by gnomey


keywords:
Bookmark and Share



Front Back
What type of power systems are used in the OR to reduce potential of electrical shock?
Isolated power systems
What is the definition of current?
Flow of electrons or electrical charge during a period of time.

Measured in amps
Types of current?
Direct Current- electrons flow in one direction

Alternating Current- Electrons oscillate and reverse direction of flow multiple times per second
how is alternating current measured?
measured in units, called Hertz

ie 120 volts at 60Hz, means that 120 volts of energy (force of push) oscillitates 60 times per second (i think)
what is voltage?
that amount of force or push that allows electrons to travel from atom to atom
Is impedence restriction or conduction?
Imedence is resriction.

It is the force opposing flow of electrons, is measured in ohms.

low ohms means less of an opposing force to the flow of electrons
What are examples of good conductors used in anesthesia?
metal
water
what does an insulator do?
it is a material that electricity moves slowly through. since electrons move slowly through the "insulator" then more electrons stay in the original pathway.

prevents leakage of electrons
is leakage from electrical equipment dangerous?
yes, if a piece of electrical equiment allows the unddesirable release of electrons into the environment
What is a watt?
measurement of the electrical work

voltage (push needed) x amps (amount of electrons that flow in a period of time) = watts (amount of work that needs to be done)

low wattage means low amount of energy that needs to be used to work.
what is the source of electrons? why is this important?
The ground is the source of electrons

The electrons want to return home
How is heat created with electricity?
the heat created is a byproduct of the work that a current of electrons has to go through to pass through a resistance

High resistance and fast current= High heat
At what frequency of electron movement are muscles and tendons susceptible to injury?
60Hz

At what kHz does nerve and muscle stimulation cease?
100kHz

surgery can be performed above this level
At what amp is electrical current first felt? when doe it cause pain? cause sustained muscle contraction?
5mA

pain->5 mA

sustained muscle contraction -> 10-20mA
at what amp does V-Fib occur?
100-300 mA
what is macro shock?
refers to the cardiac effect of an electrical current applied to intact skin

electrical current must travel through all layers of skin
what is micro shock?
refers to the effect of a small mount of current when applied directly to the myocardium via intracardiac catheters or wire

what is the differnce between milliamps and microamps needed to cause v-fib?
100-300 mA (milliamps) (can be applied to skin)

100 microamps (need to be directly applied to heart)
what is an isolated power system?
power is converted to ungrounded power, does not return to ground
since power sources in the OR are isolated power systems is there a reduced risk for microshock? macroshock?
Reduce risk of macroschock because of warning of leakage >2mA

No reduced risk of microshock, there may be leakage of 100 microamps
what should you do if the alarm sounds on a line isolation monitor (LIM)?
1. unplug most recently plugged in piece of equipment, if it stll alarms unplug non-essential items one at a time
why doesn't a body respond to the high Hz delivered by an ESU?
body cannot sense the high frequency, may cause tissue damage, but not v-fib
what does a monopolar electrosurgery tool do?
creates a a small and high area of current density at the tip. the heat produced by the high current can burn or vaporize tissue
what is different between the cutting and coagulation modes of ESU devices?
coagulation: thermal sealing of vessels

cutting: production of high temps that explode cells that contact electrode
are dispersive pads necessary with monopolar devices? bipolar devices?
monopolar- yes, electrons need a return point

bipolar- no, the insturment returns electrons to the ground
what are the 3 components of the fire triangle? are they all needed for a fire?
Fire triangle
1. fuel source (plastic)
2. ignition source (spark)
3. oxygen source (maintainer)

all 3 are need for fire to start
x of y cards