Utah Medical Products FINESSE +, Руководство по обслуживанию

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Service Manual
9
Principles of Electrosurgery
The system is a monopolar generator which produces the optimal waveforms for elec-
trosurgical cutting and coagulation. In monopolar electrosurgery, a radio frequency current is
passed through the body of the patient between an active electrode, where the current is very
concentrated, and a dispersive electrode, where the current is quite diffuse.
The active electrode is used as a cutting or coagulating tool at the site where surgery is to be per-
formed. The dispersive electrode is applied at a site away from the surgical field for the purpose
of returning current to the generator.
Electrosurgery results from the concentration of electrical energy in tissue to the point that the
tissue is locally destroyed or modified. In electrosurgical cutting, the cells conducting the concen-
trated current are heated to the point where the water contained inside the cells boils and the
cells explode to release steam. In electrosurgical coagulation, cells near the surface are heated so
that those not exploded are dehydrated and shrunk to the point where open vessels are closed.
Cutting
To obtain cutting with minimal heating, a tool with a small cross section, such as the thin-wire
loop, is driven with an electrical source having a continuous, unmodulated wave form. This kind
of power source is referred to as a pure cut source. Modulating or periodically interrupting the
voltage from the cutting source creates a current that will cause shallow surface coagulation as
well as cutting. This kind of source is called a blended source.
The system has a pure cut mode and three blended cut modes. The waveforms pro-
duced to provide these modes are described quantitatively in the
Technical Data
section of this
manual.
Coagulation
To obtain coagulation without cutting, an active electrode with a larger cross section, such as a
ball electrode, is usually used. A power source with a high voltage interrupted waveform is
applied to the active electrode.
Fulguration is accomplished using either a blunt or fine electrode with the coag mode waveform.
The active electrode is held slightly above the surface to be coagulated so that the sparks jump
across the gap. At the points on the surface where the sparks enter, very high current densities
are achieved and tissue is seared. However, the area of the surface contacted by the spark and
the current carried by each spark are small and the heat damage is quite shallow. This method
usually produces a good cosmetic result after healing is complete.