Reducing variations in power output measurements of electrosurgical devices

An interlaboratory comparison of test results on a common set of electrosurgical devices showed power measurements varied as much as 30%. The primary source of this variation is the reactances in the patient cables used to couple the output of the device to the standard test loads. Transmission line theory predicts, and empirical results demonstrate, that power measurement variation can be reduced by matching cable impedances to test loads or by using cables that are sufficiently short to minimize cable reactances.