Electrosurgical Devices

Question 1

What is a surgery ?

Answer 1

A procedure that involves incision of a patients skin and/or the closure of a wound.

Question 1

What are the types of surgery ?

Answer 1

Exploratory - Diagnosis of a condition
Therapeutic - Treatment or transplant surgery
Cosmetic - to improve appearance
Cardiac - heart surgery
Gastrointestinal - surgery relating to the digestive system
Orthopaedic - bone or muscle surgery

Question 2

What is the optimal humidity for surgery ?

Answer 2

50-60% rH

Question 3

What is electrocautery ?

Answer 3

Electrocautery uses a DC current to heat a heating element which burns the tissue by heat transfer. The current doesn’t enter the patients body and is supplied by battery powered

Question 4

What is electrosurgery ?

Answer 4

Electrosurgery uses an AC current and applies this directly to the tissue to perform a function.

Question 5

What are the 4 types of electrosurgical function ?

Answer 5

Cutting
Coagulation
Desiccation
Fulguration

Question 6

What are the components of an ESU ?

Answer 6

Foot pedals
Cords
An active electrode
A passive (patient return) electrode
A Radiofrequency generator ( 0.4MHz - 3.5 MHz)

Question 7

What are the 2 modes of ESU and what type of procedures are they used for ?

Answer 7

Monopolar - Consists of a grounding pad as the return electrode and incorporates the patient as part of the circuit. Monopolar uses large areas and frequently is used for coagulation.
Bipolar - The return electrode is within the surgical pencil. Bipolar are used in moist environments, delicate procedures or in proximity to pacemaker like devices

Question 8

What is coupling ?

Answer 8

the transfer of electrical energy from one part of the circuit to another

Question 9

What are the key parts of an ESU block diagram?

Answer 9

Power supply – > RF oscillator –> waveform selector –> Modulator –> Control circuit –> power amplifier –> coupling circuit –> electrodes

Question 10

What is the difference between mains power frequency and the power from an ESU ?

Answer 10

Mains - 50 to 60 Hz then the generator produces 200kHz AC current.

Question 11

What does a modulator do ?

Answer 11

Imposes an input signal onto a carrier wave which encodes the input wave

Question 12

What factors impact the tissue effect of electrosurgery ?

Answer 12

Waveform
Power setting
Size of electrode
Time of application
Type of tissue (including amount of dead tissue)

Question 13

What temperature causes instant cell death ?

Answer 13

> 60 degrees C
50-60 causes cell death within 1-6 minutes.

Question 14

Compare the safety of monopolar vs bipolar ESUs ?

Answer 14

Monopolar has a large chance of collateral damage through heat spreading.
Bipolar has a more localised collateral damage area and is usually applied over a smaller area.

Question 15

What are the waveform frequencies , voltage and thermal spread comparisons for cutting, fulguration and desiccation?

Answer 15

Cutting - a pure cut will have a high frequency waveform, a low voltage and a low thermal spread.
Fulguration and desiccation are types of coagulation which have a lower frequency waveform, a higher voltage and more thermal spread. Fulguration produces more sparking than desiccation and a bipolar device can only desiccate.

Question 16

What are some of the complication of electrosurgery ?

Answer 16

Direct application to the skin (movement from intended area)
Insulation failure
Direct coupling (contact with another electrode)
Capacitive coupling - due to poor conductivity of material, leads to a current build up before it reaches the electrode tip.

Question 17

What are some of the safety measures to prevent electrosurgical complications ?

Answer 17

Use the lowest possible power setting to achieve the result.
Do not use in open circuit or in close proximity to another instrument.
Use a low voltage (cut) waveform
Use intermittent activation where possible
Use bipolar where possible

Question 18

What maintenance checks and preventative maintenance is done on an ESU ?

Answer 18

Inspect Insulation and general condition of the unit.
RF leakage, return electrode monitor and power output tests.
Inspect the chassis, all cords and overall cleanliness of the ESU.
Check audibility of signals and verify waveform accuracy.

Question 19

What challenges can occur when servicing an electrosurgical device ?

Answer 19

Foot pedals - due to improper use or connections, damage or dirt.
REM - requires calibration to human skin and use of a simulator to test.
Touch pads
Electrodes
Interference

Question 20

What safety requirements are necessary for use of an ESU ?

Answer 20

Train staff properly
Install smoke evacuation system
Avoid skin to skin contact points
Avoid use around electrical equipment

Question 21

What are some examples of advancements in the electrosurgical device field ?

Answer 21

Argon beam - creates uniform bridge between electrode and skin and focuses current to reduce sparking and smoke plume.
Devices have been developed specifically for keyhole cautery surgeries
Ultrasonic energy can be used to power with vibrations of roughly 55,000 times per second providing as much energy as heat.
Some integrated the electrosurgical device into forceps or into saline delivery systems.
Some devices can use cryosurgery to remove skin lesions using opposite temperature principles to electrocautery.
Lasers and robotics have also had functions within this field.