Topic 4.2

Question 1

If direct current (polarized, and not changing) or high frequency AC passes through the body what are it’s effects?

Answer 1

It will cause heating effects and ultimately burns
(used in electrosurgery to cut tissue or coagulate fluids)

Question 2

If Low frequency AC is applied to the body what are it’s effects?

Answer 2

1) muscular contraction and relaxation (polarisation/depolarisation)
2) Ventricle fibrillation
3) Death

Question 3

What is Marcoshock?

Answer 3

Macroshock is when large currents in milliamperes or larger is applied to the body from one external point to another external point ( electrode on hand to electrode on leg )

Question 4

What is Microshock

Answer 4

Microshock is when the current is in microamperes and it is applied to the body through invasive catheter or other invasive means. Because the conductive material bypasses the skin resistance, the resistance to the heart can be very low. Hence, lower current is required to be electrocuted.

Question 5

What is the Threshold of perception current?

Answer 5

1mA or Less

Question 6

at what current will it cause mild to painful sensation?

Answer 6

1mA or More

Question 7

at what current is the let-go current?

Answer 7

10mA or More

Question 8

At what Current is when respiratory paralysis occur?

Answer 8

20mA or More

Question 9

at what current is when ventricular fibrillation occur?

Answer 9

75mA or More

Question 10

at what current does paralyses of the heart and burning of tissues occur?

Answer 10

1A or More

Question 11

Microshock can have the same effects as Macroshock however it is smaller by how many times?

Answer 11

10,000 times smaller

Question 12

What is the standard for safe leakage current for manufacturers?

Answer 12

5mA

Question 13

What are the 7 Parameters that affect the Susceptibility of electric shock?

Answer 13

1) Threshold of perception (Different for both genders)
2) Let-go Currents (Different for both genders)
3) Duration (shock must last longer enough until the T-wave occurs to cause ventricle fibrillation)
4) Body Weight (Fat people more resistance hence need more current to die)
5) Point of Entry ( the 2 electrodes must be on different end of the body else low risk of fibrillation)
6) Frequency ( 10Hz and below the let go current increase 1kHz and above same thing high frequency used in electrosurgery)
7) Skin and Body Resistance

Question 14

What is the purpose of the grounding pad/ Patient Plate?

Answer 14

It is to return the electrical current from the patient back to the generator through a cable

Question 15

What is Monopolar electrosurgery technique?

Answer 15

it is the use of an active electrode to cut the patient tissue and also a dispersive electrode that safely take the current that passes through the body into the pad and away from the patient. improper adhesion of dispersive pad will cause electrode burns

Question 16

What is Bipolar electrosurgery technique?

Answer 16

Bipolar electrosurgery uses lower voltages and have limited cutting and coagulating ability for large areas and it is used to grab onto tissues by the forcep of the electrode. current only limited to tissues between forceps

Question 17

What are the 3 examples that will reduce/eliminate skin resistance making patient more vulnerable to electric shock?

Answer 17

1) Application of electrodes (Invasive electrode more Dangerous)
2) Intravenous Catheter that has conductive fluids
3) Electronic thermometers that is place in the mouth or rectum ( bypass skin resistance)

Question 18

what is current density?

Answer 18

Current density is the amount of current that the electrosurgical unit applies to the contact point over the cross sectional area of the dispersive electrode