Evaluating Electrosurgical Generator Performance

d03a.jpg (7313 bytes)Many electrosurgical generator choices are available, and there can be confusion when trying to determine which generator is most appropriate for the wide range of surgical procedures performed in today’s operating rooms. It often becomes an arduous process of weeding through technobabble and slick marketing to discover the most important clinical performance parameters. To aid in this decision-making process, a method of measuring generator performance has been developed. This method can be applied to any generator from any manufacturer and allows comparison on an even scale with one simple number. This number is the Power Efficiency Rating, or PER.

The Power Efficiency Rating predicts the output characteristics of an electrosurgical generator when an activated accessory is used under varying conditions. Specifically, PER measures the ability of an electrosurgical generator to accurately deliver the selected power into a wide range of impedance loads, representing differing tissue types.

Manufacturers often claim their generators adjust to changes in tissue impedance. However, it is important to differentiate between the speed at which tissue impedance is sensed and the generator’s ability to change output parameters, which can be modeled using the PER. There are generators that can rapidly sense tissue impedance, but may not adjust output in a manner that maintains a consistent clinical effect. Only by comparing PER values can you evaluate a generator’s clinical performance simply and consistently.

In clinical use, a generator with a low PER cannot deliver the power necessary when encountering high-impedance tissue such as fat, scar and adhesions. Variations in tissue impedance prohibit most generators from consistently delivering the selected power, and in practice, the operating room staff may resort to manually adjusting the output to compensate. This increased power can cause excessive damage to low impedance tissue such as muscle.

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