EN‐10
MA510a_EN
Instruction’sManual
Accordingtothecometemperatureandinfunctionofusedpulseform,it’s
possible to recognize many types of effects produced by the current in
radiofrequencyonthehumanbody:
Coagulation
Temperatures from 60 to 70 ºC in the area around the active electrode
causeaslowheatingofintra‐cellularliquid
,thewatercontainedinthecell
evaporates and an action of coagulum is obtained, so the blood flow is
stopped.
Cut
Temperature over 100 ºC in the area around the active electrode
determines the evaporation of the intracellular liquid and the cell
explosion. The vapor around the electrode baits a chain reaction in the
direction where the acti
ve electrode is worked, transmitting the
evaporationenergytothetissuesaroundit.
Thecutisn’t,forthis,amechanicalresection.Ifthetemperaturecomesto
500°Cit’sverifythetissuewithanactionofcauterization.
Mixedcurrents
Theyareobtainedbythemi
xingofcoagulationandcuteffects.Thereisa
reductionofbloodlossduringthecutprocedure,orlikecutthatdevelops
asubstantialescharcoat.
The high frequency used by electrosurgical needle, don’t allow to the
electromagneticfieldtopenetratedeeplyinthematterandsothecurrent
crosses the c
onductor mostly in the external surface, reduces in an
exponential way and becomes negligible in the centre of the conductor
section. This effect, called ‘skin‐effect’ cause a reduction of the useful
sectionforthecurrentpassage,anincreaseoftheelectricalresistanceand
becomes an important problem in th
e neutral electrode. In fact in this
electrodethecurrentdensityisveryhigh(KA/m
2
)ontheedge,wherethe
excessive increase of temperature by Joule effect causes burns for the
patient. So it isn’t accidental that the burns for the patient, during the
electrosurgical interventations, have the shape of the edge neutral
electrode. To reduce the burns risk have to dose opportunely the supply
power (I
2
·t) and to follow the rules for the application of the neutral
electrodeonthepatient(seecap.SAFETY).
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