Welch Allyn Electrosurgical Unit - User Manual - Manual (Page 8)

7
1. SETTING THE CONTROLS
a. Electrosurgical Tissue Effect
Delivery of continuous sinusoid waveform currents through a small elec-
trode at appropriate power levels can cause rapid heating of the intracellu-
lar fluids in the cells in close proximity to the electrode, turning these fluids
to steam. The significant increase in volume (approximately 5 times) caus-
es cellular structure to rupture, creating the clinical effect of “CUT”, with lit-
tle or no hemostatic effect along the margin of the divided tissue. Delivery
of short duration pulses of RF currents through a small electrode at appro-
priate power levels can cause heating of intracellular fluids at a more grad-
ual pace. This allows evaporation of these fluids without rupturing the cel-
lular structure, creating the clinical effect of desiccation, or “COAG”, without
the division of tissue. By varying the pulse to an intermediate duration, it is
possible to get a clinical effect that combines, or “blends”, the clinical char-
acteristics of CUT and COAG yielding the effect referred to as “BLEND”,
where tissue is divided with a desirable amount of hemostatis along the
margins of the divided tissue.
The electrosurgical effect may vary throughout the procedure, requiring the
operator to adjust the relative power setting of the generator.
b. Select the output mode (i.e., “CUT”, “BLEND”, or “COAG”) by pushing the
corresponding buttons.
Output Mode Waveform Description General Effect
CUT Continuous 450 KHz sinusoid Cutting without Hemostatis
with minimal modulation
BLEND Interrupted 450 KHz sinusoid Cutting with minimal
intermediate duty cycle Hemostatis
COAG Bursts of 450 KHz sinusoid Coagulation without Cutting
short duty cycle
c. Set the level of output power (confirmed on the digital display) by using the
output power selector buttons as desired.
WARNING
The degree and speed of electrosurgical effect is largely dependent on Cur-
rent Density at the point of contact of the active electrode. Loop electro-
surgical excision procedure electrodes from other manufacturers may vary
in the diameter thickness, size and configuration of the cutting wire. This
may result in SIGNIFICANT changes in the electrosurgical effect at a given
output power level setting. The use of Welch Allyn Electrodes is recom-
mended.
I. PROFESSIONAL USE GUIDE (cont.)
Electrosurgical Unit • Instruction Manual