Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FRCA > Physics Viva > Flashcards

Physics Viva Flashcards

1
Q

Name the base units

A 
Length metre
time second
temperature kelvin 
mass kilogram 
amount mole 
luminosity candela 
Current amper
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Derived but not named units

A 
Area m2
Volume m3
Density Kg/m3
velocity m/s
acceleration m/s2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Named derived units

A 
Newton - force 
Pascal - pressure 
Joule - energy
Watt - power 
Coulomb - charge
Volt - potential
Farad - capacitance 
Ohm - resistance 
Weber - magnetic flux 
Tesla - flux density 
Henry - inductance 
Celsius - temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Boyles law

A

P ~ 1/V

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Critical temperature of oxygen and N2O

A

Oxygen -119 degrees

N2O 36.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an “ideal gas”

A

A gas that where individual molecules behave as individual particles that move in random manner independent of each other and other intermolecular forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Charles law

A

V ~ T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Gay-Lussacs law

A

P ~ T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ideal gas law

A

PV= nRT

n = number of moles 
R = universal gas constant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is avogadro’s hypothesis

A

Equal volumes of gases at a given temperature and pressure contain the same number of molecules

One mole of gas at STP will occupy 22.4 litres and contain 6.02 x 10”22 molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do we calculate N2O and O2 volumes that are in cylinders

A

N2O
- Use avogadros number and the weight of N2O and molecular weight of N2O

O2
- P1V1 = P2V2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Daltons law

A

The total pressure exerted by a gaseous mixture is equal to the SUM of each individual gas partial pressures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is oxygen manurfactured

A

Fractional distilation of liquified air (commercial)

Oxygen concentrators - zeolite absorbers absorb nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Poynting effect

A

The liquidation and separation of gas components when below the pseudocritical temperature

eg entonox less than -5.5 degrees

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Oxygen cylinder features

A

State: Gas
Colour: black/white
Cylinder pressure: 137 bar
Critical temperature: -119

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

N2O cylinder features

A

State: vapour
Colour: blue
Cylinder pressure: 52 bar
Critical temperature: 36.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Air cylinder features

A

State: gas
Colour: black/black-white
Cylinder pressure: 137 bar
Critical temperature: -141

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

CO2 cylinder features

A

State: vapour
Colour: grey
Cylinder pressure: 50 bar
Critical temperature: 31

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Entonox cylinder features

A

State: gas mix
Colour: blue/blue-white
Cylinder pressure: 137
Critical temperature: -5.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Heliox cylinder features

A

State: gas
Colour: brown/brown-white
Cylinder pressure: 137
Critical temperature: x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

O2 supply hospital

A

VIE

Cylinder manifold (size J)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define force

A

A vector quantity that can cause an object with mass to accelerate

1 newton will accelerate 1 kg at 1m/s2 in a vaccum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Units of pressure

A 
1 bar 
1 atmosphere
14.5 lb/in (psi)
30 inches of Hg
101 kPa
760 mmHg (Tor)
1020 cmH2O
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a gauge pressure

A

A pressure above or below atmospheric pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is absolute pressure

A

Pressure measurement incorporating atmospheric pressure `

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Different types of pressure regulators

A

Direct
Indirect
Two stage
Slave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Hagen-Poiseuille equation

A

Flow = Pi x Pressure change x radius”4 / 8 x L x Viscosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Laminar flow

A 
steady flow 
no eddies or turbulence 
pressure gradient must exist 
flow is proportional to this difference 
flow rate greatest at centre 
Reynolds number <2000
Viscosity of fluid important
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Turbulent flow

A 
chaotic 
eddies and swirls 
fluid velocity varies across the tube 
Resistance is not constant 
density of fluid is important

Flow is proportional to square root of pressure and radius squared
flow is inversely proportional to square root of tube length and square root of fluid density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the reynolds number

A

a number that predicts the onset of turbulent flow

(velocity x density x tube diameter)/viscosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Example of clinical application of Reynolds number

A

HELIOX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Critical velocity

A

The velocity above which the flow of a fluid within a given tube is likely to change from laminar to turbulent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How can flow be measured

A

Wright respirometer

Pneumotachograph - constant orifice, variable pressure

Rotameter - constant pressure, variable orifice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Describe the Bernoulli, venturi and coanda effect

A

x

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is viscosity

A

the tendency of a fluid to resist flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is turbulent flow proportional to

A

radius”2

Square root of pressure

Inversely proportional to length and density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Tube vs orifice …

A

Tube = laminar flow

Orifice = tube where the diameter exceeds the length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Explain resistance

A

The opposition to flow of DIRECT CURRENT

Unit Ohm
V=IR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Explain reactance

A

The opposition to flow of ALTERNATING CURRENT caused by the inductance and capacitance in a circuit rather than by resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Explain impedance

A

The total resistance to flow in ALTERNATNG CURRENT from both resistance and reactance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Explain a capacitor

A

A device that can store charge

2 conducting plates separated by an insulator

Amount of stored charge depends on:

  • size of plates
  • separation gap
  • dielectric material

It blocks DC but passes AC

Capacitative reactance decreases with increase frequency - SO.. diathermy with high frequency 1.5MHz will be conducted but mains electricity at 50Hz will not be conducted

Charge = capacitance x voltage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Energy stored by a capacitor

A

E=1/2 x charge x voltage

Or

E=1/2 x capacitance x voltage”2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Unit of capacitance

A

Farad

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Explain an inductor

A

A device that resists a change in electric current

A wire coiled around a ferrous core - when current passes a electromagnetic field is generated

This blocks AC but allows DC

Used in transformers and to isolate equipment from earth (floating circuits) and in defibrillators to smooth and lengthen current pulse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Explain a transformer

A

A device that transfers electrical energy from one circuit to another

Used to step up or down the voltages of alternative current in electrical applications

Essentially they are two inductors placed close to one another so the EM field in one generates a current in the other

Voltage generated in the second circuit calcultaed from FARADAYS law of induction `

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Diode or rectifier

A

Allows current to flow in one direction only

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What is a battery

A

A collection of galvanic cells that convert stored chemical energy to electrical energy

Two half cells (positive and negative) and conducting electrolyte

Oxidation occurs at the anode and reduction at the cathode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Amplifier

A

Makes the input signal larger for easier interpretation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Types of electrical filter

A

Common mode rejection

Amplifying only set frequency ranges

50
Q

Draw the defibrillator

A

Eurgh..

51
Q

Explain the defibrillator

A

Delivers DC shock
Uses 5000 volts - required step up transformer
Charges CAPACITOR (which have low reactance to AC and high resistance for DC)
When shock delivered runs through an INDUCTOR to prolong duration of current discharge

-> DC shock from 30A for 3ms with 5000V
thoracic impedance ~ 50-150 ohms

External monophasic defib - 360J
External biphasic defib - 150J
ICD - 20-50J

52
Q

Difference between DC cardioversion and defibrilation

A

Cardioversion synchronised to prevent R on T phenomenon which can cause VF

53
Q

What are the risks with defibrillation

A 
Burns 
Igniting flammable materials 
Interference with electrical components (ICD/pacemaker) 
Precipitation of VF
Electrocution of staff
54
Q

How do we minimise risks of defibrillation

A 
Training 
"stand clear" 
Checking device 
Audible alarm - "charging" "ready to shock" 
Dry patient surroundings 
Removing oxygen
55
Q

Describe mains electricity

A

AC current 50Hz at 240V

AC used to allow it to be transmitted over large distances with limited power loss

56
Q

UK mains electric wires

A

brown - live
blue - neutral
yellow/green - earth

57
Q

Explain the earth wire

A

Safety feature - connected to any exposed conducting parts of electrical appliance

If live wire came into contact with this part current would flow down earth wire and not into person touching

BUT BUT BUT

When using diathermy patients must be PROTECTED FROM EARTH WIRE - an earth wire would provide an alternative route for the diathermy current to flow potentially causing severe burns

58
Q

What do the adverse effects of electrocution depend on

A 
Current type (AC worse than DC)
Magnitude of current (V=IR)
Current density (current/area)
Current duration (greater duration = greater heat)
Tissues through which it flows (heart vulnerable to VF)
59
Q

Effects of different current amplitude

A 
0-5 mA = tingling
5-10 mA = pain
10-50 mA = Muscle spasm ("cant let go") 
50-100 mA = Respiratory muscle spasm & VF
5A - tonic contraction of myocardium
60
Q

Macro vs micro shock

A

macro - through whole body mains -> earth
- dangerous at mA level

Micro - direct to myocardium
- dangerous at microA level

61
Q

How is electrical equipment classified

A

Class I - earthed casing
Class II - double insulated casing (doesn’t need to be earthed)
Class III - battery operated

Type B - class I, II, III - low leakage current. Safe for connection to patient but not heart

Type BF - similar to B but patient is isolated via a floating circuit.

Type CF - considered safe for direct connection to the heart because the leakage of current is very small (less than 10 microA) - used for thermodilution catheters, ECG leads and pressure transducers)

62
Q

Measures in theatre to prevent electrical injury

A 
Anti-static floors 
Relative humidity of 50% (inhibits build up of static) 
Circuit breakers 
non-sparking switches and plugs
Regular checks and maintenance
63
Q

Classify solid materials according to their electrical conductivity

A

Conductors

Insulators

Semi-conductors

64
Q

Types of magnet

A

Permeant and electromagnets

65
Q

Features of magnets

A

All have north and south pole

Magnetic flux is the flow of energy from north to south pole (Webers)

Magnetic flux density is the amount of magnetic flux per unit area (tesla)

Strong magnets used in MRI are 1.5 tesla

66
Q

One ampere

A

One unit of charge (coloumb) per second

67
Q

What are the causes of electrical injury

A

Resistive coupling (faulty equipment and leakage) and capacitive coupling (person acts as one side of capacitor)

68
Q

Features of diathermy

A

AC current with high frequency - uses heating effect of passing current through tissue with high impedance to burn or vaporise tissues

heating effect depends on current density and duration

"Cutting" = alternating sine wave pattern 
"coagulation" = pulsed sine wave pattern

monopolar - single probe and diathermy plate. Power 100-400W

Bipolar - double probe so local electrical field. Power 40W

69
Q

Hazards of diathermy

A

Burns
Shocks
Pacemaker interference
Monitor interference

70
Q

What is heat capacity

A

The energy required to increase the temperature of a material by 1 degree

Specific HC = 1 kg
Molar HC = mole

71
Q

What is boiling

A

The point at which the SVP equals the surrounding ambient pressure

72
Q

Raoults law

A

The depression of SVP of a solvent is proportional to the molar concentration of the solute present

73
Q

What is temperature

A

Refers to the thermal state of a substance - it is the degree of “hotness” and reflects its potential for heat transfer

74
Q

How is temperature measured

A

Non-electrical, electrical and infra-red

NON-ELECTICAL

  • Liquid expansion thermometers (mercury/alcohol)
  • Gas expansion thermometers (bourdon gauge dial)
  • Bimetallic strip dial thermometer
  • Chemical thermometer
    - strip of small cells containing a mixture that melts over a range of temperatures to produce temperature dependent colour change

ELECTRICAL

  • Thermocouple - Two metallic strips, constant temp strip, galvanometer
  • Resistance thermometers - strip of metal, resistance proportional to temp
  • Thermistor - uses semi-conductor, resistance inversely proportional to temp

INFRA-RED
- All objects emit IR radiation depending on their temperature
- tympanic temp use tympanic membrane as reference of core temp
Use pyroelectric or thermopile sensors

75
Q

pyroelectric sensor

A

contain crystals that change polarity in given temperature

76
Q

thermoile sensors

A

numerous thermocouples connected in series and allows continuous measurement to be taken

77
Q

Classify types of scavenging

A

Active and passive

Passive - requires no external power , gas movement to the exterior is due to the pressure generated by the patient during expiration. Ventile system

Active - utilises an external power source such as a vacuum pump to generate negative pressure which propels gas into external atmosphere

78
Q

Problems with passive and active scavenging

A

Passive

  • excess positive or subatmospheric pressures at outlet can be caused by wind or air movement at the outlet
  • outlets at roof height - dense molcules can fall down

Active

  • excess positive pressure can lead to barotrauma
  • excess negative pressure can deflate reservoir bag of the breathing system and lead to re-breathing
79
Q

Methods of measuring oxygen concentration

A

Clark electrode
Galvanic fuel cell
Paramagnetic O2 analyser
Mass spectrometer

Photoacoustic spectroscope
Raman spectroscope
Chemical (Haldane apparatus)

80
Q

Describe the Clark electrode

A

Measures PO2 in solution

Main features

  • Platinum cathode
  • Silver anode
  • KCl solution
  • External power source
  • Blood sample with thin teflon membrane

2 equations
4Ag + 4KCl -> 4AgCl + 4K+ + 4e-
4e- + O2 + H2O -> 4OH-

Electrons go from silver to platinum

The cathode uses the electrons - the amount of which is proportional to amount of O2 so the current is dependent on amount of oxygen

Temperature dependent

81
Q

Describe the fuel cell

A

Measures PO2 in GAS mixture. Similar to the Clarke electrode

Main features:

  • lead anode
  • gold cathode
  • KOH solution
  • NO external power source
  • thermistor

Electrons are produced at the lead anode:
Pb + KOH -> PbO + H2O + e-

These electrons react with oxygen from gas sample with gold cathode acting as catalyst
O2 + 4e- + 2H2O -> 4OH-
Again electrons produced proportional to amount of avaliable oxygen and therefore current proportional

OH- ions return to anode and continue reaction
The thermistor is incorporate to allow temperature compensation

Lifespan dependent on lead anode
Slow response time

82
Q

Paramagnetic analyser

A

Oxygen and nitric oxide are both paramagnetic - they have unpaired electrons on outer ring

83
Q

Rate of diffusion of a gas dependent upon

A

Concentration gradient
Temperature
Molecular weight

84
Q

Rate of diffusion across a membrane

A

Membrane surface area and thickness

85
Q

Factors effecting the solubility of a gas in liquid

A

Temperature
Partial pressure
Chemical nature - ie polarity

86
Q

What is a vaporuiser

A

A device that allows accurate mixing of FGF and volatile anaesthetic agent

Classified:

in circuit - draw over, rely on subatmospheric pressure

Out of circuit - rely on PPV from a FG supply eg plenum

87
Q

Safety features of a vapouriser

A

Wicks - increase SA
Baffles - direct FGF onto surface of anaesthetic
Heat reservoir - heat conductive metal
Temperature compensation - bimetalic strip/med rod

Other

  • High internal resistance - prevents back flow
  • Maximum filling mark
  • Long high resistance outlet path
  • Anti-spill mechanism
  • Selectatec system (interlock bar system)
  • geometric/colour specific devices
88
Q

Cylinder sizes

A 
C 170l 
CD 460l Most small sued 
D 340l 
E 680l anaesthetic 
F 1360l Ambulance 
G 3400l 
J 6800l cylinder manifold
89
Q

Formula for energy

A

Energy (work) = force x distance

Or

Work = pressure x volume

90
Q

What is power

A

Power is the rate of energy use

WATT (joules/second)

(or work per time unit)

91
Q

MAP formula

A

DBP + 1/3(SBP-DBP)

92
Q

Non invasive BP measurement

A

Intermittent manual

  • sphygamometer
  • oilometer
  • Von reckinhouse ossilometer

Intermittent automatic
- DINAMAP

Continuous
- Penaz/finaprez

93
Q

How can CO2 be measured

A

Capnography

Severinghaus electrode

94
Q

Describe how CO2 is measured by infrared spectroscopy

A

CO2 absorbs infrared light

  • Absorbed by any molecule containing 2 or more types of atom
  • Different molecules absorb different wavelengths
  • By seeing how much of the wavelength is absorbed we can work out how much CO2 is present

Components:

  • Hot wire emitting IR radiation
  • Passes through a filter that only allows a certain wavelength through
  • Passes through chamber made of sapphire
  • reflected onto photo detector
  • parallel there is photodector

As stated by the Beer-Lambert law its absorption is proportional to the amount present and distance

95
Q

Types of suction

A

Active and passive

96
Q

Types of scavenging

A

Active and passive

97
Q

What methods are there to measure fresh gas flow

A

Most commonly a ROTAMETER

(CONSTANT pressure and VARIABLE orifice)

Made of bobbin, tapered transparent tube and needle valve

Flow of gas pushes up bobbin along tube with associated scale

  • Initial flow is laminar
  • becomes more turbulent as gap widens

So initially flow inversely proportional to viscosity and once turbulent flow predominates proportional to density

Mini-wright flow meter

Pneumotachograph

98
Q

Measurement of gas volumes

A

Commonly measured by measuring flow and multiplying by time

Other clinical scenarios:

  • Benedict Roth spirometer
  • Vitalograph
99
Q

What is an EEG

A

An electroencephalogram

Electrodes at the skin measure the electrical potentials from brain electrical activity

100
Q

Indications for EEG

A

Diagnostic: Seizures, encephalitis

Neuro-prognostication

Depth of anaesthesia monitoring

101
Q

Tell me about the EEG waveform

A

Complex waveform generated by pyrimidal cells in cortical layers 3 & 4

EEG uses 16 scalp electrodes with the resulting electrical signal having very low amplitude
- 10-50 microvolts

To reduce noise:

  • differential amplifiers used
  • high and low pass filters
102
Q

EEG waveform classifications

A

Beta - 13-35 Hz
Alpha 8-13 Hz
Theta 4-8 Hz
Delta 0-4 Hz

103
Q

How is EEG used to monitor anaesthesia

A

Used in depth of anaesthesia monitoring:

  • Delta and theta waves likely to represent surgical anaesthesia
  • Beta waves likely to represent awake patient
  • Burst suppression likely to represent unnecessary depth

Processed EEG used as 16-electrode EEG impractical. A 4 electrode frontal EEG creates a dimensionless index of depth of anaesthesia from 0-100

104
Q

Compare ECG. EEG and EMG monitoring

A

Electrode - Origin - amplitude - frequency

ECG - cardiac myocyte - 1-5 mV - 0.05-20 Hz

EEG - pyrimidal cells - 10-50 microV - 0.1 -30 Hz

EMG skeletal muscle - 0.1-1 mV - 40-3000 Hz

105
Q

Other than EEG monitoring, how can depth of anaesthesia be monitored

A
  1. Clinical signs
  2. Motor response to stimulation
  3. Population parameters (MAC)
  4. Rogue ones..
    - Skin conductance - sweat gland activity
    - Frontalis EMG - decreased activity means deeper
    - Isolated arm technique - tourniquets..
    - Lower oesophageal contractility - smooth muscle
    - Evoked potentials
106
Q

What is electric charge

A

The physical property of matter that causes it to experience a force when placed in an EM field

Charge = current x time

Couloumb (SI unit)

1 C = quantity of charge which passes a point when a current of 1 Ampere flows for 1 second

107
Q

What is capacitance

A

A measure of the ability of an object to hold charge

SI unit = farad

1 farad = potential difference of 1 volt is applied across a capacitors plates when they hold a charge of 1 coulomb

Q = V x C

108
Q

Properties of a capacitor that affect its ability to store charge and equation for energy stored

A

Distance between plates
Surface area of plates
Properties of insultator used

Energy = 1/2 x Q x V
= 1/2 x charge x voltage

109
Q

Components of defibrilator

A

Charging circuit and discharging circuit

110
Q

Differences between monophasic and biphasic defib.

A

Monophasic - only one direction with single discharge from capacitor

Biphasic - current flows forwards and backwards from two consecutive pulses of current. More successful at lower energy

111
Q

Transthoracic impedance

A

The impedance present by the patient during cardioversion
- lower impedance = greater charge reaches the heart

Factors that effect TTI:

  • paddle size
  • electrode coupling with skin (use of gel pads)
  • Paddle position
112
Q

Areas of the CNS effected by general anaesthesia

A

Cerebral cortex
Thalamus
Pontine reticular activating formation
spinal cord

113
Q

Methods of scavenging

A 
"removal of waste anaesthetic gases"
Active
Passive 
Cardiff Aldasorber 
 - Canister with activated charcoal connected to APL valve via tubing
114
Q

Cardiff aldasorber adv vs disadv

A

adv

  • small, portable
  • no set up cost

Dis

  • doesnt absorb N2O
  • have to weight the charcoal to see if used up
  • requires replacing every 12 hours
  • heating canister releases volatiles again
115
Q

Volatile max concentrations

A

N2O 100 PPM
Volatiles 50 PPM
Halothane 10 PPM

Averaged 8 hour concentration

Note other countries have different levels

116
Q

What are the different types of ventilators

A

Can be classified by:
- PPV vs NPV

PPV can be subclassified:

  • Volume cycled
  • Time cycled
  • Pressure cycled

Can also be classified by MoA

  • minute volume dividers
  • bag squeezers
  • Intermittent blowers
117
Q

HFOV

A

Pendulft principle

118
Q

HFOV

A

Pendulft principle

119
Q

Ideal portable ventilator

A 
Light 
easy to move 
Resistant to damage 
Adequate gas supply & low gas consumption 
Adequate battery 
Easy to use

Multiple ventilatory mechanisms
Adult and children

Oxylog 3000
Hamilton T1

120
Q

Laser types

A

Nd YAG

  • crystal used as lasing medium
  • 1064 nm (near infrared)
  • endoscopic surgery - cutting

Argon

  • gas lasing medium
  • 400-700 nm (near blue)
  • good penetration through clear tissues
  • used in eye surgery and derm (birthmarks)

CO2

  • gas lasing medium
  • 10.6 micrometer (infrared region)
  • highest power laser avaliable
  • poor penetration
  • superficial use
121
Q

How are lasers classified

A

Class 1 - power doesnt exceed maximum permissible exposure for eye

Class 2 - power up to 1mW and visible laser beam only. Eye protected by blink reflex

Class 3a - up to 5mW, visible spectrum only but laser beam must be expanded, eyes protected by blink

Class 3b - power up to 0.5w and any wavelength. hazardous so eye protection worn

Class 4 - power >0.5w and any wavelength. hazardous and capable of igniting flammable materials. eye protection essential

FRCA (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions