Teach me bank Flashcards
(372 cards)
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.
2
Q
what level of block is required for a C section?
A
block to T4-T5
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.
4
Q
what is Edrophonium?
A
short acting acetylcholinesterase inhibitor
can temporarily relieve myasthenia symptoms
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.
6
Q
when can acetazolamide be used?
A
altitude sickness
glaucoma
metabolic alkalosis
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
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)
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
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
11
Q
how is MAC affected by pregnancy?
A
reduced
12
Q
what type of tilt is recommended in preg to relieve aortovenal compression
A
left lateral
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.
14
Q
how does propofol cause hypotension?
A
Propofol impairs central vasomotor control and has peripheral effects on inhibition of L-type calcium channels.
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
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’
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
18
Q
what does an undersized cuff do to BP readings?
A
overestimate
of systolic AND diastolic
19
Q
which ant acid causes diarrhoea?
A
magnesium trisilicate
(Aluminium containing antacid medications also tend to cause constipation rather than diarrhoea)
20
Q
which antiepileptics are Na channel blockers
A
Phenytoin, carbamazepine and lamotrigine.
21
Q
what is the action of ethosuximide
A
Calcium current inhibitors
22
Q
what contributes to phase 4 of cardiac pacemaker cells?
A
funny current sodium channels and T-type calcium channels
23
Q
what is the max dose of ramipril?
A
10mg
24
Q
what should BP in community be before elective surgery?
A
<160/100mmHg
25
what are the immediate, delayed and late complications of a tracheostomy?
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.
26
what type of current is delivered by TOF?
50mA
2Hz - 1 stimulus every 0.5 seconds
4 in total
each lasts 0.2ms
27
how does a pressure / volume loop look for aortic stenosis?
thinner and narrower
same end systolic volume , reduced SV hence increase in EDV
28
which metabolite of morphine is active?
morphine 6 glucuronide
29
what structure passes through foramen spinosum?
middle meningeal artery
30
which structure passes through the foramen rotundum?
maxillary nerve
31
what structure passes through the optic canal?
opthalmic artery
optic nerve
32
which structure passes through the foramen ovale ?
mandibular nerve
33
which Abx caused most anaphylaxis according to NAP 6?
Teicoplanin and then co amox
34
what is the spaulding classification?
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.
35
what is the absolute humidity of a room at atm presure at 20 degrees?
293 K is approximately 20 ºc, and at this temperature fully saturated air has an absolute humidity of 17 g/m³.
36
how do opioids exert action on receptor?
stimulation of Gi
hyperpolarisation
via K+ efflux
37
with spinal anaesthetic, which antiplatelets should be stopped and when?
aspirin = continue
clopidogrel and prasugrel = 7 days
Ticagrelor – 5 days.
Abciximab – 2 days.
Tirofiban – 8 hours.
38
which GI medication can increase warfarin effects?
cimetidine = H2 antagonist
used for reflux
inhibits CYP450
39
what are the recommended allowance for inhalation agent occupational exposure?
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.
40
in a dose response curve, which axis is logarithmic?
x axis - log dose
y axis - response % of max response
41
how is relative risk calculated?
note not relative risk reduction.
relative risk = % in new drug / % incidence in old drug
42
what is the absolute pressure of a cylinder?
gauge + atm
e.g. 13700 + 101
43
what is the pka, PB and relative solubility of lidocaine, bupivacaine and prilocaine?
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.
44
for LA what determines speed of onset, potency and long lasting?
pka = speed
lipid solubility = potency
PB = lasting effects
45
what is the critical pressure of nitrous oxide?
72 bar
46
what is the volume of CSF in healthy adult?
150ml
Around 500ml produced per day
47
what is the urea cycle?
conversion of ammonia to urea
occurs in hepatocytes - between mitochondria and cytosol
urea can then be excreted
48
what dermatome and myotome is responsible for sensation of anterior thigh and hip flexion
L2
The L2 myotome is responsible for hip flexion and the L2 dermatome supplies the anterior aspect of the thigh.
49
how do B agonists and aminophylline interact?
synergistically
50
what is the root mean square deviation. ?
same as Standard deviation (different name)
51
what is a geometric and arithmetic mean?
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
52
what is the Eustachian valve?
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
53
which diabetic medication is contraindicated in congestive HF. what else is this contraindicated in?
thiazolidinedione e.g. pioglitazone
contraindicated in patients with congestive heart failure, diabetic ketoacidosis and active bladder cancer.
54
what class of drug is tolbutamide
sulphonylurea
55
how much CSF is produced each day in health?
450 ml
(3x normal volume = normal vol is 150ml)
56
in cant intubate, cant oxygenate, what is recommended?
cricothyroidotomy
NOT Tracheostomy
57
when may a mainsteam analyser be used for gas analysis?
neonate - less deadspace, more accurate for smaller volumes
58
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?
transverse abdominis
internal oblique
this is where local acts in a TAP block
59
how does TEG work? (thromboelastography)
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.
60
what are the following parameters in TEG - R time, K time, a angle
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.
61
how is rivaroxaban immediately reversed?
andexanet alpha
OR
prothrombin complex concentrate (Beriplex, 50 units/kg)
62
in infrared spectroscopy, why is a crystal window used for which infrared light passes before sampling chamber?
crystal window is used because glass absorbs infrared radiation
63
in fetal circulation, which structure is important in ensuring oxygenated blood goes preferentially to the brain?
Eustachian valve
64
how many drops of fluid and blood is equivalent to a ml?
20 drops = 1 ml of fluid
15 drops = 1 ml of blood
65
describe components of a circle system..
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
66
what type of chemical are all 4 induction agents?
ketamine = phencyclidine
propofol = phenol
thiopentone = barbiturate
etomidate = imidazole (has an ester link)
67
what are the induction doses of the IV induction agents?
propofol = 1-3mg/kg
thio = 3-7mg/kg
ketamine = 1-2mg/kg
etomidate = 0.3mg/kg
hence etomidate 10x more potent
68
what are the pka values of induction agents?
propofol = 11
etomidate = 4
thio = 7.6
ketamine = 7.5
69
of the IV induction agents which has smallest Vd?
largest propofol = 4mg/lg
smallest thio = 2.5mg/kg
ket and etomidate = 3mg/kg
70
what are the design features of the ET tube that enhance safety?
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
71
what is the mechanism of tirafiban?
glycoprotein IIb / IIIa antagonist - antiplatelet
blocks platelet aggregation
72
give examples of ADP receptor blockers...
clopidogrel
prasugrel
ticagrelor
inhibit platelet activation
73
which antibiotics can worsen weakness in myasthenia gravis?
aminoglycocides - gentamicin, streptomycin
macrolides - clarithromycin, azithromycin etc
fluroquinolones - ciprofloxacin
74
which receptors do clonidine and dexmedetomidate bind?
both A2 agonsts
but clonidine also has A1 receptor activity and hence causes some HTN initially (paradoxical HTN)
75
what is the formula for cuff size of ET tube in children?
age / 4 + 4
76
what parts of spinothalamic tract carry what sensations?
lateral = temperature + pain
anterior = crude touch and pressure
(dorsal = light touch, vibreation , proprioception)
77
what is newtons 1st 2nd and 3rd law?
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.
78
what is the catheter mount in a breathing circuit?
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
79
what is the primary intracellular buffer?
phosphate
80
what is the urinary buffer?
phosphate
ammonium
bicarb
81
what are the cathodes and anodes of a galvanic fuel cell?
LAG = lead anode, gold cathode
82
what can Piezoelectric quartz crystal oscillation be used for?
volatile anaesthetic measurement
83
which vessels does GTN act on?
low dose - veins / capacitance vessels - decreased preload , compensatory tachycardia
high dose - arteriolar dilation - reduced afterload
84
what is damping coefficient for optimal damping?
0.64
85
whats the ratio of adrenaline/NA release by adrenals?
80:20
more adrenaline
86
what type of filter is used in anaesthesia/ intesive care for patients breathing system?
HME PLUS pleated hydrophobic filter (antimicrobial and more efficient than electrostatic)
87
what is reactance, impedance and resistance?
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.
88
what is the action of dopamine in CVS pharmacology?
at low dose = D1 and D2 agonist - increased renal blood flow
at larger doses = beta agonist = positive ionotropy
high doses = alpha adrenoreceptor - vasoconstriction
89
what is pralidoxime?
antidote for organophosphate poisoning
90
in pressure swin adsorption for concentrating oxygen what chemical is used to remove the nitrogen
Zeolite = aluminium and silica crystals
91
what does a wrights respirometer measure?
expiratory volumes
92
what size of particles are deposited where in the lungs?
upper airways - 20um
tracheobronchial tree = 2-5um
alveoli - 0.8 to 3um
below 1um - inhaled and exhaled
93
which dural sinus does the IJV originate from?
sigmoid sinus
exits via jugular foramen
94
what is protein binding of digoxin and amiodarone like?
high - one can displace the other leading to toxicity
95
why are children more prone to bradycardia in theatre?
increased parasympathetic tone
more affected by vagal stimulation
96
what is the mechanism of cangrelor? how is it given
reversible ADP inhibitor
given IV
rapid onset and quick recovery
97
what is the safe occupational exposure of halothane?
10ppm
98
what is the onset and duration like for prilocaine? what is the protein binding like? pKA?
rapid onset
medium duration
55% PB
Pka 7.7
99
what is the Vd of ketamine?
3L/kg
100
what is the half life of amiodarone?
long
up to 100days
101
what is the dose of amiodarone?
loading = 300mg over 1 hour
then = 900mg over 24 hrs
102
what is the typical value of pulmonary capillary wedge pressure?
6-12 mmHg
103
what are typically values of right atrial pressure, right venticle pressure, pulmonary artery pressure, wedge pressure??
right atrium = 0 to 5mmHg
right ventricle = 20-30/ 0-5mmHg
pulmoanry artery = 20-30/ 10-20mmHg
wedge = 6-12mmHg
104
what is reflux and siphoning in drug infusion pumps?
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.
105
how is pulmonary vasc resistance measured?
PVR = 80 x (Mean pulmonary artery pressure - LA pressure)/ CO
units dyne.s-1.cm-5
106
what do the positions on pacing indicate?
position 1 - chamber paced
position 2 - chamber sensed
position 3 - mode of response
position 4 - programmable functions
position 5 - anti tachy mode
107
what is the difference between a thermistor and thermocouple?
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.
108
what metals are typically used in a thermocouple?
copper and constantan
two dissimilar metals
seebeck
109
which anti HTN med on ITU is a red / brown powder? what is the toxcity effect of this?
sodium nitroprusside
produces nitric oxide, cyanide ions and methaemoglobin
110
what type of giving set should be used with sodium nitroprusside?
opaque
degrades in sunlight
111
what is a rare haematological side effect of gold?
pancytopenia
112
what is the order of toxicity based on location for local anaesthetic agents?
in order or descending incidence:
Intercostal space > caudal > epidural > brachial plexus > femoral > subcutaneous.
113
what are the different sizes for BP cuffs?
Appropriate sizes are:
3cm – infant.
6cm – child.
9cm – small adult.
12cm – adult.
15cm – large adult.
114
what do the following degrees of current do to a patient if accidently exposed
1mA, 5mA, 15mA, 30mA, 50mA, 100mA, 1000mA
1 = tingling
5 = pain
15 = severe pain and muscle contraction
30 = cant let go
50 = asphyxia (resp muscle contraction)
100 = VF
1000 = burning
115
what structures pass the superior orbital fissure?
lacrimal nerve
frontal nerve
trochlea nerve
occular motor nerve
abducens nerve
nasociliary nerve
opthalmic vein
116
how is rocuronium mainly excreted?
bile
117
what class of muscle relaxant is rocuronium?
monoquarternary aminosteroid
118
in a system how can natural resonance relate to different properties e.g. of arterial pressure system?
NF ∝ d/√(cρl) where d = diameter, c = compliance, l = length and ρ = density.
119
how does class Ia, b, c anti-arrhythmics effect refractory period?
1a = increase
1b = decrease
1c = no effect
120
what factors affect the likelihood of hard with current to the body?
most important factor = frequency.
unfortunately mains frequency of 50Hz is most damaging
amplitude of current
duration of current
121
what can hydralazine precipitate?
SLE
122
what can happen when sodium nitroprusside is stoped?
rebound HTN
123
what can you say about metabolism of hydralazine?
polymorphisms
variable clearance due to 50% being slow acetylators
124
how can you classify the Manley MP3?
pressure generated
time cycled
minute volume divider
125
how does a left sided double lumen ET tube work?
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
126
why is a transformer used in a debib circuit?
step up from 240V to 5000V
127
describe how Class I, II, III equiptment safety is categorised?
class I - earthing
class II - extra insulation, no earth
class III - extra low voltage
128
what is class B, BF and CF equiptment?
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
129
which antibiotic can give serotonin syndrome?
linezolid
130
what are the side effects of MAOI?
psychosis
weight gain
orthostatic hypotension
serotonin syndrome (if used with other serotonergic agents)
hypertensive crisis if certain tyramine rich foods are consumed.
131
what are the 5 methods of filtration by filters used in breathing systems?
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 –
132
how is a canula sterilised prior to use?
it is packaged so cant undergo autoclave
it is sterilised via ionising radiation
133
how is majority of atracurium metabolised?
60% ester hydrolysis
30% hoffman
10% unchanged
134
how does acidosis affect hoffman?
slowed by acidosis and cold
135
what common drug cant be given with clopidogrel and why?
omeprazole
inhibits CYP 2C19 - cant convert clopi to active form - less effect
136
which is the anti emetic of choice in parkinsons?
Domperidone
137
how much CO2 can be absorbed by 500g of soda lime?
125L
138
what factor doesnt affect the accuracy of pneumatograph
resistance of the device
139
what does the SAGM solution consist of and why?
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
140
RBC can be stored in citrate -dextrose - what is this solution good for?
citrate binds calcium and acts as an anticoagulant
dextrose acts as a RBC substrate
141
how long can RBC survive with citrate phosphate dextrose vs citrate dextrose?
citrate -dex = 21 days
with phorphate = 28 days
above with adenine = 35days
142
what is the advantage of citrate-adenine-phsophate dextrose as a RBC solution for storage?
adenine is able to increase RBC ATP and hence survival to 35 days
143
how much more potent is alfentanil than morphine?
10x more
144
what is the Vd of alfentanil?
0.6L/Kg
145
what is the frequency of ECG in diagnostic and monitoring mode?
0.05-100/150Hz = diagnostic
0.5-40Hz = monitoring
146
which agent produces compound A?
sevo
147
which inhalation agent DOESNT produce CO?
SEvo
iso, enflurane and des all do
148
mechanism for morphine tolerance?
uncoupling of G protein from GPCR seems to predominate as the cause
149
how is the Ga subunit of a GPCR turned off?
Ga has GTPase activity which will catalyse the GTP to GDP to limit the reaction and deactivate/ turn off signally.
150
what is a kinase and phosphatase?
kinase - adds P = phosphorylases a substance
phosphatase = removes P
151
2 ways to size a guedel?
Either distance from midpoint of incisors to angle of mandible, or distance from the corner of the mouth to the tragus.
152
what nerves are blocked by a transversus abdominis plane block?
TAP block
ilioinguinal
iliohypogastric
subcostal
153
what is the mechanism of halothane hepatitis?
trifluroacetyl metabolities bind liver proteins --> autoantibodies
leads to centrolobular necrosis
154
how is weight estimated from age of a child?
age + 4
multipled by 2
155
what is the size of an LMA based on weight?
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
symptoms of high lithium?
COURSE tremor
N&V
ataxia
loss of conscioussness
seizures
nystagmus
hyperreflexia
157
what mechanism of a filter will filter viruses?
viruses are small 0.1um
rely on brownian diffuison (<0.5um)
158
what are the methods of which a filter can filter particles?
gravitational settling >5um
inertial impaction - 0.5 to 1um
interception - 1um
brownian diffusion <0.5um
electrostatic interaction
159
define magnetic flux?
measurement of total magnetic field passing through a given area
160
at what point is the absorption specta of carboxyHb similar to other Hb?
similar to oxy Hb at 660
(this doesnt mean oxy Hb has greatest absorption at 660 - deoxy still does)
161
how much bile produced each day? can it undergo 1st pass metabolism?
600ml
yes reabsorbed at terminal ileum (90%) as secondary bile acids (bacteria modify hydroxyl groups). then undergo 1st pas metabolism
162
what is the dose of phenytoin in kids?
20mg/kg
over 20 mins
ecg monitoring
163
what is dose of levetiracetam in kids?
30-60mg/kg - max 3g
164
causes of raised anion gap?
10-20 is normal - mudpiles
methanol
uraemia
DKA
Propylene glycol
Iron, isoniazod
lactate
ethanol, ethylene glycol
salicylates
165
what happens with halothane and rubber?
halothane is absorbed into rubber.
if this is present in the circuit, it can reduce amount delivered to patient.
166
where does the anterior scalene attach to 1st rib?
anterior scalene attaches to scalene tubercle of 1st rib
167
how is sux apnoea inherited?
recessive
chrom 3
168
what is prefered for a fascia iliaca block - low or high vol?
high volume block
169
name 2 primary and 2 secondary bile acids...
primary = cholic acid and chenodeoxycholic acid
secondary = lithocholic acid and deoxycholic acid.
170
what is the pathophysiology of heparin induced thrombocytopenia?
IgG antibodies to platelet factor 4 / heparin complex
leads to thrombus formation and destruction of platelets
170
where in the airway do particles get filtered depending on size?
upper airway = 40um
bronchi = 8-15um
peripheral conducting airway 3-5um
alveoli = 0.8-3um
170
what are the 4 Ts to estimate likelihood that a fall in platelet count is caused by heparin induced thrombocytopenia?
timing
magnitude of platelet drop
thrombosis or other sequale
potential for other causes of thrombocytopenia
171
what is the minimum efficiency size of a filter (that filters particles)?
0.3um
172
what is the purpose of the selectatec interlock system on the vapouriser?
ensures only one vaporiser can be fitted at a time
173
what tracheostomy should not be used in patients with high aspiration risk?
a fenestrated tube should be avoided
174
what tracheostomy tube is safest to use in those cared for out of tracheostomy specialised areas?
uncuffed - prevents risk of cuff herniation.
175
what type of tracheostomy should be used if invasive ventilation is to continue
cuffed tube
176
how do antifungals work?
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
cat 1 C section for fetal brady, Cant intubate, get i gel in. what next?
continue with C section with cricoid on
178
how much csf proced each day?
450ml
(150 ml present at one time)
179
what is the response time of a thermistor like? how sensitive is it?
slow
very sensitive
fragile
180
what are the advantages and disadvantages of a side stream gas analyser?
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
what are the pros/cons of mainstream sampling gas analysis?
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
what are the side effects of cimetidine?
CYP450 inhibitor
anti-androgen effects - impotence, gynacomastia and reduced sperm count.
183
where does the larynx sit in children vs adults?
adults = C3 to C6
children = C2/C3
184
what happens if you cant pass a suction catheter down a trachea and patient not ventilating?
deflate the cuff - they can potentially orally oxygenate
185
which is the only agent increasing cerebral blood flow?
ketamine
(and hence increase in ICP)
186
what electrolyte changes are seen in furosemide?
low, K, Mg, Ca
Can cause hypernatraemia
187
what is engraved on cylinders?
date of test
test pressure
chemical formula of gas
tare weight
188
what does the shape and colour of the plastic disc on the neck of a cylinder indicate?
year of inspection
189
what are U1 and U2 opioid receptors responsible for?
U1 = analgesia and dependance
U2 = resp depression, reduced peristalsis, miosis and euphoria
190
what are the 3 phases of gastric acid secretion?
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
what inhibits gastrin release?
secretin = released from S cells in duodenem due to acidity
somatostatin = released by D cells of stomach when pH <2
192
what is the equation for length of tube in children?
age / 2 +12
193
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
treatment group:
2 people diseased, 10 people without = 2/10
non treatemtn
5/10
overall odds ratio 0.2/0.5 =0.4
194
what is the pressure of:
- piped O2 /N20/ Air
- cylinders of O2 and entanox
- cylinder of N20
- air for driving tools in pipeline
- 4 bar
- 137 bar
- 52 bar (at 20 degrees), 44 bar at 15 degrees.
- 7 bar
195
what is the max leakage current for CF devices?
single fault = 50uA
multiple = 10uA
196
which esterases are the following drugs metabolised by? aspirin, esmolol, sux/mivacurium, remi, local anaesthetics
asprin = hepatic and intestinal esterases
mivacurium/sux / Local A= plasma cholinesterases
remifentanil - non specific plasma / tissue
esmolol = red cell esterases
197
how is relative risk reduction calculated?
calculate % in each group
find difference = absolute risk reduction
divide difference by control group %
198
what is included in turbulent flow equation?
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
name some different phosphodiesterase inhibitors?
milronone, enoximone = selective for PDE III
sildenafil and dipyramidol = PDE V
aminophylline/ theophylline = non selective
200
how much more lipid soluble and potent is fent than morphine?
x100 more potent
x600 more soluble
201
what is the narrowest part of the airway in children?
level of crircoid cartilage
adults = laryngeal inlet.
202
how does basal oxygen consumption and MV compare in children to adults?
increased basal O2 consumption
increased MV (100ml/kg/min in children, 60ml/kg/ min adults)
203
how does an intra-aortic balloon pump work?
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
for aortic doppler. how is the flow time corrected calculated?
if this is low/high what does it suggest?
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
what does vit B12 bind to in plasma?
Transcobalamins
206
what does haemopexin bind to in plasma?
free haem
207
what is a cardiff aldasorber?
passive scavenger
for anaesthetic agents
(not CO2 or N20)
208
what amp output does nerve stimulator use in nerve blocks?
initially 1-3mA
as it gets constractions, reduce output
if 0.3-0.5 it is very close
<0.2mA = intraneural
209
what is the mechanism of nicrorandil?
ATP sensitive pottasium channel activator - hyperpolarisation and relaxation of arteriole.
210
what was the issue with Tec 2 method of temp compensation?
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
what happens to lung volumes in pregnancy?
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
what is the breakdown product of noradrenaline?
VMA
by comt and Moa
213
how is noradrenaline formed?
from dopamine
via dopamine hydroxylase
214
what chains make up fetal Hb?
2 alpha
2 gamma
215
what is HbA1 and HbA2?
HbA1 = 98% of adult Hb = 2 alpha and 2 beta
HbA2 = 2% of adult Hb = 2 a and 2 delta
216
what is the max absolute humidity at 37 degrees?
44 g/m3
217
what is the efficiency of a HME filter? what humidity can it achieve at 37 degrees?
at 37 degrees = max absolute =44g/m3
efficiency of HME = 60-70%
hence humidity = 26-30g/m3
218
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?
VD/VT = (PaCO2 - PECO2)/ PaCO2
difference between 1/5th
1/5th of VT = 100ml
219
how does trimetaphan work?
blocks nAChR
reduces BP by acting centrally and blocking ganglionic transmission.
220
how does methyl dopa work?
stimulates alpha 2 receptors
221
name 4 drugs causing gynaecomastia..
spironolactone
digoxin
isoniazid
cimetidine
222
how long is the cardiac action potential?
300ms
223
what is the role of the pilot balloon on ET tube?
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
what should ET tube cuff pressure be?
low pressure high vol
20-30cmH20
225
what important DDI does linezolid have?
acts as a weak non selective MAO inhibitor
hence can precipitate HTN crisis/ serotonin syndrome
226
what is the action of levosimendan?
calcium sensitizer in cardiac muscle
sensitiser cardiac muscle fibres to calcium and increases contractility without increase in O2 consumption.
227
which local anaesthetic can cause methamoglobinaemia?
prilocaine
due to o toludine metabolite
228
which needles can be used in spinal and why?
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
what is the Dibucaine test?
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
what are the borders of the cubital fossa?
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
what is the absolute humidity at 20 degrees?
17 g/m3
232
how much adrenaline in anaphylaxis by age?
0-6month = 100mcg
6 months - 6yrs =150mcg
6yrs -12 yrs = 300mcg
12 yrs + = 500mcg
IM 1:1000 e.g. 0.1ml = 100mcg
233
what is the dose of adrenaline in an arrest in paeds?
10 mcg/kg
e.g. 0.1ml /kg of 1:10000
234
state the cyp450 inducers and inhibitors...
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
what are the guidelines for HTN at elective surgery?
proceed if <160/100mmHg in primary care
on day of surgery acceptable to be up to 180/110
236
how long is autoclaving performed for?
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
what is the mechanism behind cardio and neurotoxicity in TCA overdose?
their interaction with VG Na channels
238
how is protein binding in TCA overdose increased?
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
what is the induction dose for etomidate?
0.3mg/kg
240
which roots and cord does the ulnar nerve come from?
C8 to T1
medial cord
241
what is the sural nerve?
formed from both the common peroneal and tibial nerves,
purely sensory
to the posterolateral leg and the lateral aspect of the foot.
242
what is sucralfate?
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
how does nitrous oxide lead to problems chronicaly
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
pathway for NA and adrneline production...
tyrosine --> LDOPA (tyrosine hydroxylase)
LDOPA --> dopamine (L DOPA decarboxylase)
dopamine --> NA (dopamine hydroxylase)
NA --> adrenaline (PNMT)
245
what is the difference between giving dopamine at low and high doses?
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
what % does renal blood flow increase in pregnancy?
50%
247
which hormone has ADH like activity?
oxytocin
248
what is the half life of ADH?
5 mins
249
which enzyme converts NA to adrenaline
PNMT (phenylethanolamine N-methyltransferase)
250
what would
- tricuspid stenosis
- tricuspid regurg
- complete HB
show on JVP?
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
name drugs used for SVT, VT and both
Supraventricular only: digoxin, verapamil, adenosine.
Ventricular only: lidocaine, phenytoin.
Both: amiodarone, beta-blockers, disopyramide, procainamide, fleicanide.
252
name 2 B2 agonsits
salbutamol
terbutaline
can give either in asthma
253
contraindications to epidural spinal?
patient refuses
infection at the site or sepsis
hypovolaemia - severe
aortic stenosis / HOCM
increased ICP
coagulopathy
254
how should methadone be managed perioperatively?
continue
255
what are the contraindications to an aortic balloon pump?
severe aortic regurgitation
Aortic dissection
sepsis
severe peripheral vascular disease.
used post cardiac surgery to support failing heart whilst awaiting definitive management
256
name agents to
- estimate total body water
- ECF
- plasma
- red cell volume
Deuterium oxide – Total body water
Inulin – Extracellular fluid
Plasma – Radiolabelled albumin, Evan’s blue
Red cell volume – Radiolabelled red cells
257
colour coding of inhaled anaesthetic agents...
Red – halothane
Purple – isoflurane
Yellow – sevoflurane
Blue – desflurane
Orange – enflurane
258
state the respiratory quoient for different diets?
fat is 0.7, for protein 0.8, and for carbohydrate 1.0.
259
how does GABAPENTIN work?
blocks L type Ca channels
also modulates GAD which increases levels of GABA
260
what is oral bioavailability of tramadol like?
90%
similar IV and oral dose
261
does tramadol have isomers
yes exists as racemic mixture
262
explain the pathway for adrenaline and norad production
tyrosine --> L dopa (tyrosine hydroxylase)
L dopa --> dopamine (dopa carboxylase)
dopamine --> NA (dopamine hydroxylase)
NA --> adrenaline (PNMT)
263
how is TPN calculated?
30-40ml/kg / day = fluid
30kcal/kg/day - medical
45 cal/kg/day - post op
protein - 1kg/day post op
264
what does pregnancy do to MAC?
decreases it
265
where do osmotic diuretics work?
loop of henle (and PCT)
e.g. mannitol
266
where does amiloride work?
DCT
267
describe management of diabetes for surgery where there is no more than 1 missed meal?
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
safe dose of prilocaine?
6mg/kg
269
what actions does amitriptlyine have?
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
how is numbers needed to treat calculated?
The number needed to treat is 1/ARR
ARR = incidence in control group – incidence in treatment group
e.g. % -%
271
which is quicker capnography or pulse oximetry?
capnography - delay of around 3 seconds
pulse ox = 20sec
272
is gluconeogesis aerobic or anaerobic?
anaerobic
273
what happens to flow in variable intrathoracic obstruction? extrathoracic?
intrathoracic = inspiratory flow preserved
extrathoracic = expiratory flow normal , insp reduced
Fixed large airway obstruction has reduced flow in both inspiration and expiration.
274
what is larger peak exp or peak insp?
In health, the peak expiratory flow rate exceeds that of inspiration.
275
what is the function of fusidic acid?
inhibits protein synthesis - ribosomal function.
276
how does B2 result in bronchial smooth muscle relaxation?
Gs, cAMP, PKA, MLCkinase inactivation ! also indirectly activates MLCphosphatase
277
what are the advantages of biphasic defib?
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
positions on pacemaker....
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
what rate does a wrights respirometer rotate? which part of breathing circuit is it positioned?
150 revolutions per litre of gas flow
expiratory limb
280
how will wrights respirometer work at low TV?
under estimate due to friction
281
what can suggamadex be used for?
roc
vec
(more effective with roc)
282
which diuretics work in Distal convoluted tubule?
Early distal convoluted tubule: thiazide diuretics.
Distal convoluted tubule: amiloride
283
which structures do the roots of the brachial plexus pass when exiting the neck?
what structures do they run with after this?
anterior and middle scalene muscles
then run in close proximity to subclavian artery
284
how long does a battery pacemaker typically last?
8-10 yrs
285
what is this...
halothane
Mr = 197
286
what does hamburger shift describe?
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
what is the respiratory exchange ratio?
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
what is the ideal blood pressure cuff size?
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
what is special about GTN infusions during set up of the infusion?
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
which infusion should you avoid sunlight with?
sodium nitroprusside
need to wrap giving sets in tinfoil
otherwise liberation of cyanide ions
291
what do you dilute sodium nitroprusside in?
5% dextrose
292
what can increase damping within arterial blood pressure system?
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
is halothane hepatitis more common in adults or children?
adults
risk factors
obesity, female sex, pre-existing liver disease and repeated exposure to halothane.
294
how is O2 content calculated?
(1.34 x Hb x SpO2) + (0.0225 x PaO2)
0.003 for mmHg
295
what is larmor frequency?
rate of precession of a magnetic moment
depends on magnetic field stretnght and the gyromagnetic ratio
296
how is type 1 basal bolus insulin managed for surgery?
missing 1 meal = give normal basal insulin, omit morning and lunchtime short acting
missing 2 meals = VRII
297
colours of filters on breathing machines...
yellow – breathing filters microbes
Blue – heat and moisture exchange.
Green – both
298
which antibiotic causes peripheral neuropathy?
nitrofurantoin & metronidazole & ciprofloxacin
irreversible
299
mechanism of
dipyramidole
tirafiban
clopidogrel
dipyramidole - phosphodiesterase
Clopidogrel - ADP (P2Y12 receptor)
tirafiban - GPIIb/IIIa
300
how is pulmonary vascular resistance calculated?
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
define mixture...
2 or more substances dispersed through one another whose consituent parts retain their original identity
302
define solution
solvent and solute combine to make a new homogenous substance. not a mixture
303
define suspension
A suspension is two or more substances mixed together where the heavier substance will eventually settle out under gravity.
304
define colloid
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
define emulsion
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
what is the normal systemic vascular resistance value?
800-1600 dyn.s.cm-5
307
in pregnancy what is main cause of increased CO?
Stroke volume (due to preload)
also some increase in HR (25%) but mostly SV (30%)
308
what is the advantage of the miller blade?
straight blade
used in paeds to lift epiglottis out the way
309
what % receptors occupied per ToF count?
0 twitches = 95-100%
1 twitch = 90%
2 twitch = 80%
3 twitches = 70%
all twiches <70%
310
what is function of long inlet port on the vapouriser?
prevent bypass channel becoming contaminated with retrograde flow
311
why are equal volumes used in bypass channel and vapourising chamber?
ensure any gas expansion is equal .
312
how do saline filled lungs change compliance?
reduces surface tension hence increases compliance
313
how do basal alveoli and apical alveoli compare on compliance curve?
Basal alveoli are less distended at rest than apical alveoli, and so are on a steeper part of the compliance curve.
314
define sterilisation
The process of rendering an object free from all pathogenic organisms including bacterial spores
315
define disinfection...
Disinfection: The process of rendering an object free from all pathogenic organisms except bacterial spores
316
which organelle is highly present in Z3 of liver?
Smooth endoplasmic
for drug metabolism.
317
what is the hepatic artery a branch of?
coeliac trunk
318
what wavelength do different lasers use?
argon = 400-600nm - blue/green - opthalmic surgery
NAD-YAG - 1060nm - endoscopic and oesophageal varices
CO2 - 10600nm - poor tissue penetration, superficial airway surgery
319
what is the atm pressure at 5500 meters?
50 kpa
roughly 0.5atm
320
what is a notch filter and bandwidth filter?
notch filter = removes specific wavelength
bandwidth = allows through band of wavelegnth
321
what current is delivered in PTC?
50Hz 5 seconds
followed by 3 second pause
1 hz x 20 stimuli
322
which electrodes are seen in pH measurements ?
reference electrode = mercury / calomel (or Ag/AgCl) + KCL
measuring = Ag/Agcl, buffer solution
323
what is meant by population inversion in LASER?
state where lasting medium where more atoms are high energy state than ground energy state
324
what does a sieving coefficient of 1 mean?
freely filters across and equilbriates with plasma e.g. glucose
325
what is iloprost used for?
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
name 3 types of meds used in pulmonary artery HTN
endothelin antagonists = bosentan, ambrisentan
prostacyclin agonist = iloprost, epoprostenol
PDE5 inhibitors = sildenafil
327
what is a supramaximal stimulus?
A supramaximal stimulus is typically 25-50% higher than that needed to produce a maximal response.
328
why is having an increased horizontal width beneficial of an i gel?
prevents rotation
329
which nerves are blocked in an axillary nerve block?
ulnar, radial, median, musculocutaneous
the musculocutaneous lies away from the other 3 and needs redirection of needle for local injection
330
how does erythromycin work as a prokinetic?
mimics motilin
agonist at motilin receptors
331
which conditions lead to inaccuracies of wedge pressure estimating LA pressure
mitral stenosis/ regurgitation
atrial myxoma
pulmonary veno occlusive disease
cardiac tamponade
332
state the laws of thermodynamics?
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
how does Calcium conc compare in CSF to plasma?
lower in CSF
334
how does Mg compare in CSF to plasma
higher in CSF
335
name phase 1 reactions in liver
by CYP450
oxidation, reduction, hydrolyiss
dealkylation and deamination
336
how does rate of elimination compare to clearance?
rate of elim = clearance x plasma conc
337
what do I cells of stomach secrete?
Cholecystokinin
338
why does renin rise in HF with low ejection fraction?
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
what should stroke volume variation % be to be fluid responsible
if <10% unlikely fluid responsive
340
how do lisinopril and enalapril vary in metabolism?
enalapril - prodrug, metabolised by liver
lisinopril not metabolised, excreted unchanged
341
How does pethidine solubility and potency compare to morphine?
relative lipid solubility x 30 t
relative potency x 0.1 that of morphine.
342
how does ephedrine work?
Within the neuron, ephedrine exchanges with noradrenaline via VMAT
causes release noradrenaline into the synaptic cleft, which stimulates α1 adrenoreceptors leading to vasoconstriction
343
target CO2 in head injury?
4.5-5 kPa.
344
what is the effect of bicarb on local anaesthetics?
sometimes added to increase unionised form
345
what is more potent lidocaine or bupivacaine?
bupivacaine
346
compare lipid solubility of fentanyl and alfent?
fent = 600x morphine
alfent = 90x morphine
347
what is more potent alfent or fent?
fentanyl
348
what is purpose of bodok seal?
It is found on the anaesthetic machine between the valve block and the yoke in order to prevent gas leak.
349
mechanism of ciprofloxacin?
fluroquinolone
DNA gyrase/ topoisomerase inhibition - DNA synthesis inhibition
350
mechanism of rifampicin
RNA polymerase inhibition
351
mechanism of aminoglycosides? example drug?
gentamicin
30S inhibition
352
erythromycin class?mechanism
macrolide
50S inhibition
353
cannula flow rates...
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
what koratkoff does diastolic and systolic correspond to?
In the UK, systolic blood pressure corresponds to phase I, diastolic blood pressure to phase IV (phase V in the US).
355
what is Aliskiren?
direct renin inhibitor
prevents angiotensinogen to angiotensin 1
356
equation for loading dose...
Loading dose (mg) = concentration (mg/ml) x volume of distribution (ml)
357
what is T1 and T2 relaxation in MRI?
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
safety features of Tec 6?
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
what blade is the wisconsin blade similar to? when can it be used?
Miller
straight blader
used in paeds for getting epiglottis out the way
360
mechanism of labetalol?
non specific alpha and beta antagonist.
361
what size mesh do epidural filters have?
0.22 microns
362
what is the newton valve?
valve used in penlon nuffield so it can be used in paeds by preventing volutrauma.
363
how can an elastomeric pump be turned into a PCA?
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
what is the shunt equation?
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
mechanism of action of glibenclamide?
sulphonylurea
366
colours for venturi for % O2
blue = 24%
white = 28%
orange = 31%
yellow = 35%
red= 40%
green = 60%
367
Difference between Oxford min and Goldman
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
How many vaporisers in tri service ap?
2x Oxford min
369
What is more potent morphine or it’s metabolites ?
Morphine 6 glucuronide x13 more potent
370
Order of amount of co2 carried by differnt components in blood
Bicarbonate 60%
Carbamino 30%
Dissolved 10%
In arterial blood more is carried by bicarb and less by carbamino due to haldane effect
