Electro surgical unit

1
Electro surgical unit
2
PURPOSE

• ESU are used for surgical cutting and for
  controlling bleeding by causing coagulation
  hemostasis at the surgical site.
• It is high frequency diathermy involves the
  transference of electrical energy into heat which
  ,when impact to the bodily tissues, will heat the
  normal cell fluid, eventually through it is
  boiling point.
• What dose DIATHERMY mean?
  
• DIA through
• THERMO temperature heat
  
  

3
Principle

• ESU machine is an alternating current source that
  operates at radio frequency RF.
• A high frequency current flowing through active
  electrode high current concentration.
• Cell ruptured-fumes or evaporates.
• Return path through dispersive electrode low
  current and heat dissipates.
• Patient is included in circuit.
• Current concentration or density depends on the
  size of the area through which the current flows.
• HF generation can be activated by a foot switch
  or finger switch on the surgical handle.

4
System Components
Electrosurgery Unit
Active Electrode
Dispersive Electrode
5
Active electrode
RF Generator
Body
Patient electrode
..\ESU Principle.ppt
6
(No Transcript)
7
Effect of RF on cell

• When a high frequency current applied to the
  tissues the tissues gets turn apart and get the
  following effect
• Thermal effect.
• Electrolytic effect.
• Faradic effect.

8
Operating frequency and typical value

• Operating frequency of solid state surgical
  diathermy machine is 300 KHz to-3MHz
• Monopolar CUT 0-to-350watts for load 5
  
  COAG0-to-100 watts
• Bipolar CUT 0-to-50 watts
• COAG 0-to-10 watts
  

9
Types of ESU

• Spark gap generator 1924
• Still in use today urology , open- heart
  surgery.
• Spark gap / vacuum-tube device use spark gap
  circuits to generate high frequency waveforms.
• It is not offer the same safety feature as solid
  state unites.

10
Recent technology

• Argon/argon enhanced technology.
• It uses a computer-controlled tissue feedback
  system that senses tissue impedance and
  automatically adjusts the current and output
  voltage to maintain a constant surgical effect .
• It is reduces the need to adjust power setting
  for different types of tissue.
• It is also gives improved performance at low
  power setting to reduce the risk of patient
  injury.

11
Solid state device - 1968

• It is more recent and more prevalently used
  technology.
• Contain oscillator circuits and transistor-based
  amplifier that vary the frequency and modify the
  shape of the line signal to create an array of
  different waveforms for pure CUT,COAG, BLEEND .
• Highly safety.

12
OK!, but how can I control so accurately the
temperatures in the tissues ?
13
Modes of Electro surgery

• 
  Monopolar
  surgery
• Bipolar surgery

14
Modes of electrosurgery

• Electrotomy/cutting
• desiccation / coagulation
• Blend
• fulgurations

15
General Block Diagram
Audio tone generator
Power supply
Logic/ Control Board Rely board
Main CPU
Front panel
Isolation transformer
LED display
Power O/P or RF board
Foot switch
Patient return electrode
RF output