Electrical & Laser Safety Flashcards
The Law of Conservation of Electrical Charge states:
The total amount of electrical charge in the universe is constant. Charges are “simply” transferred.
Charges that move are what chemical species and what is their charge?
Negatively charged electrons.
What is electricity?
The flow of electrons - electron movement
All electrical charges have an associated:
force field
Stationary electric charges possess potential energy measured in joules. What is an example of a medical device that holds potential energy?
Defibrillator
What is a conductor?
Any substance that permits the flow of electrons. Most metals are due to mostly empty electron shells.
What is an insulator?
Any substance that does not allow the flow of electrons. Non-metallic.
Can insulators hold a charge?
Yes. It can hold a static charge. ex: defibrillator charging
What is an electrical current
The amount (magnitude) of charge flowing per unit time.
What is resistance in terms of electricity?
The energy required to push electrons through a material
What is an electrical circuit?
Electrical charge flowing through a closed path
What is a Direct Circuit (DC). Give an example
Current flows in one direction only.
Ex: Energy commonly battery powered
What is an Alternating Circuit (AC)
Give an example
Current periodically changes direction.
Ex: Derive energy from wall outlets or AC generators
Describe a Series Circuit
There is only one path that the current can take. Voltages and resistances are additive.
Describe a Parallel Circuit, give an example
Current can take more than one path. A unique current will flow through each resistor independently.
ex: household ciruits
What is electrical power?
Power is the rate at which energy is expended or consumed
What two variables impact Ohm’s Law
Resistance and Conductance
What does Ohm’s Law describe?
the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperatures remain constant.
Power consumed by am electrical circuit is measured in?
Watts
What is a semiconductor? What makes them “popular”?
Materials with conducting properties between those of insulators and conductors. The ability to control conductivity by the addition of small amounts of impurities “doping agents”
Semiconductors are most commonly prepared from?
Silicon
What are two types of semiconductors and what are they doped with?
P-Type: Positive type. Electron poor material composed of silicon and doped with Boron.
N-Type: Negative type. Electron rich material composed of silicon doped with Arsenic.
What are diodes?
Electrical current elements that have a large conductance in one direction and a smaller conductance in the reverse direction.
How is Spectroscopy used for in healthcare?
Analysis of blood work and oxygen pulse oximetry.
Substances in spectroscopy absorb complementary color, red absorbs??
Greeeeen
Beer’s Law describe the relationship between what three factors?
Absorptivity
Concentration of analyte
increasing the distance
What is transmittance?
Fraction of light passing through a sample. Influenced by intensity of the light.
What factors influence the strength of a shock?
The path of the current
The magnitude of the current
The duration of contact
What devices can produce an electric shock?
EVERY energized device or electrical circuit has the potential for producing an electric shock
What is a Macroshock
A relatively large amount of current flows through the body potentially resulting in injury or death
What is a Microshock?
A relatively small current is delivered externally and finds is way to the heart via a low-resistance pathway
A shock as little as _____ can casue ventricular fibrillation
100 uA
What are 3 modern electrical safety devices?
Polarized plugs
Three-pronged grounded plugs
Ground Fault Circuit Interrupters (GFCIs)
How do Fuses and Circuit Breakers provide safety?
Designed to prevent too much current from flowing because of a short circuit or circuit overlaid.
Fuse: contains a metal strip that heats up due to the resistance of the metal to the electrical current. If current exceeds the rated value of the fuse, metal strip will melt and stop current flow. Must be replaced.
Circuit: Same principle as fuse but metal bends instead of melts. Can be reset.
What are three items in the OR that use three-pronged plugs and grounded outlets?
IV pumps
Anesthesia Gas Machine
Cell Saver
Ground Fault Circuit Interrupters are usually used where?
Near water sources
To further reduce the likelihood of shock in the OR, most ORs use what kind of circuits?
Isolated Ungrounded Electrical Circuits
simply referred to as Isolated Circuits or Ungrounded Circuits
To make an Ungrounded Circuit, what is required?
An isolation transformer. Works through electromagnetic induction. No direct connection between the primary circuit [electrical source] and secondary circuit [site of electrical use].
What are Line Isolation Monitors
Indicates isolation circuit has been compromised. However, allows circuit to remain functional.
How do you identify the faulty piece of equipment setting off the line isolation monitor?
Sequentially unplugging one piece of equipment at a time until the indicated current on the LIM drops below the limit and silences.
What are the two types of Electrosurgery methods
Unipolar: requires grounding pad to complete circuit. Current passes through the body to grounding pad.
Bipolar: Utilizes two closest-spaced electrodes. Current flows between them and not through the rest of the body.
Thermal destruction of tissue through ESU creates what % of air contaminants
95% water
5% particulate matter, volatile gases, and microorganisms.
CO2 lasers produce contaminants equal to 3-6 cigarettes by burning how much tissue?
Only 1 gram!
Pacemakers are an electrical shock risk. What should be placed on them during surgery?
Magnet. Interrogate before and after surgery.
