Environmental Safety

Question 0

Define voltage.

Answer 0

The pressure pushing electrons

*compares to contractility of the heart in the circulatory system

Question 1

What is the normal frequency used for alternating current (AC) around the world?

Answer 1

60 Hz

Question 2

Define circuit.

Answer 2

Path that current flows through.

*Similar to the blood vessels of the circulatory system

Question 3

Define ohm.

Answer 3

The measure of resistance (skin)

*similar to SVR in the circulatory system

Question 4

Define hertz.

Answer 4

Number of cycles per second

*similar to heart rate

Question 5

Define Amps.

Answer 5

The amount of current flow per second

*similar to cardiac index

Question 6

Define current.

Answer 6

The flow of electrical charges (electrons)

*compares to blood flow in the circulatory system

Question 7

Describe frequency.

Answer 7

• measured in Hertz (Hz)
• the higher the frequency, the less dangerous
• frequencies between 0-1 Hz can interfere with depolarization and repolarization in the myocardium causing arrhythmias
• frequency at which minimum current induces fibrillation is 50-60 Hz which is the normal AC frequency used worldwide

Question 8

Describe alternating current (AC).

Answer 8

• variation in electron density within the conductor is time dependent
• intermittent current

Ex: 60 Hz means the current goes from high electron density to low electron density back to high in approx 1/60 sec or 60 times per second

Question 9

Define conductor.

Answer 9

Material that current moves through easily

• good conductors are copper and bronze
• water is a great conductor

Question 10

Define insulator.

Answer 10

Substance/material that current moves through poorly

ex: glass and air are poor conductors
* skin is a poor conductor

Question 11

Describe skin as a conductor.

Answer 11

• skin is very resistant to current flow and a poor conductor
• as current flows through skin, resistance decreases
• dry, healthy, intact skin is 1 million ohms
• perspiring, intact skin is 12,000 ohms
• conducting jelly decreases skin ohms to 1,000
• catheter/pacing wires bypass the skin and go into the body fluid decreasing ohms to <100

Question 12

How does electricity work?

Answer 12

A specific amount of alternating current (amp) is pushed through a circuit by voltage (120v) at a specified frequency (60 Hz)

Question 13

Describe current flow.

Answer 13

• Current can flow through an unbroken closed circuit

- travels the path of least resistance

Question 14

Describe electrical resistance.

Answer 14

• impedance of flow
• can lead to storage of charges (capacitor)
• long power cords cause higher resistance *leading to pressure build up and current leaks

Question 15

Describe leakage current.

Answer 15

Current can escape the designated circuit and travel an alternative path

• high resistance can lead to leakage current due to excess pressure in the circuit and the currents desire to escape to a path of lower resistance and pressure

Question 16

Define current density.

Answer 16

The amount of current and area it flows over.

*similar to HCT or viscosity

Question 17

What are the three wires of a circuit?

Answer 17

• hot wire: supplies the current
• neutral wire: provides a return path
• ground wire: provides a low resistance path for leakage current to flow away from electrical equipment

Question 18

What is the function of a circuit breaker?

Answer 18

To interrupt the circuit when current flow is too high

-protects from overheating and fire

Question 19

Describe microshock.

Answer 19

• current is applied directly to heart
• small amounts of voltage or current applied directly to myocardium bypassing skin via IV cath, pacer wires, etc
• current as little as 100 micro amps can cause fatal arrhythmias

Question 20

Describe macroshock.

Answer 20

• current is applied directly to the body surface
• requires a large amount of current to overcome skin’s resistance
• can cause muscle contraction, pain, burns, open wounds, pacer disruption, arrhythmias

Question 21

What effects can 100-2500 milliamps at 60 Hz have?

Answer 21

V-fib

Question 22

What effects can over 6,000 milliamps at 60Hz have?

Answer 22

• sustained myocardial contraction
• respiratory paralysis
• burns if the current density is high

Question 23

What effect can 50-100 milliamps at 60 Hz have?

Answer 23

• pain

- mechanical injury

Question 24

What is the function of the line isolation monitor (LIM)?

Answer 24

- measures current flowing out and in, determining the difference or the amount of current leaking - alarm indicates current is no longer isolated and unsafe leakage current may be present * usually indicates either the last piece of equipment plugged in may have a fault or too much equipment is being used simultaneously resulting in too much leakage current

Question 25

Describe electrosurgical units (ESU).

Answer 25

- electrical current used to cauterize vessels and cut tissue - uses high frequencies between 300 kHz and 2MHz - two type: unipolar and bipolar

Question 26

Describe unipolar ESU.

Answer 26

The current is applied using a single electrode that returns to the ESU by way of a dispersal pad (Bovie or grounding pad)

Question 27

Describe bipolar ESU.

Answer 27

-involves use of a two pronged cutting electrode instrument -the current travels only between the two prongs *used when unipolar is unsafe: brain, ovarian, Fallopian tube surgeries

Question 28

Describe a dispersal pad.

Answer 28

- Bovie or grounding pad - should be applied as close as possible to surgical site, large surface area to minimize current density - pad must be in good contact - takes current back to Bovie box

Question 29

What effects can ESU have on pacemakers?

Answer 29

- ESU current traveling through pacer can alter functioning - pacer can be tricked if the current flows through the pacer and it will not pace * if 100% paced, the patient will go asystole * Place the Bovie pad close to the surgical site * Use a bipolar cautery * magnet may be needed- causes pacer to go into an asynchronous mode and it will fire without sensing

Question 30

What effects do ESU have on automatic implantable cardiac defibrillators (AICD)?

Answer 30

The ESU current will trigger the AICD to fire so the device should be turned off prior to surgery

Question 31

How far should the surgical site be from the pacemaker?

Answer 31

Beyond 15 cm

Question 32

Define antiseptics.

Answer 32

Antibacterial agents applied to living tissue

Question 33

Define disinfectants.

Answer 33

Antibacterial agents applied to non-living objects

Question 34

Describe hydrogen peroxide.

Answer 34

An antiseptic for skin *if splashed in the eyes may cause corneal ulceration

Question 35

Describe iodine.

Answer 35

Antiseptic used on skin * if splashed in the eyes, may cause irritation * if a facial surgery and site cleansed with iodine, first border the patient's eyes with saline or petroleum gauze to protect

Question 36

Describe chlorhexidine.

Answer 36

Antiseptic to clean skin *if splashed in the the eye can cause keratitis or loss of vision

Question 37

Describe chlorine bleach.

Answer 37

Disinfectant *vapors may irritate the respiratory tract

Question 38

Describe ammonia.

Answer 38

Disinfectant *vapors irritate eyes and respiratory tract

Question 39

What are some potential hazards in the OR?

Answer 39

Back strain Falls Contamination with infectious materials