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Teach me bank Flashcards

1
Q

how is volume of local anaesthetic in a obstetric spinal compare to normal?

A

REDUCED AMOUNT REQUIRED

Due to reduced CSF volume and the loss of the lumbar lordosis, there is a risk of a high spinal unless the volume of local anaesthetic is reduced.

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2
Q

what level of block is required for a C section?

A

block to T4-T5

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3
Q

what factors influence the efficiency of HME?

A

Performance is affected by:

  • Water vapour content of expired gas (the higher, the more efficient)

Inspiratory and expiratory flow rates (relate to time gas in contact with HMEF material).

Volume of HMEF material (larger = more efficient).

Thermal conductivity of HMEF material. Material with a low thermal conductivity maintains a greater temperature without loosing to environment.

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4
Q

what is Edrophonium?

A

short acting acetylcholinesterase inhibitor

can temporarily relieve myasthenia symptoms

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5
Q

what are the subunits in a nictotinic Ach receptor?

A

The nicotinic receptor has 5 subunits – two alpha, one beta, one delta and one epsilon.
The epsilon unit replaces the gamma unit that is found in the foetus.

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6
Q

when can acetazolamide be used?

A

altitude sickness
glaucoma
metabolic alkalosis

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7
Q

write the equation for wash in curve…

A

y = a(1-e-kt).

sometimes as
A - Be-kt = just multiplied out of brackets

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8
Q

what is the mechanism of action of milronone?

A

phosphodiesterase III inhibitor, and therefore increases the concentration of cyclic AMP. This leads to increased intracellular calcium, and therefore increased myocardial contractility

improves CO

(increased cAMP in vessels causes vasodilation - reduces afterload)

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9
Q

how does cAMP rise in smooth muscles result in vasodilation?

A

cAMP –> PKA –> phos of L type Ca channels –> reduced entry of Ca

also phosphorlyates pumps and proteins to increase efflux of Ca

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10
Q

how much suggamadex is given in different situations?

A

The dose required is determined according to the degree of neuromuscular blockade:

Immediate reversal following RSI – 16 mg/kg.

Deep block (1 – 2 twitches on post tetanic count) – 4 mg/kg.

Moderate block (2 twitches on ToF) – 2 mg/kg

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11
Q

how is MAC affected by pregnancy?

A

reduced

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12
Q

what type of tilt is recommended in preg to relieve aortovenal compression

A

left lateral

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13
Q

why can oxytocin only be given after delivery of term baby?

A

Giving 5 units of oxytocin as a bolus prior to delivery would cause a substantial increase in uterine tone despite the presence of the foetus, with catastrophic consequences.

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14
Q

how does propofol cause hypotension?

A

Propofol impairs central vasomotor control and has peripheral effects on inhibition of L-type calcium channels.

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15
Q

what is the cori cycle?

A

Excess lactate produced in the muscles is shuttled through the blood stream to the liver where it undergoes gluconeogenesis at the expense of 6 ATP.

glucose is shuttled back to muscles for glycolysis

can only occur in aerobic conditions

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16
Q

what is the order of highest to lowest MAC? i.e. least to most potent

A

Nitrous oxide – Xenon – Desflurane – Sevoflurane – Enflurane – Isoflurane – Halothane.

‘no X delicious Sex equals incredible happiness’

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17
Q

what is the bohr equation?

A

Vd / Vt = (PaCO2 – PeCO2)/PaCO2,

where Pa and Pe are the arterial and expired partial pressures of carbon dioxide

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18
Q

what does an undersized cuff do to BP readings?

A

overestimate
of systolic AND diastolic

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19
Q

which ant acid causes diarrhoea?

A

magnesium trisilicate

(Aluminium containing antacid medications also tend to cause constipation rather than diarrhoea)

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20
Q

which antiepileptics are Na channel blockers

A

Phenytoin, carbamazepine and lamotrigine.

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21
Q

what is the action of ethosuximide

A

Calcium current inhibitors

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22
Q

what contributes to phase 4 of cardiac pacemaker cells?

A

funny current sodium channels and T-type calcium channels

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23
Q

what is the max dose of ramipril?

A

10mg

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24
Q

what should BP in community be before elective surgery?

A

<160/100mmHg

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25
Q

what are the immediate, delayed and late complications of a tracheostomy?

A

Immediate – failure, haemorrhage, tube misplacement, occlusion of tube by herniated cuff, occlusion of tube by tracheal wall.

Delayed – blockage with clot or secretions, overinflation of cuff leading to mucosal ulceration.

Late – granuloma formation, persistent sinus, scar formation, tracheal dilatation.

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26
Q

what type of current is delivered by TOF?

A

50mA
2Hz - 1 stimulus every 0.5 seconds
4 in total
each lasts 0.2ms

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27
Q

how does a pressure / volume loop look for aortic stenosis?

A

thinner and narrower

same end systolic volume , reduced SV hence increase in EDV

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28
Q

which metabolite of morphine is active?

A

morphine 6 glucuronide

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29
Q

what structure passes through foramen spinosum?

A

middle meningeal artery

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30
Q

which structure passes through the foramen rotundum?

A

maxillary nerve

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31
Q

what structure passes through the optic canal?

A

opthalmic artery
optic nerve

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32
Q

which structure passes through the foramen ovale ?

A

mandibular nerve

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33
Q

which Abx caused most anaphylaxis according to NAP 6?

A

Teicoplanin and then co amox

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34
Q

what is the spaulding classification?

A

The Spaulding classification stratifies the risk of infection transmission based on the patient tissue the device will contact during use.

Critical items enter normally sterile field, or vascular system through which blood flows. There is a high risk of infection, and these items should be sterilised e.g. catheters, canulas

Semi-critical items touch mucus membranes or broken skin barriers. There is an intermediate risk of infection and these items require high level disinfection e.g. laryngoscopes.

Non-critical items only contact intact skin. There is a low risk of infection, and these items require low level disinfection e.g. blood pressure cuff, tympanic thermometer.

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35
Q

what is the absolute humidity of a room at atm presure at 20 degrees?

A

293 K is approximately 20 ºc, and at this temperature fully saturated air has an absolute humidity of 17 g/m³.

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36
Q

how do opioids exert action on receptor?

A

stimulation of Gi
hyperpolarisation
via K+ efflux

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37
Q

with spinal anaesthetic, which antiplatelets should be stopped and when?

A

aspirin = continue
clopidogrel and prasugrel = 7 days
Ticagrelor – 5 days.
Abciximab – 2 days.
Tirofiban – 8 hours.

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38
Q

which GI medication can increase warfarin effects?

A

cimetidine = H2 antagonist
used for reflux

inhibits CYP450

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39
Q

what are the recommended allowance for inhalation agent occupational exposure?

A

COSSH (control of substances hazardous to health) specifies that for people exposed to anaesthetic agents the maximum occupational exposure over an 8 hour period is….
100 ppm for nitrous oxide
50 ppm for enflurane and isoflurane
10 ppm for halothane.
sevoflurane of 20 ppm.

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40
Q

in a dose response curve, which axis is logarithmic?

A

x axis - log dose
y axis - response % of max response

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41
Q

how is relative risk calculated?

A

note not relative risk reduction.

relative risk = % in new drug / % incidence in old drug

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42
Q

what is the absolute pressure of a cylinder?

A

gauge + atm
e.g. 13700 + 101

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43
Q

what is the pka, PB and relative solubility of lidocaine, bupivacaine and prilocaine?

A

Lidocaine has pKa 7.9, protein binding 70% and relative lipid solubility 150.

Prilocaine has pKa 7.9, protein binding 55% and relative lipid solubility 50.

Bupivacaine has pKa 8.1, protein binding 95% and relative lipid solubility 1000.

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44
Q

for LA what determines speed of onset, potency and long lasting?

A

pka = speed
lipid solubility = potency
PB = lasting effects

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45
Q

what is the critical pressure of nitrous oxide?

A

72 bar

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46
Q

what is the volume of CSF in healthy adult?

A

150ml

Around 500ml produced per day

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47
Q

what is the urea cycle?

A

conversion of ammonia to urea
occurs in hepatocytes - between mitochondria and cytosol
urea can then be excreted

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48
Q

what dermatome and myotome is responsible for sensation of anterior thigh and hip flexion

A

L2
The L2 myotome is responsible for hip flexion and the L2 dermatome supplies the anterior aspect of the thigh.

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49
Q

how do B agonists and aminophylline interact?

A

synergistically

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50
Q

what is the root mean square deviation. ?

A

same as Standard deviation (different name)

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51
Q

what is a geometric and arithmetic mean?

A

The geometric mean (nth root of the product of values) is advantageous over the arithmetic mean (sum of values/number of values) in skewed distributions as it is affected to a lesser degree by extreme values

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52
Q

what is the Eustachian valve?

A

found at entrance of IVC to RA - directs blood towards foramen ovale and into LA rather than RV in fetus
i.e. reduces mixing of SVC deoxygenated blood and oxygenated blood from IVC

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53
Q

which diabetic medication is contraindicated in congestive HF. what else is this contraindicated in?

A

thiazolidinedione e.g. pioglitazone

contraindicated in patients with congestive heart failure, diabetic ketoacidosis and active bladder cancer.

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54
Q

what class of drug is tolbutamide

A

sulphonylurea

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55
Q

how much CSF is produced each day in health?

A

450 ml

(3x normal volume = normal vol is 150ml)

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56
Q

in cant intubate, cant oxygenate, what is recommended?

A

cricothyroidotomy
NOT Tracheostomy

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57
Q

when may a mainsteam analyser be used for gas analysis?

A

neonate - less deadspace, more accurate for smaller volumes

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58
Q

The innervation to the abdominal wall is provided by the anterior rami of spinal nerves. Between which layers of the abdominal wall do these nerve fibres travel?

A

transverse abdominis
internal oblique

this is where local acts in a TAP block

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59
Q

how does TEG work? (thromboelastography)

A

In TEG, 360 μL of whole blood is added to a cup.
A clot activator, kaolin, is then added.

rotated over a period of 10 seconds before the direction of rotation is reversed.

A torsion wire on a pin is lowered into the sample which detects frictional forces generated as a result of blood clotting.

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60
Q

what are the following parameters in TEG - R time, K time, a angle

A

The R time (reaction time) is the time taken between beginning an assay and point when the amplitude is 2mm. This represents the time for fibrin formation to begin.

The K time is the time from the R time to when the amplitude is 20mm wide. This is used as a measure of clot strengthening.

The α angle is the angle to the horizontal made by straight line between the R time and K time. This represents how quickly a clot forms.

The MA is the maximum amplitude of the graph and represents the maximum strength of clot.

CL30 (clot lysis 30) is the width of the graph 30 minutes after maximum amplitude. It represents fibrinolysis.

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61
Q

how is rivaroxaban immediately reversed?

A

andexanet alpha
OR
prothrombin complex concentrate (Beriplex, 50 units/kg)

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62
Q

in infrared spectroscopy, why is a crystal window used for which infrared light passes before sampling chamber?

A

crystal window is used because glass absorbs infrared radiation

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63
Q

in fetal circulation, which structure is important in ensuring oxygenated blood goes preferentially to the brain?

A

Eustachian valve

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64
Q

how many drops of fluid and blood is equivalent to a ml?

A

20 drops = 1 ml of fluid
15 drops = 1 ml of blood

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65
Q

describe components of a circle system..

A

patient expires
one directional valve
APL , reservoir and ventilator are all next
then soda lime
then FGF flow in
then inspiratory one way valve
then patient

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66
Q

what type of chemical are all 4 induction agents?

A

ketamine = phencyclidine
propofol = phenol
thiopentone = barbiturate
etomidate = imidazole (has an ester link)

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67
Q

what are the induction doses of the IV induction agents?

A

propofol = 1-3mg/kg
thio = 3-7mg/kg
ketamine = 1-2mg/kg
etomidate = 0.3mg/kg

hence etomidate 10x more potent

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68
Q

what are the pka values of induction agents?

A

propofol = 11
etomidate = 4
thio = 7.6
ketamine = 7.5

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69
Q

of the IV induction agents which has smallest Vd?

A

largest propofol = 4mg/lg
smallest thio = 2.5mg/kg

ket and etomidate = 3mg/kg

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70
Q

what are the design features of the ET tube that enhance safety?

A

left facing bevel - gives optimum view on intubation

murpheys eye - allows ventilation if tip is occluded

magil curve - makes the tube insertion easier to follow anatomy of upper airway

low pressure high vol cuff - reduces aspiration and tracheal damage

vocal cord guide - two black liens to indicate where cords should sit - prevents endobronchial intubation

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71
Q

what is the mechanism of tirafiban?

A

glycoprotein IIb / IIIa antagonist - antiplatelet
blocks platelet aggregation

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72
Q

give examples of ADP receptor blockers…

A

clopidogrel
prasugrel
ticagrelor

inhibit platelet activation

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73
Q

which antibiotics can worsen weakness in myasthenia gravis?

A

aminoglycocides - gentamicin, streptomycin

macrolides - clarithromycin, azithromycin etc

fluroquinolones - ciprofloxacin

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74
Q

which receptors do clonidine and dexmedetomidate bind?

A

both A2 agonsts

but clonidine also has A1 receptor activity and hence causes some HTN initially (paradoxical HTN)

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75
Q

what is the formula for cuff size of ET tube in children?

A

age / 4 + 4

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76
Q

what parts of spinothalamic tract carry what sensations?

A

lateral = temperature + pain
anterior = crude touch and pressure

(dorsal = light touch, vibreation , proprioception)

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77
Q

what is newtons 1st 2nd and 3rd law?

A

1st = inertia. in absence of all force, the object will remain at rest or constant velocity. (hence momentum also constant)

2nd law = accelaration is directly proportional to the net force acting on it and inversely proportional to mass (F=ma)

3rd law = for every action there is an equal and opposite force.

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78
Q

what is the catheter mount in a breathing circuit?

A

the part that connects to the tube and filter
prevents the moving and causing endotracheal intubation.

45-170mm tube with a proximal 2mm connector and distal 15mm / 22mm connector

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79
Q

what is the primary intracellular buffer?

A

phosphate

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80
Q

what is the urinary buffer?

A

phosphate
ammonium
bicarb

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81
Q

what are the cathodes and anodes of a galvanic fuel cell?

A

LAG = lead anode, gold cathode

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82
Q

what can Piezoelectric quartz crystal oscillation be used for?

A

volatile anaesthetic measurement

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83
Q

which vessels does GTN act on?

A

low dose - veins / capacitance vessels - decreased preload , compensatory tachycardia

high dose - arteriolar dilation - reduced afterload

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84
Q

what is damping coefficient for optimal damping?

A

0.64

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85
Q

whats the ratio of adrenaline/NA release by adrenals?

A

80:20
more adrenaline

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86
Q

what type of filter is used in anaesthesia/ intesive care for patients breathing system?

A

HME PLUS pleated hydrophobic filter (antimicrobial and more efficient than electrostatic)

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87
Q

what is reactance, impedance and resistance?

A

Resistance describes the opposition to flow of direct current.

Reactance is used when the current is alternating.

Impedance (Z) is the sum of resistive and reactive components.

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88
Q

what is the action of dopamine in CVS pharmacology?

A

at low dose = D1 and D2 agonist - increased renal blood flow

at larger doses = beta agonist = positive ionotropy

high doses = alpha adrenoreceptor - vasoconstriction

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89
Q

what is pralidoxime?

A

antidote for organophosphate poisoning

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90
Q

in pressure swin adsorption for concentrating oxygen what chemical is used to remove the nitrogen

A

Zeolite = aluminium and silica crystals

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91
Q

what does a wrights respirometer measure?

A

expiratory volumes

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92
Q

what size of particles are deposited where in the lungs?

A

upper airways - 20um
tracheobronchial tree = 2-5um
alveoli - 0.8 to 3um
below 1um - inhaled and exhaled

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93
Q

which dural sinus does the IJV originate from?

A

sigmoid sinus
exits via jugular foramen

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94
Q

what is protein binding of digoxin and amiodarone like?

A

high - one can displace the other leading to toxicity

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95
Q

why are children more prone to bradycardia in theatre?

A

increased parasympathetic tone
more affected by vagal stimulation

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96
Q

what is the mechanism of cangrelor? how is it given

A

reversible ADP inhibitor
given IV
rapid onset and quick recovery

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97
Q

what is the safe occupational exposure of halothane?

A

10ppm

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98
Q

what is the onset and duration like for prilocaine? what is the protein binding like? pKA?

A

rapid onset
medium duration
55% PB
Pka 7.7

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99
Q

what is the Vd of ketamine?

A

3L/kg

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100
Q

what is the half life of amiodarone?

A

long
up to 100days

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101
Q

what is the dose of amiodarone?

A

loading = 300mg over 1 hour
then = 900mg over 24 hrs

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102
Q

what is the typical value of pulmonary capillary wedge pressure?

A

6-12 mmHg

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103
Q

what are typically values of right atrial pressure, right venticle pressure, pulmonary artery pressure, wedge pressure??

A

right atrium = 0 to 5mmHg
right ventricle = 20-30/ 0-5mmHg
pulmoanry artery = 20-30/ 10-20mmHg
wedge = 6-12mmHg

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104
Q

what is reflux and siphoning in drug infusion pumps?

A

reflux = multiple drugs in a cannula, distal obstruction, the drugs will be reflux up the line

siphoning = drugs will flow freely without syringe driving them due to gravity effect.

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105
Q

how is pulmonary vasc resistance measured?

A

PVR = 80 x (Mean pulmonary artery pressure - LA pressure)/ CO

units dyne.s-1.cm-5

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106
Q

what do the positions on pacing indicate?

A

position 1 - chamber paced
position 2 - chamber sensed
position 3 - mode of response
position 4 - programmable functions
position 5 - anti tachy mode

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107
Q

what is the difference between a thermistor and thermocouple?

A

thermistor… The resistance typically decreases as temperature increases, however for certain semiconductors resistance increases with temperature.

thermocouple… seebeck efect …At the junction of two dissimilar metals, a voltage will be produced in proportion to the temperature difference between two such junctions.

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108
Q

what metals are typically used in a thermocouple?

A

copper and constantan
two dissimilar metals
seebeck

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109
Q

which anti HTN med on ITU is a red / brown powder? what is the toxcity effect of this?

A

sodium nitroprusside

produces nitric oxide, cyanide ions and methaemoglobin

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110
Q

what type of giving set should be used with sodium nitroprusside?

A

opaque
degrades in sunlight

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111
Q

what is a rare haematological side effect of gold?

A

pancytopenia

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112
Q

what is the order of toxicity based on location for local anaesthetic agents?

A

in order or descending incidence:

Intercostal space > caudal > epidural > brachial plexus > femoral > subcutaneous.

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113
Q

what are the different sizes for BP cuffs?

A

Appropriate sizes are:

3cm – infant.
6cm – child.
9cm – small adult.
12cm – adult.
15cm – large adult.

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114
Q

what do the following degrees of current do to a patient if accidently exposed
1mA, 5mA, 15mA, 30mA, 50mA, 100mA, 1000mA

A

1 = tingling
5 = pain
15 = severe pain and muscle contraction
30 = cant let go
50 = asphyxia (resp muscle contraction)
100 = VF
1000 = burning

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115
Q

what structures pass the superior orbital fissure?

A

lacrimal nerve
frontal nerve
trochlea nerve
occular motor nerve
abducens nerve
nasociliary nerve

opthalmic vein

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116
Q

how is rocuronium mainly excreted?

A

bile

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117
Q

what class of muscle relaxant is rocuronium?

A

monoquarternary aminosteroid

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118
Q

in a system how can natural resonance relate to different properties e.g. of arterial pressure system?

A

NF ∝ d/√(cρl) where d = diameter, c = compliance, l = length and ρ = density.

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119
Q

how does class Ia, b, c anti-arrhythmics effect refractory period?

A

1a = increase
1b = decrease
1c = no effect

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120
Q

what factors affect the likelihood of hard with current to the body?

A

most important factor = frequency.
unfortunately mains frequency of 50Hz is most damaging

amplitude of current
duration of current

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121
Q

what can hydralazine precipitate?

A

SLE

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122
Q

what can happen when sodium nitroprusside is stoped?

A

rebound HTN

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123
Q

what can you say about metabolism of hydralazine?

A

polymorphisms
variable clearance due to 50% being slow acetylators

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124
Q

how can you classify the Manley MP3?

A

pressure generated
time cycled
minute volume divider

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125
Q

how does a left sided double lumen ET tube work?

A

2 lumens - one clear and one blue
the blue lumen goes into left lung

if clear balloon inflated = both lungs ventilated

if blue balloon inflated and breathing system connected to clear tube = right lung inflated

if blue balloon inflated and breathing system connected to blue tube = left lung inflated

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126
Q

why is a transformer used in a debib circuit?

A

step up from 240V to 5000V

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127
Q

describe how Class I, II, III equiptment safety is categorised?

A

class I - earthing
class II - extra insulation, no earth
class III - extra low voltage

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128
Q

what is class B, BF and CF equiptment?

A

class B - externally placed equiptment on patient can be class I, II or III. max allowable leakage current 500uA

BF - similar to B but isolated circuit

CF - cardiac contact - max leakage 50uA

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129
Q

which antibiotic can give serotonin syndrome?

A

linezolid

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130
Q

what are the side effects of MAOI?

A

psychosis
weight gain
orthostatic hypotension

serotonin syndrome (if used with other serotonergic agents)
hypertensive crisis if certain tyramine rich foods are consumed.

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131
Q

what are the 5 methods of filtration by filters used in breathing systems?

A

Interception (1 μm)

Inertial impaction (0.5-1 μm)

Gravitational settling (> 5 μm) –

Brownian diffusion (< 0.5 μm) – random movement and hence collision

Electrostatic interaction –

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132
Q

how is a canula sterilised prior to use?

A

it is packaged so cant undergo autoclave

it is sterilised via ionising radiation

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133
Q

how is majority of atracurium metabolised?

A

60% ester hydrolysis
30% hoffman
10% unchanged

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134
Q

how does acidosis affect hoffman?

A

slowed by acidosis and cold

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135
Q

what common drug cant be given with clopidogrel and why?

A

omeprazole
inhibits CYP 2C19 - cant convert clopi to active form - less effect

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136
Q

which is the anti emetic of choice in parkinsons?

A

Domperidone

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137
Q

how much CO2 can be absorbed by 500g of soda lime?

A

125L

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138
Q

what factor doesnt affect the accuracy of pneumatograph

A

resistance of the device

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139
Q

what does the SAGM solution consist of and why?

A

Saline
adenine
glucose
mannitol

this solution is ideal to allow greater volume of plasma to be removed from blood in order to use FFP as a separate product

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140
Q

RBC can be stored in citrate -dextrose - what is this solution good for?

A

citrate binds calcium and acts as an anticoagulant
dextrose acts as a RBC substrate

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141
Q

how long can RBC survive with citrate phosphate dextrose vs citrate dextrose?

A

citrate -dex = 21 days

with phorphate = 28 days

above with adenine = 35days

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142
Q

what is the advantage of citrate-adenine-phsophate dextrose as a RBC solution for storage?

A

adenine is able to increase RBC ATP and hence survival to 35 days

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143
Q

how much more potent is alfentanil than morphine?

A

10x more

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144
Q

what is the Vd of alfentanil?

A

0.6L/Kg

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145
Q

what is the frequency of ECG in diagnostic and monitoring mode?

A

0.05-100/150Hz = diagnostic
0.5-40Hz = monitoring

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146
Q

which agent produces compound A?

A

sevo

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147
Q

which inhalation agent DOESNT produce CO?

A

SEvo

iso, enflurane and des all do

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148
Q

mechanism for morphine tolerance?

A

uncoupling of G protein from GPCR seems to predominate as the cause

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149
Q

how is the Ga subunit of a GPCR turned off?

A

Ga has GTPase activity which will catalyse the GTP to GDP to limit the reaction and deactivate/ turn off signally.

150
Q

what is a kinase and phosphatase?

A

kinase - adds P = phosphorylases a substance

phosphatase = removes P

151
Q

2 ways to size a guedel?

A

Either distance from midpoint of incisors to angle of mandible, or distance from the corner of the mouth to the tragus.

152
Q

what nerves are blocked by a transversus abdominis plane block?

A

TAP block
ilioinguinal
iliohypogastric
subcostal

153
Q

what is the mechanism of halothane hepatitis?

A

trifluroacetyl metabolities bind liver proteins –> autoantibodies

leads to centrolobular necrosis

154
Q

how is weight estimated from age of a child?

A

age + 4
multipled by 2

155
Q

what is the size of an LMA based on weight?

A

3 = 30 to 50kg (20ml cuff volume)
4= 50 to 70 kg (30ml cuff vol)
5 = 70-100kg (40ml cuff vol)

1 = up to 5kg (4ml)
1.5 = 5-10kg (7ml)
2 = 10-20kg (10ml)
2.5 = 20-30kg (14ml)

156
Q

symptoms of high lithium?

A

COURSE tremor
N&V
ataxia
loss of conscioussness
seizures
nystagmus
hyperreflexia

157
Q

what mechanism of a filter will filter viruses?

A

viruses are small 0.1um

rely on brownian diffuison (<0.5um)

158
Q

what are the methods of which a filter can filter particles?

A

gravitational settling >5um
inertial impaction - 0.5 to 1um
interception - 1um
brownian diffusion <0.5um
electrostatic interaction

159
Q

define magnetic flux?

A

measurement of total magnetic field passing through a given area

160
Q

at what point is the absorption specta of carboxyHb similar to other Hb?

A

similar to oxy Hb at 660

(this doesnt mean oxy Hb has greatest absorption at 660 - deoxy still does)

161
Q

how much bile produced each day? can it undergo 1st pass metabolism?

A

600ml
yes reabsorbed at terminal ileum (90%) as secondary bile acids (bacteria modify hydroxyl groups). then undergo 1st pas metabolism

162
Q

what is the dose of phenytoin in kids?

A

20mg/kg
over 20 mins
ecg monitoring

163
Q

what is dose of levetiracetam in kids?

A

30-60mg/kg - max 3g

164
Q

causes of raised anion gap?

A

10-20 is normal - mudpiles

methanol
uraemia
DKA
Propylene glycol
Iron, isoniazod
lactate
ethanol, ethylene glycol
salicylates

165
Q

what happens with halothane and rubber?

A

halothane is absorbed into rubber.
if this is present in the circuit, it can reduce amount delivered to patient.

166
Q

where does the anterior scalene attach to 1st rib?

A

anterior scalene attaches to scalene tubercle of 1st rib

167
Q

how is sux apnoea inherited?

A

recessive
chrom 3

168
Q

what is prefered for a fascia iliaca block - low or high vol?

A

high volume block

169
Q

name 2 primary and 2 secondary bile acids…

A

primary = cholic acid and chenodeoxycholic acid

secondary = lithocholic acid and deoxycholic acid.

170
Q

what is the pathophysiology of heparin induced thrombocytopenia?

A

IgG antibodies to platelet factor 4 / heparin complex
leads to thrombus formation and destruction of platelets

170
Q

where in the airway do particles get filtered depending on size?

A

upper airway = 40um
bronchi = 8-15um
peripheral conducting airway 3-5um
alveoli = 0.8-3um

170
Q

what are the 4 Ts to estimate likelihood that a fall in platelet count is caused by heparin induced thrombocytopenia?

A

timing

magnitude of platelet drop

thrombosis or other sequale

potential for other causes of thrombocytopenia

171
Q

what is the minimum efficiency size of a filter (that filters particles)?

A

0.3um

172
Q

what is the purpose of the selectatec interlock system on the vapouriser?

A

ensures only one vaporiser can be fitted at a time

173
Q

what tracheostomy should not be used in patients with high aspiration risk?

A

a fenestrated tube should be avoided

174
Q

what tracheostomy tube is safest to use in those cared for out of tracheostomy specialised areas?

A

uncuffed - prevents risk of cuff herniation.

175
Q

what type of tracheostomy should be used if invasive ventilation is to continue

A

cuffed tube

176
Q

how do antifungals work?

A

mostly by inhibition of ergosterol synthesis or membrane function

azoles - inhibit formation of ergosterol

polyenes bind ergosterol and create pores in membrane

echinocandins - inhibit B1-3 glucan synthease in fungal membrane

177
Q

cat 1 C section for fetal brady, Cant intubate, get i gel in. what next?

A

continue with C section with cricoid on

178
Q

how much csf proced each day?

A

450ml
(150 ml present at one time)

179
Q

what is the response time of a thermistor like? how sensitive is it?

A

slow
very sensitive
fragile

180
Q

what are the advantages and disadvantages of a side stream gas analyser?

A

advantages - less bulky so can be used in prone, can be used in awake patients, light weight

disadvantage - lag time, possible tube obstruction, water vapor pressure can change ETCO2 concs, moisture trap needed, pressure drop can affect readings

181
Q

what are the pros/cons of mainstream sampling gas analysis?

A

pros - less chance of obstruction, no lag, no pollution effects, no effect of water vapour pressures

cons - bulky, hard to use in prone , increased risk of patient cross contamination,

182
Q

what are the side effects of cimetidine?

A

CYP450 inhibitor
anti-androgen effects - impotence, gynacomastia and reduced sperm count.

183
Q

where does the larynx sit in children vs adults?

A

adults = C3 to C6
children = C2/C3

184
Q

what happens if you cant pass a suction catheter down a trachea and patient not ventilating?

A

deflate the cuff - they can potentially orally oxygenate

185
Q

which is the only agent increasing cerebral blood flow?

A

ketamine
(and hence increase in ICP)

186
Q

what electrolyte changes are seen in furosemide?

A

low, K, Mg, Ca
Can cause hypernatraemia

187
Q

what is engraved on cylinders?

A

date of test
test pressure
chemical formula of gas
tare weight

188
Q

what does the shape and colour of the plastic disc on the neck of a cylinder indicate?

A

year of inspection

189
Q

what are U1 and U2 opioid receptors responsible for?

A

U1 = analgesia and dependance

U2 = resp depression, reduced peristalsis, miosis and euphoria

190
Q

what are the 3 phases of gastric acid secretion?

A

cephalic (30%) - anticipation of food - vagal response to cause motility and gastric juice secretion

gastric phase (60%) - gastric distension- vagal response. peptides - gastrin release

intestinal phase (10%) - duodenal distension and presence of peptides and amino acids - more gastrin.

191
Q

what inhibits gastrin release?

A

secretin = released from S cells in duodenem due to acidity

somatostatin = released by D cells of stomach when pH <2

192
Q

what is the equation for length of tube in children?

A

age / 2 +12

193
Q

how is odds ratio calculated for the following…

2 people out of 12 got disease after treatemtn

5 people out of 12 got disease in non-treatment group

A

treatment group:
2 people diseased, 10 people without = 2/10
non treatemtn
5/10

overall odds ratio 0.2/0.5 =0.4

194
Q

what is the pressure of:
- piped O2 /N20/ Air
- cylinders of O2 and entanox
- cylinder of N20
- air for driving tools in pipeline

A
  • 4 bar
  • 137 bar
  • 52 bar (at 20 degrees), 44 bar at 15 degrees.
  • 7 bar
195
Q

what is the max leakage current for CF devices?

A

single fault = 50uA
multiple = 10uA

196
Q

which esterases are the following drugs metabolised by? aspirin, esmolol, sux/mivacurium, remi, local anaesthetics

A

asprin = hepatic and intestinal esterases
mivacurium/sux / Local A= plasma cholinesterases
remifentanil - non specific plasma / tissue

esmolol = red cell esterases

197
Q

how is relative risk reduction calculated?

A

calculate % in each group
find difference = absolute risk reduction

divide difference by control group %

198
Q

what is included in turbulent flow equation?

A

Flow is proportional to the square root of the pressure gradient

Flow is proportional to the radius squared

Flow is inversely proportional to the square root of tube length

Flow is inversely proportional to the square root of fluid density

199
Q

name some different phosphodiesterase inhibitors?

A

milronone, enoximone = selective for PDE III

sildenafil and dipyramidol = PDE V

aminophylline/ theophylline = non selective

200
Q

how much more lipid soluble and potent is fent than morphine?

A

x100 more potent
x600 more soluble

201
Q

what is the narrowest part of the airway in children?

A

level of crircoid cartilage

adults = laryngeal inlet.

202
Q

how does basal oxygen consumption and MV compare in children to adults?

A

increased basal O2 consumption

increased MV (100ml/kg/min in children, 60ml/kg/ min adults)

203
Q

how does an intra-aortic balloon pump work?

A

balloon inflated in early diastole, just after aortic valve closure and remains inflated until aortic valve opens again.

this means
- higher early diastolic pressure and improved perfusion of organs
- deflation when aortic valve opens so that reduced afterload

204
Q

for aortic doppler. how is the flow time corrected calculated?

if this is low/high what does it suggest?

A

flow time / root cycle time

flow time is the duration of forward flow of blood.

low value = hypovolaemia, mitral stenosis or P.E

high = vasodilated circulation e.g. sepsis.

normal flow time corrected = 330 to 360ms

205
Q

what does vit B12 bind to in plasma?

A

Transcobalamins

206
Q

what does haemopexin bind to in plasma?

A

free haem

207
Q

what is a cardiff aldasorber?

A

passive scavenger
for anaesthetic agents
(not CO2 or N20)

208
Q

what amp output does nerve stimulator use in nerve blocks?

A

initially 1-3mA
as it gets constractions, reduce output
if 0.3-0.5 it is very close

<0.2mA = intraneural

209
Q

what is the mechanism of nicrorandil?

A

ATP sensitive pottasium channel activator - hyperpolarisation and relaxation of arteriole.

210
Q

what was the issue with Tec 2 method of temp compensation?

A

bimetallic strip within vapouriser

Preservative such as thymol in halothane could cause the bimetallic strip to stick adversely affecting its function and inhalational agents could cause the bimetallic strip to corrode.

211
Q

what happens to lung volumes in pregnancy?

A

reduction in FRC
reduction in chest wall compliance
closing bolume begins to aproach FRC
TV increases by 45%

total lung and vital capacity - unchanged.

212
Q

what is the breakdown product of noradrenaline?

A

VMA
by comt and Moa

213
Q

how is noradrenaline formed?

A

from dopamine
via dopamine hydroxylase

214
Q

what chains make up fetal Hb?

A

2 alpha
2 gamma

215
Q

what is HbA1 and HbA2?

A

HbA1 = 98% of adult Hb = 2 alpha and 2 beta

HbA2 = 2% of adult Hb = 2 a and 2 delta

216
Q

what is the max absolute humidity at 37 degrees?

A

44 g/m3

217
Q

what is the efficiency of a HME filter? what humidity can it achieve at 37 degrees?

A

at 37 degrees = max absolute =44g/m3

efficiency of HME = 60-70%

hence humidity = 26-30g/m3

218
Q

intubated patient=
Tidal volumes = 500 ml
PaCO2 measured at 5 kPa
expired PCO2 measured as 4 kPa.
A catheter mount was introduced to increase the dead space and expired PCO2 was re-measured as 3 kPa.

What is the volume of the catheter mount assuming PaCO2 does not change?

A

VD/VT = (PaCO2 - PECO2)/ PaCO2

difference between 1/5th

1/5th of VT = 100ml

219
Q

how does trimetaphan work?

A

blocks nAChR
reduces BP by acting centrally and blocking ganglionic transmission.

220
Q

how does methyl dopa work?

A

stimulates alpha 2 receptors

221
Q

name 4 drugs causing gynaecomastia..

A

spironolactone
digoxin
isoniazid
cimetidine

222
Q

how long is the cardiac action potential?

A

300ms

223
Q

what is the role of the pilot balloon on ET tube?

A

The pilot balloon provides a visual and tactile representation of endotracheal cuff integrity. It is attached to a spring loaded one-way valve which allows inflation of the cuff and prevents escape of air.

has a role in cuff inflation but purpose of it being a balloon is for the above.

224
Q

what should ET tube cuff pressure be?

A

low pressure high vol

20-30cmH20

225
Q

what important DDI does linezolid have?

A

acts as a weak non selective MAO inhibitor
hence can precipitate HTN crisis/ serotonin syndrome

226
Q

what is the action of levosimendan?

A

calcium sensitizer in cardiac muscle
sensitiser cardiac muscle fibres to calcium and increases contractility without increase in O2 consumption.

227
Q

which local anaesthetic can cause methamoglobinaemia?

A

prilocaine
due to o toludine metabolite

228
Q

which needles can be used in spinal and why?

A

sprotte and whitacre

both pencil point
improve tactile touch
reduce incidence of post puncture dural headache

can also use a quincke needle = cutting needle - easier to penetrate and quicker to give CSF return but more risk.

229
Q

what is the Dibucaine test?

A

assess’s sux apnoea

dibucaine is a local anaesthetic that inhibits plasma cholinesterases if the cholinesterase is normal.

benzylcholine is given as a substrate for cholinesterases and when metabolised, light is released and detected.

In order to perform the test, the patient’s plasma is added to a mixture of benzylcholine and the light emitted is detected. Then, dibucaine is added and the light is measured again.dibucaine only inhibits normal pseudocholinesterases.

a normal response reduces light emission by 80% i.e. dibucaine number of 80.

230
Q

what are the borders of the cubital fossa?

A

Superior: A line connecting the medial and lateral epicondyles

Lateral: Medial border of brachioradialis

Medial: Lateral border of pronator teres

Floor: Proximally by brachialis, distally by supinator

Roof: A combination of skin and fascia including the bicipital aponeurosis

231
Q

what is the absolute humidity at 20 degrees?

A

17 g/m3

232
Q

how much adrenaline in anaphylaxis by age?

A

0-6month = 100mcg
6 months - 6yrs =150mcg
6yrs -12 yrs = 300mcg
12 yrs + = 500mcg

IM 1:1000 e.g. 0.1ml = 100mcg

233
Q

what is the dose of adrenaline in an arrest in paeds?

A

10 mcg/kg
e.g. 0.1ml /kg of 1:10000

234
Q

state the cyp450 inducers and inhibitors…

A

Inducers – PC BRAS – Phenytoin, Carbamazepine, Barbiturates, Rifampicin, Alcohol (chronic)/, Sulfonylureas/ st johns

Inhibitors – GOA DEVICES – grapefruit
Omeprazole, amiodarone/antifungals, Disulfiram, Ethanol (acute), Valproate, Isoniazid, Cimetidine, Erythromycin, Sulfonamides. amiodarone too
,

235
Q

what are the guidelines for HTN at elective surgery?

A

proceed if <160/100mmHg in primary care

on day of surgery acceptable to be up to 180/110

236
Q

how long is autoclaving performed for?

A

steam sterilisation via autoclave

temperatures of 121 ºc for 30 minutes OR 132 ºc for 4 minutes at a pressure of 2.25 bar.

237
Q

what is the mechanism behind cardio and neurotoxicity in TCA overdose?

A

their interaction with VG Na channels

238
Q

how is protein binding in TCA overdose increased?

A

Protein binding is increased in alkaline blood, and therefore in those with a significant overdose, a plasma pH of 7.5-7.55 can help this

239
Q

what is the induction dose for etomidate?

A

0.3mg/kg

240
Q

which roots and cord does the ulnar nerve come from?

A

C8 to T1
medial cord

241
Q

what is the sural nerve?

A

formed from both the common peroneal and tibial nerves,

purely sensory

to the posterolateral leg and the lateral aspect of the foot.

242
Q

what is sucralfate?

A

non absorbable aliminium salt
acts as an antacid and forms a physical barrier to protect mucosa.

may redcuce absorption of other drugs e.g. warfarin

243
Q

how does nitrous oxide lead to problems chronicaly

A

interfere with the cobalt ion on the vitamin B12 complex,

which subsequently interferes with the function of methionine synthase

leads to megaloblastic anaemia, and can also lead to subacute combined degeneration of the cord.

244
Q

pathway for NA and adrneline production…

A

tyrosine –> LDOPA (tyrosine hydroxylase)
LDOPA –> dopamine (L DOPA decarboxylase)
dopamine –> NA (dopamine hydroxylase)
NA –> adrenaline (PNMT)

245
Q

what is the difference between giving dopamine at low and high doses?

A

At low doses (1-5 mcg/kg/min), dopamine receptors are activated.

At intermediate doses (5-10 mcg/kg/min), beta-1 receptors are activated.

At high doses, alpha-1 agonism occurs

246
Q

what % does renal blood flow increase in pregnancy?

A

50%

247
Q

which hormone has ADH like activity?

A

oxytocin

248
Q

what is the half life of ADH?

A

5 mins

249
Q

which enzyme converts NA to adrenaline

A

PNMT (phenylethanolamine N-methyltransferase)

250
Q

what would
- tricuspid stenosis
- tricuspid regurg
- complete HB

show on JVP?

A

Tricuspid stenosis can lead to large a waves, as more pressure is required to shunt blood through the narrowed orifice

Complete heart block can lead to Cannon A waves due to atrio-ventricular dysynchron

tricuspid regurg - large V (also large c)

251
Q

name drugs used for SVT, VT and both

A

Supraventricular only: digoxin, verapamil, adenosine.

Ventricular only: lidocaine, phenytoin.

Both: amiodarone, beta-blockers, disopyramide, procainamide, fleicanide.

252
Q

name 2 B2 agonsits

A

salbutamol
terbutaline

can give either in asthma

253
Q

contraindications to epidural spinal?

A

patient refuses

infection at the site or sepsis

hypovolaemia - severe

aortic stenosis / HOCM

increased ICP

coagulopathy

254
Q

how should methadone be managed perioperatively?

A

continue

255
Q

what are the contraindications to an aortic balloon pump?

A

severe aortic regurgitation
Aortic dissection
sepsis
severe peripheral vascular disease.

used post cardiac surgery to support failing heart whilst awaiting definitive management

256
Q

name agents to
- estimate total body water
- ECF
- plasma
- red cell volume

A

Deuterium oxide – Total body water
Inulin – Extracellular fluid
Plasma – Radiolabelled albumin, Evan’s blue
Red cell volume – Radiolabelled red cells

257
Q

colour coding of inhaled anaesthetic agents…

A

Red – halothane
Purple – isoflurane
Yellow – sevoflurane
Blue – desflurane
Orange – enflurane

258
Q

state the respiratory quoient for different diets?

A

fat is 0.7, for protein 0.8, and for carbohydrate 1.0.

259
Q

how does GABAPENTIN work?

A

blocks L type Ca channels

also modulates GAD which increases levels of GABA

260
Q

what is oral bioavailability of tramadol like?

A

90%
similar IV and oral dose

261
Q

does tramadol have isomers

A

yes exists as racemic mixture

262
Q

explain the pathway for adrenaline and norad production

A

tyrosine –> L dopa (tyrosine hydroxylase)

L dopa –> dopamine (dopa carboxylase)

dopamine –> NA (dopamine hydroxylase)

NA –> adrenaline (PNMT)

263
Q

how is TPN calculated?

A

30-40ml/kg / day = fluid

30kcal/kg/day - medical
45 cal/kg/day - post op

protein - 1kg/day post op

264
Q

what does pregnancy do to MAC?

A

decreases it

265
Q

where do osmotic diuretics work?

A

loop of henle (and PCT)
e.g. mannitol

266
Q

where does amiloride work?

A

DCT

267
Q

describe management of diabetes for surgery where there is no more than 1 missed meal?

A

levemir/ lantus/ tresiba (long acting)
- reduce day before to 80%
- if morning dose normally taken - also reduce this by 80%
- continue at 80% if VRII being used

those for twice daily injections - half morning dose e.g. novomix 30, humulin

short acting given with meals - omit dose before surgery and until meals

take all oral hypoglycaemics as normal day before
DDP4, metformin, GLP1, pioglitazone - take as normal
all others omit on day of surgery.

268
Q

safe dose of prilocaine?

A

6mg/kg

269
Q

what actions does amitriptlyine have?

A

antagonistic action at other receptors: 5-HT, α1 adrenergic, NMDA, H1, H2 and mACh.
NA/5HT3 reuptake inhibitor

inhibit cardiac sodium and calcium channels

270
Q

how is numbers needed to treat calculated?

A

The number needed to treat is 1/ARR

ARR = incidence in control group – incidence in treatment group
e.g. % -%

271
Q

which is quicker capnography or pulse oximetry?

A

capnography - delay of around 3 seconds
pulse ox = 20sec

272
Q

is gluconeogesis aerobic or anaerobic?

A

anaerobic

273
Q

what happens to flow in variable intrathoracic obstruction? extrathoracic?

A

intrathoracic = inspiratory flow preserved

extrathoracic = expiratory flow normal , insp reduced

Fixed large airway obstruction has reduced flow in both inspiration and expiration.

274
Q

what is larger peak exp or peak insp?

A

In health, the peak expiratory flow rate exceeds that of inspiration.

275
Q

what is the function of fusidic acid?

A

inhibits protein synthesis - ribosomal function.

276
Q

how does B2 result in bronchial smooth muscle relaxation?

A

Gs, cAMP, PKA, MLCkinase inactivation ! also indirectly activates MLCphosphatase

277
Q

what are the advantages of biphasic defib?

A

Able to compensate for wide variations in thoracic impedance by adjustment in waveform magnitude and duration

lower peak current delivered

less energy for defib

improved safety

278
Q

positions on pacemaker….

A

1 = chamber paced - V, A, Dual, 0=none
2 = chamber sensed - as above
3 = mode of response - triggered, inhibited, D (either or)
4 = programmable functions - R (rate modulated), C (communicating), M multiprogramme, P simple
5 = anti tachycardia functions (none, paced, shock, D = paced and shocks)

279
Q

what rate does a wrights respirometer rotate? which part of breathing circuit is it positioned?

A

150 revolutions per litre of gas flow

expiratory limb

280
Q

how will wrights respirometer work at low TV?

A

under estimate due to friction

281
Q

what can suggamadex be used for?

A

roc
vec
(more effective with roc)

282
Q

which diuretics work in Distal convoluted tubule?

A

Early distal convoluted tubule: thiazide diuretics.

Distal convoluted tubule: amiloride

283
Q

which structures do the roots of the brachial plexus pass when exiting the neck?
what structures do they run with after this?

A

anterior and middle scalene muscles
then run in close proximity to subclavian artery

284
Q

how long does a battery pacemaker typically last?

A

8-10 yrs

285
Q

what is this…

A

halothane
Mr = 197

286
Q

what does hamburger shift describe?

A

he Hamburger (or chloride) shift exchanges a bicarbonate ion from the red cell for a chloride ion from the plasma, in order to maintain electrochemical neutrality.

287
Q

what is the respiratory exchange ratio?

A

he respiratory exchange ratio (RER) is the ratio of CO2 production to oxygen uptake. Usually, this is around 0.8, with some variability depending on diet.

hence amount of CO2 made usually less than O2 consumed

288
Q

what is the ideal blood pressure cuff size?

A

blood pressure cuff bladder length is ≥ 80% of the patient’s arm circumference and the width is ≥ 40% of the patient’s arm circumference.

289
Q

what is special about GTN infusions during set up of the infusion?

A

need polyethylene syringes and giving sets.
GTN is absorbed onto PVC bags and giving sets, therefore it is important to use glass bottles or polyethylene syringes and infusion lines.

same for sodium nitroprusside

290
Q

which infusion should you avoid sunlight with?

A

sodium nitroprusside
need to wrap giving sets in tinfoil

otherwise liberation of cyanide ions

291
Q

what do you dilute sodium nitroprusside in?

A

5% dextrose

292
Q

what can increase damping within arterial blood pressure system?

A

Loss of pressure
soft compliant tubing
numerous connections
narrow gauge cannula
kinking of the cannula
use of a compliant transducer diaphragm
blood clots and air bubbles within the system

293
Q

is halothane hepatitis more common in adults or children?

A

adults

risk factors
obesity, female sex, pre-existing liver disease and repeated exposure to halothane.

294
Q

how is O2 content calculated?

A

(1.34 x Hb x SpO2) + (0.0225 x PaO2)

0.003 for mmHg

295
Q

what is larmor frequency?

A

rate of precession of a magnetic moment

depends on magnetic field stretnght and the gyromagnetic ratio

296
Q

how is type 1 basal bolus insulin managed for surgery?

A

missing 1 meal = give normal basal insulin, omit morning and lunchtime short acting

missing 2 meals = VRII

297
Q

colours of filters on breathing machines…

A

yellow – breathing filters microbes
Blue – heat and moisture exchange.
Green – both

298
Q

which antibiotic causes peripheral neuropathy?

A

nitrofurantoin & metronidazole & ciprofloxacin

irreversible

299
Q

mechanism of
dipyramidole
tirafiban
clopidogrel

A

dipyramidole - phosphodiesterase
Clopidogrel - ADP (P2Y12 receptor)
tirafiban - GPIIb/IIIa

300
Q

how is pulmonary vascular resistance calculated?

A

Pulmonary vascular resistance = 80 x (Mean pulmonary artery pressure – Left atrial pressure)/Cardiac output.

Left atrial = Pulmonary capillary wedge pressure

answer in dyne.s-1.cm-5

301
Q

define mixture…

A

2 or more substances dispersed through one another whose consituent parts retain their original identity

302
Q

define solution

A

solvent and solute combine to make a new homogenous substance. not a mixture

303
Q

define suspension

A

A suspension is two or more substances mixed together where the heavier substance will eventually settle out under gravity.

304
Q

define colloid

A

A colloid is a type of mixture where a substance is evenly dispersed through another which will not settle out under gravity.

onsists of an internal phase (small particles) and an external phase through which internal phase is dispersed.

can be liquid, solid, gas

305
Q

define emulsion

A

a ‘liquid in liquid’ colloid or a colloidal mixture of two or more immiscible liquids. Energy input is required from shaking or stirring and emulsifiers may be used to provide stabilisation.

306
Q

what is the normal systemic vascular resistance value?

A

800-1600 dyn.s.cm-5

307
Q

in pregnancy what is main cause of increased CO?

A

Stroke volume (due to preload)

also some increase in HR (25%) but mostly SV (30%)

308
Q

what is the advantage of the miller blade?

A

straight blade
used in paeds to lift epiglottis out the way

309
Q

what % receptors occupied per ToF count?

A

0 twitches = 95-100%
1 twitch = 90%
2 twitch = 80%
3 twitches = 70%
all twiches <70%

310
Q

what is function of long inlet port on the vapouriser?

A

prevent bypass channel becoming contaminated with retrograde flow

311
Q

why are equal volumes used in bypass channel and vapourising chamber?

A

ensure any gas expansion is equal .

312
Q

how do saline filled lungs change compliance?

A

reduces surface tension hence increases compliance

313
Q

how do basal alveoli and apical alveoli compare on compliance curve?

A

Basal alveoli are less distended at rest than apical alveoli, and so are on a steeper part of the compliance curve.

314
Q

define sterilisation

A

The process of rendering an object free from all pathogenic organisms including bacterial spores

315
Q

define disinfection…

A

Disinfection: The process of rendering an object free from all pathogenic organisms except bacterial spores

316
Q

which organelle is highly present in Z3 of liver?

A

Smooth endoplasmic
for drug metabolism.

317
Q

what is the hepatic artery a branch of?

A

coeliac trunk

318
Q

what wavelength do different lasers use?

A

argon = 400-600nm - blue/green - opthalmic surgery

NAD-YAG - 1060nm - endoscopic and oesophageal varices

CO2 - 10600nm - poor tissue penetration, superficial airway surgery

319
Q

what is the atm pressure at 5500 meters?

A

50 kpa
roughly 0.5atm

320
Q

what is a notch filter and bandwidth filter?

A

notch filter = removes specific wavelength
bandwidth = allows through band of wavelegnth

321
Q

what current is delivered in PTC?

A

50Hz 5 seconds
followed by 3 second pause
1 hz x 20 stimuli

322
Q

which electrodes are seen in pH measurements ?

A

reference electrode = mercury / calomel (or Ag/AgCl) + KCL

measuring = Ag/Agcl, buffer solution

323
Q

what is meant by population inversion in LASER?

A

state where lasting medium where more atoms are high energy state than ground energy state

324
Q

what does a sieving coefficient of 1 mean?

A

freely filters across and equilbriates with plasma e.g. glucose

325
Q

what is iloprost used for?

A

prostacylin analogue - potent pulmonary vasodilatory

given inhaled and hence goes preferentially to ventilated alveoli

improves V:Q
can also be used in pulmonary HTN

326
Q

name 3 types of meds used in pulmonary artery HTN

A

endothelin antagonists = bosentan, ambrisentan

prostacyclin agonist = iloprost, epoprostenol

PDE5 inhibitors = sildenafil

327
Q

what is a supramaximal stimulus?

A

A supramaximal stimulus is typically 25-50% higher than that needed to produce a maximal response.

328
Q

why is having an increased horizontal width beneficial of an i gel?

A

prevents rotation

329
Q

which nerves are blocked in an axillary nerve block?

A

ulnar, radial, median, musculocutaneous

the musculocutaneous lies away from the other 3 and needs redirection of needle for local injection

330
Q

how does erythromycin work as a prokinetic?

A

mimics motilin
agonist at motilin receptors

331
Q

which conditions lead to inaccuracies of wedge pressure estimating LA pressure

A

mitral stenosis/ regurgitation
atrial myxoma
pulmonary veno occlusive disease
cardiac tamponade

332
Q

state the laws of thermodynamics?

A

0th - two thermodynamic systems are in equilibrium with a third then they are also in equilibrium with each other.

1st - energy can neither be created or destroyed only converted from one form to another.

2nd entropy tends to increase with time.

3rd - as a system approaches absolute zero (-273.15ºc) all processes cease and entropy approaches a minimum.

333
Q

how does Calcium conc compare in CSF to plasma?

A

lower in CSF

334
Q

how does Mg compare in CSF to plasma

A

higher in CSF

335
Q

name phase 1 reactions in liver

A

by CYP450
oxidation, reduction, hydrolyiss

dealkylation and deamination

336
Q

how does rate of elimination compare to clearance?

A

rate of elim = clearance x plasma conc

337
Q

what do I cells of stomach secrete?

A

Cholecystokinin

338
Q

why does renin rise in HF with low ejection fraction?

A

In response to the likely decreased cardiac output, sympathetic tone will be increased due to the activity of baroreceptors. In turn, this will lead to increased renin release.

339
Q

what should stroke volume variation % be to be fluid responsible

A

if <10% unlikely fluid responsive

340
Q

how do lisinopril and enalapril vary in metabolism?

A

enalapril - prodrug, metabolised by liver
lisinopril not metabolised, excreted unchanged

341
Q

How does pethidine solubility and potency compare to morphine?

A

relative lipid solubility x 30 t

relative potency x 0.1 that of morphine.

342
Q

how does ephedrine work?

A

Within the neuron, ephedrine exchanges with noradrenaline via VMAT

causes release noradrenaline into the synaptic cleft, which stimulates α1 adrenoreceptors leading to vasoconstriction

343
Q

target CO2 in head injury?

A

4.5-5 kPa.

344
Q

what is the effect of bicarb on local anaesthetics?

A

sometimes added to increase unionised form

345
Q

what is more potent lidocaine or bupivacaine?

A

bupivacaine

346
Q

compare lipid solubility of fentanyl and alfent?

A

fent = 600x morphine
alfent = 90x morphine

347
Q

what is more potent alfent or fent?

A

fentanyl

348
Q

what is purpose of bodok seal?

A

It is found on the anaesthetic machine between the valve block and the yoke in order to prevent gas leak.

349
Q

mechanism of ciprofloxacin?

A

fluroquinolone
DNA gyrase/ topoisomerase inhibition - DNA synthesis inhibition

350
Q

mechanism of rifampicin

A

RNA polymerase inhibition

351
Q

mechanism of aminoglycosides? example drug?

A

gentamicin
30S inhibition

352
Q

erythromycin class?mechanism

A

macrolide
50S inhibition

353
Q

cannula flow rates…

A

14G (orange) 270 ml/min.
16G (grey) 180 ml/min.
18G (green) 80 ml/min.
20G (pink) 54 ml/min.
22G (blue) 31 ml/min.

354
Q

what koratkoff does diastolic and systolic correspond to?

A

In the UK, systolic blood pressure corresponds to phase I, diastolic blood pressure to phase IV (phase V in the US).

355
Q

what is Aliskiren?

A

direct renin inhibitor
prevents angiotensinogen to angiotensin 1

356
Q

equation for loading dose…

A

Loading dose (mg) = concentration (mg/ml) x volume of distribution (ml)

357
Q

what is T1 and T2 relaxation in MRI?

A

T1 = spin lattice relaxation - time taken for rotated net magnetism to realign with main magnetic field.

T2 = spin spin relaxation - time taken for a loss of phase coherence of net magnetism following rotation of net magnetism

both negative exponential process
and are different depending on tissue

358
Q

safety features of Tec 6?

A

9V battery in case of mains failure

audio-visual alarms

a rotating filling port (preventing filling during use)

mounted using the Selectatec system.

The % control dial is from 0-18%, in divisions of 1% up to 10% and then 2% up to 18%.

359
Q

what blade is the wisconsin blade similar to? when can it be used?

A

Miller
straight blader
used in paeds for getting epiglottis out the way

360
Q

mechanism of labetalol?

A

non specific alpha and beta antagonist.

361
Q

what size mesh do epidural filters have?

A

0.22 microns

362
Q

what is the newton valve?

A

valve used in penlon nuffield so it can be used in paeds by preventing volutrauma.

363
Q

how can an elastomeric pump be turned into a PCA?

A

In elastomeric pump is a single use, low cost, portable infusion pump
basically balloon filled with fluid that slowly empties as the elastic recoil of the balloon

downstream flow restrictor limits flow to patient

may be turned into a PCA through the use of a compressible reservoir downstream of the flow restrictor.

The lock out time is governed by refilling of this reservoir.

364
Q

what is the shunt equation?

A

Qs/Qt =
(CcO2 – CaO2)/(CcO2 – CvO2)

CcO2 = End capillary oxygen content (estimated using alveolar gas equation)
CaO2 = arterial oxygen content (from arterial blood gas)
CvO2 = mixed venous oxygen content (from pulmonary artery floatation catheter sample)
Qt = cardiac output

365
Q

mechanism of action of glibenclamide?

A

sulphonylurea

366
Q

colours for venturi for % O2

A

blue = 24%
white = 28%
orange = 31%
yellow = 35%
red= 40%
green = 60%

367
Q

Difference between Oxford min and Goldman

A

Oxford min
- 50ml volume
- no active temp compensation
- ethylene glycol heat sink
- can be used with any anaesthetic agent by changing the dial on scale

Goldman
- 30ml volume
- no temp compensation/ heat sink
-

368
Q

How many vaporisers in tri service ap?

A

2x Oxford min

369
Q

What is more potent morphine or it’s metabolites ?

A

Morphine 6 glucuronide x13 more potent

370
Q

Order of amount of co2 carried by differnt components in blood

A

Bicarbonate 60%
Carbamino 30%
Dissolved 10%

In arterial blood more is carried by bicarb and less by carbamino due to haldane effect

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