Tissue Effects Change as You Modify the Waveform
Electrosurgical generators are able to produce a variety of electrical waveforms. As waveforms change, so will the corresponding tissue effects. Using a constant waveform, like “cut,” the surgeon is able to vaporize or cut tissue. This waveform produces heat very rapidly.
Using an intermittent waveform, like “coagulation,” causes the generator to modify the waveform so that the duty cycle (on time) is reduced. This interrupted waveform will produce less heat. Instead of tissue vaporization, a coagulum is produced.
A “blended current” is not a mixture of both cutting and coagulation current but rather a modification of the duty cycle. As you go from Blend 1 to Blend 3 the duty cycle is progressively reduced. A lower duty cycle produces less heat. Consequently, Blend 1 is able to vaporize tissue with minimal hemostasis whereas Blend 3 is less effective at cutting but has maximum hemostasis.
The only variable that determines whether one waveform vaporizes tissue and another produces a coagulum is the rate at which heat is produced. High heat produced rapidly causes vaporization. Low heat produced more slowly creates a coagulum. Any one of the five waveforms can accomplish both tasks by modifying the variables that impact tissue effect.