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ESU-X 500TT_EN B
01.06.15
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INTRODUCTION AND DIRECTIONS OF USE - Physical and electrical principles
of HF currents
– Related risks
When electrical currents flow across biological tissues, they produce 3 effects: Electrolytic, Faradic and Thermal.
By applying a current, with frequency higher than 300kHz (named HF current), the electrolytic / faradic
phenomena either disappear or are very limited and the thermal one remains. This effect is exploited to obtain the
desired surgical result; in fact when an electric current with such characteristics crosses with sufficient density the
cellular liquid of the tissues, it warms it and generates what follows:
A heating so rapid that the vapor pressure into the internal and external liquids of cells breaks their
membranes and provokes their division: Pure Cut;
A heating, slower, which permits to the liquid to evaporate very slowly; in this way, the coagulating parts
of the tissues can coagulate: Coagulation;
A process which is in the middle between the two phenomena described above: Coagulating Cut.
This device allows the use of the HF currents in 2 ways - MONOPOLAR MODE AND BIPOLAR MODE.
MONOPOLAR MODE
This mode requires the use of two electrodes (the active one, small and used on the point of operation; the
neutral one, large and fixed on a different part of the patient’s body) and the current flows from the active to the
neutral electrode. The thermal effect affects all tissues included between electrodes.
BIPOLAR MODE
Also this mode requires two electrodes, but they are included in the same instrument and are very closed. In this
case the thermal effect produced by the current affects only a very small quantity of tissues.
RISKS CAUSED BY THE USE OF HF CURRENTS
The HF surgical devices are basic to solve surgical needs, but the use of HF currents, mainly when the
monopolar mode is used, presents also some risks. Here under some examples are detailed: Burns, on the
patient’s tissues where the neutral electrode is placed, caused by not sufficient contact. Burns on the surgeon’s
hand when the insulation of the active electrodes/instruments is damaged); Severe burns of patients /users
caused by the ignition/explosion of flammable/explosive gases or substances. In fact the normal sparks
generated during the delivery of power can ignite them. Bad functioning of other devices (pace
‐
maker, video
systems) provoked by EMC interferences emitted during the delivery of the HF currents;
Damages of the patient’s
tissues caused by a delivery of too high powers. Slight neuromuscular stimulation, notably while using currents for
coagulation, where the active electrode and neutral one are used. This stimulation can be felt by patients or
surgeons like “an electrical discharge”.
DIRECTIONS FOR USE
These devices allow the surgeons to perform the following
During operations of major or medium surgery (Open Surgery, Laparoscopy/MIS, Endoscopic Surgery) in O.T. or
equivalent places: Monopolar Cut (Pure or Coagulating), Monopolar Coagulation (low, medium and high voltage),
Bipolar Cut, Bipolar Coagulation (Micro, Macro, Sealing of vessels and so on).