissue, and many other variables.

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