Physics equations Flashcards
1
Q
What SI Units do you know?
A
SMMACK
Second
Mole
Meter
Ampere
Candela
Kelvin
2
Q
What is second?
A
based on frequency of radiation emitted from Caesium 133
3
Q
What is mole?
A
same number of elementary particles as there are carbon atoms in 12g carbon 12. This is Avogadro number 6.023 x 10 23
4
Q
Ampere
A
the current that produces a force of 2x10 -7 Newtons per meter between two parallel wires
Is the amount of current that flows through a point in 1 second
5
Q
What is meter?
A
distance travelled by light in a vacuum in 1/300 000 000 seconds
6
Q
What is candela?
A
luminous intensity of a source that emits monochromatic radiation with certain frequency and intensity
7
Q
Kelvin
A
1/273.16 of triple point of water
8
Q
What derived units of mechanics do you know?
A
Force, Preassure, Energy
9
Q
What is Force?
A
That changes body state of rest or motion
The unit of force is Newton.
1 Newton is amount of force needed to accelerate mass of 1kg at rate of 1 m/s2
1 Newton is mass x acceleration
1 N = kg x m/ s2
10
Q
What is pressure?
A
Preassure is Force per unit area.
1 PA = Forca x area (N/m2)
One Newton of Force acting over 1 meter
11
Q
Energy
A
1 Joule= Force x distance (n.m)
One Joule of work is done when a force of one Newton moves a mass in one meter in the direction of the force.
12
Q
What are derived units of electricity?
A
PVC
Power
Voltage
Capacitance
Charge
13
Q
What is Power?
A
The rate of doing work.
Watt is unit of power.
Power = energy per unit time.
W=J/s
14
Q
What is charge?
A
The amount of current flowing in a given point per unit time.
It is Columb - A/s
15
Q
What is voltage?
A
Voltage is the potential differrence between two points of conducting wire when 1 Joule of work is done to move 1 Columb of charge between them
V=W/A
16
Q
What is FaraD?
A
Farad is unit of capacitance
F=C/V
17
Q
What units of pressure do you know?
A
10.2 cm2 = 1kPa
mmHg 750 mmHg is 100 kPa
100 kPA = 1 bar
1 atmosphere is 101 kPA
Dyn/cm2 1kPA = 10 000 cm 2
18
Q
What is Hertz?
A
Hertz is derived unit of frequency.
1 Hz is one cycle per second.
19
Q
What is kinetic energy?
A
The energy that body possesses because of its motion.
It is defined as the energy needed to to accelerate and object from a state of rest to its given velocity. This energy is equal to the work it would do when decelerating to return to the rest.
20
Q
What is potential energy?
A
The energy of the body or a system as a result of its position in an electric, magnetic or gravitational field. It is potential of the body to do work.
21
Q
What is momentum?
A
Mass x velocity
22
Q
What is Watt
A
1Joule per second
23
Q
What is Ohm?
A
Derived SI unit of Resistance
1 Ohm is the resistance between two points of a conductor when a constant potential difference of One Volt applied between them produces current of 1 Ampere
24
Q
what is pH
A
- log (H)
25
critical pressure
Critical pressure is the minimum pressure required to liquefy a substance at its critical temperature
26
STP
STP has been defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 100 kPa, 1 bar
27
What is boiling point?
The temperature at which the vapour pressure of a liquid = surrounding pressure and vapour turns
28
What is freezing point>
temperature at which liquid, solid are at equilibrium at given temperature
29
What is gas?
a substance above its critical temperature.
A gas will expand to fill any space available.
30
What is resistance?
The property of the current to oppose flow through it. The derived SI unit of electrical resistance is OHM.
31
What is SVP?
The pressure exerted by a vapour when in contact with an equilibrium with its liquid phase within a constant system at constant temperature.
32
Specific Heat Capacity
The amount of energy required to raise a temperature of 1 kg of a substance by 1C
33
Latent heat of vaporisation
the amount of heat required to convert a unit mass of a liquid at its boiling point without increase temperature
34
What is the unit of magnetic flux?
Webber Vxs
35
What is the unit of magnetic flux density?
Tesla Wb/m2
36
What is optimally damped system?
D=0.64
Maximises frequency response. Minimises overshoot of oscillations.
37
What is critical temperature for oxygen? Nitrous?
- 119 C
36.5 for Nitrous
38
What is Boyles law?
At constant temperature the absolute pressure of the gas is IRREVERSIBLY proportional to the volume (check the graph)
39
What is Charle's Law?
At constant pressure the volume is directly proportional to temperature
40
What is Gay-Lussac?
At a constant volume, the absolute pressure of a given mass of gas varies with temperature
41
PV=nRT . What is R?
8.32 J/K/mol
42
Hageen pouiselle
43
Reynolds
pvd/n (density/diameter/velocity)/viscosity
44
What is energy stored in Dif?
E=1/2CV(sq)
44
What is charge in defibrillator?
Charge= Capacitance (c) x Voltage
45
What is Doppler equation?
velocity = speed of sound wave x change in frequency/ 2x emitted frequency /cos (cosine angle in incidence)
46
What is 1 Tesla?
10 000 gauss
47
What is earth magnetic fields?
1 Gauss
48
How much are current MRI?
1 Tesla to 5 Teslas
49
Equation for Absorbance
A=elc
e- molar absorption coefficient
50
GOLD
1) 80
2) 50-80
3) 30 -50
4) 30
51
Major Haemorrhage Base Excess
1) 0 to -2
2) - 2 to -6
3) -6 to - 10
4) - 10 or more
52
Kidney Failure
1) 90
2)60-90
3)30-60
4)15-30
5)< 15
53
What is grade 2b
arytenoids are seen
54
grade 3
epiglottis
55
grade 4
no epiglottis visible
56
why Bain circuit is more efficient in controlled ventilation?
Because it controlled ventilation there is longer ventilatory pause
57
what is the approximate volume of the outer tubing?
around 500 ml
58
what would happen in the Bain circuit if there was a hole in reservoir bag
You would loose the ability to use control ventilation
In spontaneous ventilation you would loose the visual representation
59
What is Wilson score?
BMI
Neck moment
Jaw Movement
Reeceding mandible
Buck teeth
60
resonance
Resonance is the ability of an object to oscillate in response to a movement.
61
what is the resonance of the arterial system?
Arterial system is designed to have resonance above 40 Hz
62
Adverse features
SHOCK SYNCOPE MI HEART FAILURE
63
RISIS OF ASYSTOLE
MOBITZ TYPE II
COMPLETE HEART BLOCK
VENTRICULAR PAUSE > 3 sec
RECENT ASYSTOLE
64
4HT and 4T
HYPOXIA
HYPOVOLEMIA
HYPO/HYPERKALEMIA
HYPOTHERMIA
65
Malanmpatii
Class 1: Full visibility of tonsils, uvula and soft palate
Class 2: Visibility of hard and soft palate, upper portion of tonsils and uvula
Class 3: Soft and hard palate and base of the uvula are visible
Class 4: Only Hard Palate visible
66
Wilson score
Weight
Head and neck movement
Jaw moment
Receding mandible
Buck Teeth
67
relative humidityty
absolute humidity/satured amount of water = at given TEMPERATURE
68
methods of humidification for OCSE answers
HME filters
Nebs
Hot water bath humidifier
Soda Lime
69
What's the difference between bipolar and monopolar?
patient does not part form of the circuit
circuit is not earth
patient is part of the circuit, earth, isolating transformer
70
What happens if diathermy plate is dissipated and diathermy is activated?
- current would flow through the patient and any metal object attached to the patient through the path of less least resistance
- increased current density at the level of the burns
- not to be placed over hip prosthesis
71
What colours are diathermy
Yellow - CuTTing - Monopolar - cutting - smaller area, heating up water
Blue - Bipolar - coagulation - charring
Blended - combination of both
72
contradictions
refusal
allergy
infection
coagulopathy
73
How would you perform axially nerve block
positioning
probe
negative ASPIRATION
injection PREASSUREE
74
What causes rr state in pregnancy?
protein C and protein S
Increased clotting factor II, VII, IX, X
increased tPA-1
Venous stasis
Heterozygous carriers of factor V laden, anti-phospholipid syndrome
75
What are the components of oesophageal temperature probe?
Thermistor
Whetstone Bridge
Metal Oxide
76
What's the relation of Kelvin to Celsius
OK = - 273 C
1k has the same order of magniude as O C
77
What is tripple point of water?
0.01 C at 611.7 Pa
78
What are three phases of heat loss during anaesthesia?
(A) Redistribution of heat from the core to the periphery following induction of anesthesia; (B) Heat loss to the environment, (C) Steady state and rewarming
79
How long do you have to wait for prophylactic versus therapeutic dalteparin?
12h Prophylactic
24h Therapeutic
80
Pain during cesarean
T10 - somatic pain during c-section
T4 - to abolish visceral pain and discomfort
81
What are the safety features of the diathermy?
1) outer case is earthed
2) isolating capacitor: provides high impedance to low frequency current
3) floating circuit
82
What are limitations of galvanic cell?
1) Temperature compensation requires Thermistor
2) Has to be placed in Expiratory Limb
3) Not compa
83
two methods of measuring oxygen
paramagnetic
pulse field analyser
84
Stellate ganglion block technique
1) The patient is in a supine position with slight extension of the neck
2) transducer is placed on the neck at the level of C6 to enable cross sectional visualization of anatomical structures. At this level, the carotid artery, internal jugular vein, thyroid gland, trachea, longus colli muscle, root of C6, and transverse process of C6 are identified.
3) To retract the carotid artery laterally a
4) Using an in-plane approach, a 1.0-inch, 25-gauge long-bevel needle is inserted paratracheally toward the middle of the longus colli
5) The endpoint for injection is the ultrasound image demonstrating the tip of needle penetrating the prevertebral fascia in the longus colli.
85
Contradictions of stellate ganglion block
CONTRAINDICATIONS
Recent myocardial infarction
Anti-coagulated patients or those with coagulopathy
Glaucoma
Pre-existing contralateral phrenic nerve palsy ( may precipitate respiratory distress)
86
Block specific complications
pneumothorax
phrenic nerve
vagus nerve
carotid artery puncture
87
if post resus patient responds to fluid rescuitation what would you do?
- Gain more IV access
- Further Rapid IV infusion
- Send Bloods for cross-match
- Arrange for urgent laparotomy
88
What did you forgot in GA mask station?
pre-medication
pre-oxygenation not essential (depending on the type of the surgery)
89
what is doppler shift?
the difference between the frequency emitted and received
90
what parameters you can read from the Doppler?
Contractility: highest blood velocity
Preload: flow time (narrow trace suggest hypovolaemia)
Stroke volume: velocity/time
91
describe the Principle of bioimpedence
4 electrodes are positioned in the neck
4 in the mid axially line
the resistance to current from innermost to outermost is measured
A fat does not conduct electricity, bioimpedence is related to the water content of the thorax
Bioimpedence changes through cardia cycle
92
cricoid summary
T6 level
10N-40N
High risk surgery ; GI, obstetric, RSI
93
cricoid contradiction
Truma
Active vomiting
Unstable Cervical Spine Injuries
94
cell saver
>500 ml blood anticipated
Jehovas
Anemic
Rare blood groups
No risk of infection
Allogenic blood transfusion reaction
Better oxygen delivery
Contradiction:
Refusal
Malignancy
Haemoglinopathies? sickle cell
suction + swabs > heparinised in saline > filtered 200 micron > centrifuged > separation and washing process.
presented for reinfusion as a high haema- tocrit (approximately 60%) suspension of packed red cells in normal saline.1
DUAL LUMEN SUCTION LINE
lower suction pressures
Anticoagulant solutions are also added at the time of blood collection; this can be either heparin (5000 units L1) or a citrate-based preparation
mpared with stored allogeneic red cells, salvaged red cells retain their elliptical profiles and retain their deformability better and have increased concentrations of 2,3-diphosphoglycerate and ATP.4 As a result, tissue oxygen delivery is superior to that provided by donor red cells.
Complications: reunfusion hypotension (hypocalcemia snd bradykinin)
Fat embolus, tissue embolus
Contradictions:
trained staff
patient refusal
95
What are three stages of heat loss in anaesthesia?
1) Rapid Reduction in Core Temperature due to redistribution of the cold to the periphery
2) Decrease in BMR (uncoupling)
3) Coupling (plateu) but not in regional
96
Consequences of hypothermia
Shivering
Cardiac Morbidity
Pour wound healing
Delayed Emrgence
a) prolonged neuromuscular blocage
b) Increased plasma concentration of propofol and fentanyl
Cardiac: MI, cardiac morbidity , arrhythmia
Coagulation: reduced platelet function
Wound Healing - due to low oxygen tension and suppressed immunity
Drugs:
Muscle relaxants - prolonged
MAC - decreased (increased solubility in adipose)
Propofol anf fentanyl increased plasma concentration
97
sizing double lumen tubes
37F women
39 Men
98
Parkland formula
99
What is the Peltier effect?
Opposite the Seebeck effect - junction of two dissimilar metals is used to rapidly Cool down solution to measure OsmolaLity
100
OsmolaRITY
2NA + UREA+gluocose
101
What is normal osmolaRITY?
280-305
102
How osmolality is measured?
depression of the freezing point
sample cooled down slowly to O C then rapidly to -7 this is by using Peltier Effect )opposite the Seebeck effect.
A mechanical pulse triggers freezing
the latent heat of fusion warms the solution
103
What is osomolar gap?
Measured minus calculated
104
What are the causes of Osmolar Gap?
Alcohol, Methanol Ethylene glycol High Triglycerides
105
What is the anion gap?
Anion Gap = Na+ – (Cl- + HCO3-)
106
Capacitator capacitance
of 1Farad holds a charge of 1 Columb if 1 volt across plates F=C/V.
107
1 Columb is
a charge passing when 1 Amper flows through 1 sec C=Amps*sec
108
Inductor inductance
1 Henry
109
What is relationship between energy and work?
Work = force x distance= pressure x volume
Interchangeable measured in Newtons and Joules
110
Phases temperature loss
redistribution
linear
plateu
111
Massive transfusion
Defined by red blood cell transfusion of 50% of total blood volume (TBV) in 3 h, 100% in 24 h, or >10% of TBV per minute.
112
Battery Safety Low Voltage (III)
113
