Exam #3 Flashcards
1
Q
capacitance
A
the capacity to store electrical charge
2
Q
3 mechanisms of electrical shock in the OR
A
- direct wire contact with metal casing due to insulation damage or faulty construction
- inductance due to the magnetic field of the AC, producing a small electrical flow in the surrounding metal casing despite no direct contact
- stray capacitance from the buildup of electrical potentials with an AC circuit despite no closed circuit electrical flow.
3
Q
define DC circuit
A
direct current, flow of electrons in one direction
4
Q
define AC circuit
A
alternating circuit, flow of electrons reverses direction @ set frequency (60 Hz)
5
Q
what is the macroshock threshold for perception
A
1mA
6
Q
what is the macroshock number for loss of consciousness
A
50mA
7
Q
what is the macroshock number for vfib
A
100-300mA
8
Q
what is the macroshock number for “let go” current
A
10-20mA
9
Q
what is the microshock number for v-fib
A
100μA
10
Q
what is a transformer used for
A
isolate electrical supply systems from one another using the principle of magnetic inductance to transfer electricity from one system to another system without having physical contact
11
Q
magnetic inductance
A
the tendency of an electrical conductor to oppose a change in the electric current flowing through it. The electric current produces a magnetic field around the conductor
12
Q
why is the OR power supply ungrounded
A
to prevent shock if a person contacts one live wire
A person must contact both wires in a circuit for shock to occur as the path of electricity flows through the person from one line to the other
13
Q
why is OR equipment casing grounded
A
to divert electrical flow in case of internal live wire contact with the metal housing
14
Q
what is a line isolation monitor
A
device placed between the live wires and ground to measure their impedance to flow. Alarms if a live wire has contact or high capacitance to ground.
15
Q
what to do is a line isolation monitor alarms
A
disconnect the last piece of equipment plugged in and inspect it to verify that it is the offending piece of equipment. May also be activated because of the cumulative effect of minor leakages of many pieces of properly functioning electrical equipment but no risk present.
16
Q
what are line isolation monitors set to alarm at
A
2-5mA
17
Q
what does placing a magnet over a pacer do
A
reset to a continuous asynchronous mode (DOO, AOO, VOO)
18
Q
define photon
A
a particle representing a quantum of light or other electromagnetic radiation. No mass
19
Q
can EMR exist independently of matter
A
yes
20
Q
how does EMR interact with matter (4)
A
reflected
refracted (scatter)
diffracted (redirected)
absorbed (interfered)
21
Q
where do x-ray waves fall on the EMR spectrum
A
higher energy frequency
22
Q
3 factors of safety for x-rays
A
distance from source
barrier
exposure time
23
Q
minimum recommended distance from x-ray
A
6ft
24
Q
what type of fire risk is a laser
A
ignition
25
what type of fire risk are drapes, dressings, and linens
fuel
26
steps to take if an airway fire occurs (7)
stop o2 flow
stop ventilation
extubate
extinguish fire
mask ventilate
reintubate
bronch, lavage steroids
27
define electricity
change in potential energy caused by the movement of electrons from an area of high concentration to an area of low concentration
28
what is the SI unit for electric charge
coulomb
29
what is one coulomb
the amount of electric charge transported in one second by a steady current of one ampere
30
Coulomb's law
opposites attract, likes repel, neutrals don't interact with charges
closer the charges are, the stronger the force b/w them
31
Ohm's law
V=I*R
V= voltage
I= current
R= resistance
32
what is voltage in Ohm's law
electric potential
PE per unit charge
measured in volts
33
what is current in Ohm's law
how much charge flowing past a point in circuit in 1 sec
Q/T
Q=charge
T=time
Measured in coulombs/sec or amperes
34
what is resistance in Ohm's law
how much charge flow impeded
measured in ohm (Ω)
35
Coulomb's law equation
force= +number repels
force= -number attract
36
what other physiologic equation is based on Ohm's law
BP=COxSVR
37
YAG laser
shorter wavelength
greater ability to penetrate and destroy tissues
38
CO2 laser
longer wavelength
do not penetrate as deep into tissue and are more suitable for superficial lesions or airway surgeries
39
laser energy is in the form of
light
40
how is laser different from visible light (3)
monochromatic (one wavelength)
coherent (oscillate in the same phase and all protons move together)
collimated (narrow, parallel beam)
41
how to minimize o2 availability to prevent an OR fire
use minimum fio2 necessary
avoid nitrous oxide
42
how to manage fuels to prevent an OR fire (6)
use a laser resistant ET tube
protective wrapping of the ET tube
use a smaller diameter ET tube
add methylene blue and saline to ET cuff
make fuel objects wet with saline
use water based skin prep
43
what is electric potential
measures the potential push or force that drives electric charges through a circuit.
44
electric potential units
volts
45
example of electric potential in practice
EKG
46
define power
the rate at which energy is transported through an electrical circuit
47
power units
watts
48
atoms are continuously energized by photons when their electrons are already in a higher electron orbit. The outcome is the production of photons that that are of the same frequency and direction
stimulated emission--how lasers work
49
how do lasers work
they use a continual energizing of atoms in order to force photons that are of the same frequency and direction to be released which results in continuous production of monochromatic and unidirectional photons which can be directed into a laser beam.
50
what organs are most susceptible to thermal damage caused by lasers
eyes- retinal damage-> vision impairment, blindness
skin- thermal burns and tissue damage
51
how to prevent eye trauma from lasers
goggles
saline-covered gauze pads
tape eyes
52
how is radiotherapy effective in killing or reducing cancer cells
damages the cancer cells DNA, RNA and proteins that regulate vital cellular processes
53
2 risks of radiotherapy
production of new cancer cells
VTE
54
why is desflurane heated and pressurized?
Des has a high vapor pressure (660) and low boiling point
Must be pressurized to keep from boiling which would result in fatal doses administered to patients.
As molecules enter the vapor phase from liquid, they take heat with them, leaving the liquid with less heat energy than before. This would halt all transformation from liquid to gas which would result in administering little to no anesthetic gas to the patient.
55
Boyle's law and equation
the pressure inside the bottle increases when the size of the container decreases at the same rate for any gas
P1xV1=P2xV2
56
Charles law
as temp increases, volume increases
particles move away from each other
57
Avogadro's law
as number of gas particles added to a container is increased, the volume will also increase
58
Dalton's law
partial pressure law
59
mole fraction
ratio of the moles of a substance in relation to total moles present
60
Pa (partial pressure)=
Xa*Pt
Xa=mole fraction
Pt=total pressure
61
Henry's law
p=kc
p=pressure
k=constant
c=concentration
62
define vapor pressure
pressure exerted by a vapor on the walls of its container when in thermodynamic equilibrium, innate to every chemical
63
what would happen if you put sevo in an iso vaporizer
iso more readily enter vapor form than sevo, would underdose the patient
64
sevo vapor pressure
137
65
iso vapor pressure
238
66
what would happen if you put iso in a sevo vaporizer
iso more readily enter vapor form than sevo, would overdose the patient
67
des vapor pressure
660
68
what is des pressurized at
2atm
69
define second gas effect
coadministration of N2O and volatile anesthetic
N2O moves into blood faster than components of RA
as N2O diffuses from alveoli to the blood, the pressure within the alveoli drops, leaving a larger pressure gradient between vaporizer and alveoli, allowing larger influx of volatile anesthetic faster
70
define concentration effect
N2O leaving the alveoli results in increased percentage of volatile anesthetic
71
Gay-Lussac's law
P1/T1=P2/T2
at constant volume the pressure of a gas varies directly with the absolute temperature
72
Fick's law of diffusion
73
is N2O a liquid or gas at room temp
liquid
74
how much is in an ecylinder of o2
660L
2200 PSI
75
if you have an o2 cylinder with a psi of 1100 and you are running the o2 @3LPM, how long will it last
110min
76
how much is in an ecylinder of N2O
750psi
1600L
77
what is the minimum number of liters of N2O to have a 750psi
250
78
how much N2O do you have in a 12kg tank with an 8.8kg tare weight and a molecular weight of 44g/mol
[(12,000g-8,800g)/44g/mol]* 22.7L/mol=1650L
79
define enthalpy
heat content
joules
80
heat of fusion and vaporization
heat being used to break bonds to bring molecules to a higher energy state
81
what does MAC stand for
minimum alveolar concentration
82
MAC of sevo
1.8%
83
MAC of des
6%
84
high EMG frequency results in ____ energy
high
85
Beer-Lambert's Law
1. luminance of perpendicular light on a surface is proportional to the inverse square of the distance it travels from its source
2. the luminance intensity of angled light is proportional to the cosine of the angle with the normal
3. luminance intensity decreases exponentially as the light travels through a medium
86
with pulse ox wavelength is absorbed more by oxygenated Hg
940
87
with pulse ox wavelength is absorbed more by deoxygenated Hg
660
88
disadvantages of pulse oximetry (6)
susceptible to artifact and light
limits with hypothermic or vasoconstricted states
nail polish/acrylics
dye interference (ICG and methylene blue)
abnormal hgb states and erroneous values
risk of burns in poor perfusion states
89
DC circuit
direct current, flow of electrons in one direction
90
AC circuit
alternating circuit, flow of electrons reverses direction @ set freq (60Hz)
91
what is the max leakage current allowed in OR equipment
10µA
92
real life example of Beer's law
pulse oximetry
93
4 time invariant contributors
tissue thickness
skin hue
light intensity
venous blood
94
2 time variant contributors
arterial vol
o2 sat of hgb
95
Beer's law equation
A=abc
A= absorbance
a= constant of proportionality
b= path length
c= concentration of the analyte of interest
96
define roentgen
unit of radiation exposure in air
97
define rad
energy absorbed per gram of tissue
98
define rem
biological effect of a rad
99
who is more sensitive to radiation
children
10x
100
what affects exposure
"fatter the more scatter"
larger body parts lead to increased exposure
101
what types of cells are most sensitive to radiation exposure (4)
rapidly diving cells
sperm
lymphocytes
sm. intestine
stomach
102
where are radiation-caused tumors commonly located
bone marrow
gonads
lymphatic tissue
103
first signs of radiation damage
drop in WBC
skin burn
104
early effects of radiation damage (5)
death
hematologic depression
chromosome aberration
skin erythema
epilation
105
what is the whole body annual radiation dose limit
5000mrem/yr
106
what does compressing a gas quickly do to the kinetic energy
increases it resulting in a higher temperature
107
what should an ET cuff be inflated to
15-25mmHg
108
adiabatic change
when a gas is compressed or expands without a transfer of heat between the gas and its surroundings
109
bernoulli principle
low velocity and high pressure at wider diameter of tube
high velocity and low pressure at bottleneck
110
coanda effect
tendency of a fluid to cling to the wall of a tube or curved surface
111
critical temperature
temperature above which a substance can no longer be liquefied by the application of pressure alone
112
above a critical temperature a substance is known as a
gas
113
below the critical temperature a substance is known as a
vapor
114
what is it called when the rate of evaporation is equal to the rate of condensation
vapor is saturated
115
what can be detected by infrared absorption analysis
polyatomic molecules only
116
what cannot be detected by infrared absorption analysis
O2 and N2
