Teach me bank Flashcards
how is volume of local anaesthetic in a obstetric spinal compare to normal?
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.
what level of block is required for a C section?
block to T4-T5
what factors influence the efficiency of HME?
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.
what is Edrophonium?
short acting acetylcholinesterase inhibitor
can temporarily relieve myasthenia symptoms
what are the subunits in a nictotinic Ach receptor?
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.
when can acetazolamide be used?
altitude sickness
glaucoma
metabolic alkalosis
write the equation for wash in curve…
y = a(1-e-kt).
sometimes as
A - Be-kt = just multiplied out of brackets
what is the mechanism of action of milronone?
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)
how does cAMP rise in smooth muscles result in vasodilation?
cAMP –> PKA –> phos of L type Ca channels –> reduced entry of Ca
also phosphorlyates pumps and proteins to increase efflux of Ca
how much suggamadex is given in different situations?
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
how is MAC affected by pregnancy?
reduced
what type of tilt is recommended in preg to relieve aortovenal compression
left lateral
why can oxytocin only be given after delivery of term baby?
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.
how does propofol cause hypotension?
Propofol impairs central vasomotor control and has peripheral effects on inhibition of L-type calcium channels.
what is the cori cycle?
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
what is the order of highest to lowest MAC? i.e. least to most potent
Nitrous oxide – Xenon – Desflurane – Sevoflurane – Enflurane – Isoflurane – Halothane.
‘no X delicious Sex equals incredible happiness’
what is the bohr equation?
Vd / Vt = (PaCO2 – PeCO2)/PaCO2,
where Pa and Pe are the arterial and expired partial pressures of carbon dioxide
what does an undersized cuff do to BP readings?
overestimate
of systolic AND diastolic
which ant acid causes diarrhoea?
magnesium trisilicate
(Aluminium containing antacid medications also tend to cause constipation rather than diarrhoea)
which antiepileptics are Na channel blockers
Phenytoin, carbamazepine and lamotrigine.
what is the action of ethosuximide
Calcium current inhibitors
what contributes to phase 4 of cardiac pacemaker cells?
funny current sodium channels and T-type calcium channels
what is the max dose of ramipril?
10mg
what should BP in community be before elective surgery?
<160/100mmHg
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.
what type of current is delivered by TOF?
50mA
2Hz - 1 stimulus every 0.5 seconds
4 in total
each lasts 0.2ms
how does a pressure / volume loop look for aortic stenosis?
thinner and narrower
same end systolic volume , reduced SV hence increase in EDV
which metabolite of morphine is active?
morphine 6 glucuronide
what structure passes through foramen spinosum?
middle meningeal artery
which structure passes through the foramen rotundum?
maxillary nerve
what structure passes through the optic canal?
opthalmic artery
optic nerve
which structure passes through the foramen ovale ?
mandibular nerve
which Abx caused most anaphylaxis according to NAP 6?
Teicoplanin and then co amox
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.
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.
how do opioids exert action on receptor?
stimulation of Gi
hyperpolarisation
via K+ efflux
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.
which GI medication can increase warfarin effects?
cimetidine = H2 antagonist
used for reflux
inhibits CYP450
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.
in a dose response curve, which axis is logarithmic?
x axis - log dose
y axis - response % of max response
how is relative risk calculated?
note not relative risk reduction.
relative risk = % in new drug / % incidence in old drug
what is the absolute pressure of a cylinder?
gauge + atm
e.g. 13700 + 101
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.
for LA what determines speed of onset, potency and long lasting?
pka = speed
lipid solubility = potency
PB = lasting effects
what is the critical pressure of nitrous oxide?
72 bar
what is the volume of CSF in healthy adult?
150ml
Around 500ml produced per day
what is the urea cycle?
conversion of ammonia to urea
occurs in hepatocytes - between mitochondria and cytosol
urea can then be excreted
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.
how do B agonists and aminophylline interact?
synergistically
what is the root mean square deviation. ?
same as Standard deviation (different name)
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
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
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.
what class of drug is tolbutamide
sulphonylurea
how much CSF is produced each day in health?
450 ml
(3x normal volume = normal vol is 150ml)
in cant intubate, cant oxygenate, what is recommended?
cricothyroidotomy
NOT Tracheostomy
when may a mainsteam analyser be used for gas analysis?
neonate - less deadspace, more accurate for smaller volumes
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
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.
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.
how is rivaroxaban immediately reversed?
andexanet alpha
OR
prothrombin complex concentrate (Beriplex, 50 units/kg)
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
in fetal circulation, which structure is important in ensuring oxygenated blood goes preferentially to the brain?
Eustachian valve
how many drops of fluid and blood is equivalent to a ml?
20 drops = 1 ml of fluid
15 drops = 1 ml of blood
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
what type of chemical are all 4 induction agents?
ketamine = phencyclidine
propofol = phenol
thiopentone = barbiturate
etomidate = imidazole (has an ester link)
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
what are the pka values of induction agents?
propofol = 11
etomidate = 4
thio = 7.6
ketamine = 7.5
of the IV induction agents which has smallest Vd?
largest propofol = 4mg/lg
smallest thio = 2.5mg/kg
ket and etomidate = 3mg/kg
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
what is the mechanism of tirafiban?
glycoprotein IIb / IIIa antagonist - antiplatelet
blocks platelet aggregation
give examples of ADP receptor blockers…
clopidogrel
prasugrel
ticagrelor
inhibit platelet activation
which antibiotics can worsen weakness in myasthenia gravis?
aminoglycocides - gentamicin, streptomycin
macrolides - clarithromycin, azithromycin etc
fluroquinolones - ciprofloxacin
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)
what is the formula for cuff size of ET tube in children?
age / 4 + 4
what parts of spinothalamic tract carry what sensations?
lateral = temperature + pain
anterior = crude touch and pressure
(dorsal = light touch, vibreation , proprioception)
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.
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
what is the primary intracellular buffer?
phosphate
what is the urinary buffer?
phosphate
ammonium
bicarb
what are the cathodes and anodes of a galvanic fuel cell?
LAG = lead anode, gold cathode
what can Piezoelectric quartz crystal oscillation be used for?
volatile anaesthetic measurement
which vessels does GTN act on?
low dose - veins / capacitance vessels - decreased preload , compensatory tachycardia
high dose - arteriolar dilation - reduced afterload
what is damping coefficient for optimal damping?
0.64
whats the ratio of adrenaline/NA release by adrenals?
80:20
more adrenaline
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)
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.
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
what is pralidoxime?
antidote for organophosphate poisoning
in pressure swin adsorption for concentrating oxygen what chemical is used to remove the nitrogen
Zeolite = aluminium and silica crystals
what does a wrights respirometer measure?
expiratory volumes
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
which dural sinus does the IJV originate from?
sigmoid sinus
exits via jugular foramen
what is protein binding of digoxin and amiodarone like?
high - one can displace the other leading to toxicity
why are children more prone to bradycardia in theatre?
increased parasympathetic tone
more affected by vagal stimulation
what is the mechanism of cangrelor? how is it given
reversible ADP inhibitor
given IV
rapid onset and quick recovery
what is the safe occupational exposure of halothane?
10ppm
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
what is the Vd of ketamine?
3L/kg
what is the half life of amiodarone?
long
up to 100days
what is the dose of amiodarone?
loading = 300mg over 1 hour
then = 900mg over 24 hrs
what is the typical value of pulmonary capillary wedge pressure?
6-12 mmHg
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
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.
how is pulmonary vasc resistance measured?
PVR = 80 x (Mean pulmonary artery pressure - LA pressure)/ CO
units dyne.s-1.cm-5
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
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.
what metals are typically used in a thermocouple?
copper and constantan
two dissimilar metals
seebeck
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
what type of giving set should be used with sodium nitroprusside?
opaque
degrades in sunlight
what is a rare haematological side effect of gold?
pancytopenia
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.
what are the different sizes for BP cuffs?
Appropriate sizes are:
3cm – infant.
6cm – child.
9cm – small adult.
12cm – adult.
15cm – large adult.
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
what structures pass the superior orbital fissure?
lacrimal nerve
frontal nerve
trochlea nerve
occular motor nerve
abducens nerve
nasociliary nerve
opthalmic vein
how is rocuronium mainly excreted?
bile
what class of muscle relaxant is rocuronium?
monoquarternary aminosteroid
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.
how does class Ia, b, c anti-arrhythmics effect refractory period?
1a = increase
1b = decrease
1c = no effect
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
what can hydralazine precipitate?
SLE
what can happen when sodium nitroprusside is stoped?
rebound HTN
what can you say about metabolism of hydralazine?
polymorphisms
variable clearance due to 50% being slow acetylators
how can you classify the Manley MP3?
pressure generated
time cycled
minute volume divider
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
why is a transformer used in a debib circuit?
step up from 240V to 5000V
describe how Class I, II, III equiptment safety is categorised?
class I - earthing
class II - extra insulation, no earth
class III - extra low voltage
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
which antibiotic can give serotonin syndrome?
linezolid
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.
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 –
how is a canula sterilised prior to use?
it is packaged so cant undergo autoclave
it is sterilised via ionising radiation
how is majority of atracurium metabolised?
60% ester hydrolysis
30% hoffman
10% unchanged
how does acidosis affect hoffman?
slowed by acidosis and cold
what common drug cant be given with clopidogrel and why?
omeprazole
inhibits CYP 2C19 - cant convert clopi to active form - less effect
which is the anti emetic of choice in parkinsons?
Domperidone
how much CO2 can be absorbed by 500g of soda lime?
125L
what factor doesnt affect the accuracy of pneumatograph
resistance of the device
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
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
how long can RBC survive with citrate phosphate dextrose vs citrate dextrose?
citrate -dex = 21 days
with phorphate = 28 days
above with adenine = 35days
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
how much more potent is alfentanil than morphine?
10x more
what is the Vd of alfentanil?
0.6L/Kg
what is the frequency of ECG in diagnostic and monitoring mode?
0.05-100/150Hz = diagnostic
0.5-40Hz = monitoring
which agent produces compound A?
sevo
which inhalation agent DOESNT produce CO?
SEvo
iso, enflurane and des all do
mechanism for morphine tolerance?
uncoupling of G protein from GPCR seems to predominate as the cause
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.
what is a kinase and phosphatase?
kinase - adds P = phosphorylases a substance
phosphatase = removes P
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.
what nerves are blocked by a transversus abdominis plane block?
TAP block
ilioinguinal
iliohypogastric
subcostal
what is the mechanism of halothane hepatitis?
trifluroacetyl metabolities bind liver proteins –> autoantibodies
leads to centrolobular necrosis
how is weight estimated from age of a child?
age + 4
multipled by 2
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)
symptoms of high lithium?
COURSE tremor
N&V
ataxia
loss of conscioussness
seizures
nystagmus
hyperreflexia
what mechanism of a filter will filter viruses?
viruses are small 0.1um
rely on brownian diffuison (<0.5um)
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
define magnetic flux?
measurement of total magnetic field passing through a given area
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)
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
what is the dose of phenytoin in kids?
20mg/kg
over 20 mins
ecg monitoring
what is dose of levetiracetam in kids?
30-60mg/kg - max 3g
causes of raised anion gap?
10-20 is normal - mudpiles
methanol
uraemia
DKA
Propylene glycol
Iron, isoniazod
lactate
ethanol, ethylene glycol
salicylates
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.
where does the anterior scalene attach to 1st rib?
anterior scalene attaches to scalene tubercle of 1st rib
how is sux apnoea inherited?
recessive
chrom 3
what is prefered for a fascia iliaca block - low or high vol?
high volume block
name 2 primary and 2 secondary bile acids…
primary = cholic acid and chenodeoxycholic acid
secondary = lithocholic acid and deoxycholic acid.
what is the pathophysiology of heparin induced thrombocytopenia?
IgG antibodies to platelet factor 4 / heparin complex
leads to thrombus formation and destruction of platelets
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
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
what is the minimum efficiency size of a filter (that filters particles)?
0.3um
what is the purpose of the selectatec interlock system on the vapouriser?
ensures only one vaporiser can be fitted at a time
what tracheostomy should not be used in patients with high aspiration risk?
a fenestrated tube should be avoided
what tracheostomy tube is safest to use in those cared for out of tracheostomy specialised areas?
uncuffed - prevents risk of cuff herniation.
what type of tracheostomy should be used if invasive ventilation is to continue
cuffed tube
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
cat 1 C section for fetal brady, Cant intubate, get i gel in. what next?
continue with C section with cricoid on
how much csf proced each day?
450ml
(150 ml present at one time)
what is the response time of a thermistor like? how sensitive is it?
slow
very sensitive
fragile
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
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,
what are the side effects of cimetidine?
CYP450 inhibitor
anti-androgen effects - impotence, gynacomastia and reduced sperm count.
where does the larynx sit in children vs adults?
adults = C3 to C6
children = C2/C3
what happens if you cant pass a suction catheter down a trachea and patient not ventilating?
deflate the cuff - they can potentially orally oxygenate
which is the only agent increasing cerebral blood flow?
ketamine
(and hence increase in ICP)
what electrolyte changes are seen in furosemide?
low, K, Mg, Ca
Can cause hypernatraemia
what is engraved on cylinders?
date of test
test pressure
chemical formula of gas
tare weight
what does the shape and colour of the plastic disc on the neck of a cylinder indicate?
year of inspection
what are U1 and U2 opioid receptors responsible for?
U1 = analgesia and dependance
U2 = resp depression, reduced peristalsis, miosis and euphoria
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.
what inhibits gastrin release?
secretin = released from S cells in duodenem due to acidity
somatostatin = released by D cells of stomach when pH <2
what is the equation for length of tube in children?
age / 2 +12
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
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
what is the max leakage current for CF devices?
single fault = 50uA
multiple = 10uA
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
how is relative risk reduction calculated?
calculate % in each group
find difference = absolute risk reduction
divide difference by control group %
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
name some different phosphodiesterase inhibitors?
milronone, enoximone = selective for PDE III
sildenafil and dipyramidol = PDE V
aminophylline/ theophylline = non selective
how much more lipid soluble and potent is fent than morphine?
x100 more potent
x600 more soluble
what is the narrowest part of the airway in children?
level of crircoid cartilage
adults = laryngeal inlet.
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)
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
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
what does vit B12 bind to in plasma?
Transcobalamins
what does haemopexin bind to in plasma?
free haem
what is a cardiff aldasorber?
passive scavenger
for anaesthetic agents
(not CO2 or N20)
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
what is the mechanism of nicrorandil?
ATP sensitive pottasium channel activator - hyperpolarisation and relaxation of arteriole.
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.
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.
what is the breakdown product of noradrenaline?
VMA
by comt and Moa
how is noradrenaline formed?
from dopamine
via dopamine hydroxylase
what chains make up fetal Hb?
2 alpha
2 gamma
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
what is the max absolute humidity at 37 degrees?
44 g/m3
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
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
how does trimetaphan work?
blocks nAChR
reduces BP by acting centrally and blocking ganglionic transmission.
how does methyl dopa work?
stimulates alpha 2 receptors
name 4 drugs causing gynaecomastia..
spironolactone
digoxin
isoniazid
cimetidine
how long is the cardiac action potential?
300ms
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.
what should ET tube cuff pressure be?
low pressure high vol
20-30cmH20
what important DDI does linezolid have?
acts as a weak non selective MAO inhibitor
hence can precipitate HTN crisis/ serotonin syndrome
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.
which local anaesthetic can cause methamoglobinaemia?
prilocaine
due to o toludine metabolite
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.
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.
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
what is the absolute humidity at 20 degrees?
17 g/m3
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
what is the dose of adrenaline in an arrest in paeds?
10 mcg/kg
e.g. 0.1ml /kg of 1:10000
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
,
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
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.
what is the mechanism behind cardio and neurotoxicity in TCA overdose?
their interaction with VG Na channels
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
what is the induction dose for etomidate?
0.3mg/kg
which roots and cord does the ulnar nerve come from?
C8 to T1
medial cord
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.
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
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.
pathway for NA and adrneline production…
tyrosine –> LDOPA (tyrosine hydroxylase)
LDOPA –> dopamine (L DOPA decarboxylase)
dopamine –> NA (dopamine hydroxylase)
NA –> adrenaline (PNMT)
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
what % does renal blood flow increase in pregnancy?
50%
which hormone has ADH like activity?
oxytocin
what is the half life of ADH?
5 mins
which enzyme converts NA to adrenaline
PNMT (phenylethanolamine N-methyltransferase)
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)
name drugs used for SVT, VT and both
Supraventricular only: digoxin, verapamil, adenosine.
Ventricular only: lidocaine, phenytoin.
Both: amiodarone, beta-blockers, disopyramide, procainamide, fleicanide.
name 2 B2 agonsits
salbutamol
terbutaline
can give either in asthma
contraindications to epidural spinal?
patient refuses
infection at the site or sepsis
hypovolaemia - severe
aortic stenosis / HOCM
increased ICP
coagulopathy
how should methadone be managed perioperatively?
continue
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
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
colour coding of inhaled anaesthetic agents…
Red – halothane
Purple – isoflurane
Yellow – sevoflurane
Blue – desflurane
Orange – enflurane
state the respiratory quoient for different diets?
fat is 0.7, for protein 0.8, and for carbohydrate 1.0.
how does GABAPENTIN work?
blocks L type Ca channels
also modulates GAD which increases levels of GABA
what is oral bioavailability of tramadol like?
90%
similar IV and oral dose
does tramadol have isomers
yes exists as racemic mixture
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)
how is TPN calculated?
30-40ml/kg / day = fluid
30kcal/kg/day - medical
45 cal/kg/day - post op
protein - 1kg/day post op
what does pregnancy do to MAC?
decreases it
where do osmotic diuretics work?
loop of henle (and PCT)
e.g. mannitol
where does amiloride work?
DCT
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.
safe dose of prilocaine?
6mg/kg
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
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. % -%
which is quicker capnography or pulse oximetry?
capnography - delay of around 3 seconds
pulse ox = 20sec
is gluconeogesis aerobic or anaerobic?
anaerobic
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.
what is larger peak exp or peak insp?
In health, the peak expiratory flow rate exceeds that of inspiration.
what is the function of fusidic acid?
inhibits protein synthesis - ribosomal function.
how does B2 result in bronchial smooth muscle relaxation?
Gs, cAMP, PKA, MLCkinase inactivation ! also indirectly activates MLCphosphatase
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
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)
what rate does a wrights respirometer rotate? which part of breathing circuit is it positioned?
150 revolutions per litre of gas flow
expiratory limb
how will wrights respirometer work at low TV?
under estimate due to friction
what can suggamadex be used for?
roc
vec
(more effective with roc)
which diuretics work in Distal convoluted tubule?
Early distal convoluted tubule: thiazide diuretics.
Distal convoluted tubule: amiloride
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
how long does a battery pacemaker typically last?
8-10 yrs
what is this…
halothane
Mr = 197
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.
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
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.
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
which infusion should you avoid sunlight with?
sodium nitroprusside
need to wrap giving sets in tinfoil
otherwise liberation of cyanide ions
what do you dilute sodium nitroprusside in?
5% dextrose
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
is halothane hepatitis more common in adults or children?
adults
risk factors
obesity, female sex, pre-existing liver disease and repeated exposure to halothane.
how is O2 content calculated?
(1.34 x Hb x SpO2) + (0.0225 x PaO2)
0.003 for mmHg
what is larmor frequency?
rate of precession of a magnetic moment
depends on magnetic field stretnght and the gyromagnetic ratio
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
colours of filters on breathing machines…
yellow – breathing filters microbes
Blue – heat and moisture exchange.
Green – both
which antibiotic causes peripheral neuropathy?
nitrofurantoin & metronidazole & ciprofloxacin
irreversible
mechanism of
dipyramidole
tirafiban
clopidogrel
dipyramidole - phosphodiesterase
Clopidogrel - ADP (P2Y12 receptor)
tirafiban - GPIIb/IIIa
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
define mixture…
2 or more substances dispersed through one another whose consituent parts retain their original identity
define solution
solvent and solute combine to make a new homogenous substance. not a mixture
define suspension
A suspension is two or more substances mixed together where the heavier substance will eventually settle out under gravity.
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
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.
what is the normal systemic vascular resistance value?
800-1600 dyn.s.cm-5
in pregnancy what is main cause of increased CO?
Stroke volume (due to preload)
also some increase in HR (25%) but mostly SV (30%)
what is the advantage of the miller blade?
straight blade
used in paeds to lift epiglottis out the way
what % receptors occupied per ToF count?
0 twitches = 95-100%
1 twitch = 90%
2 twitch = 80%
3 twitches = 70%
all twiches <70%
what is function of long inlet port on the vapouriser?
prevent bypass channel becoming contaminated with retrograde flow
why are equal volumes used in bypass channel and vapourising chamber?
ensure any gas expansion is equal .
how do saline filled lungs change compliance?
reduces surface tension hence increases compliance
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.
define sterilisation
The process of rendering an object free from all pathogenic organisms including bacterial spores
define disinfection…
Disinfection: The process of rendering an object free from all pathogenic organisms except bacterial spores
which organelle is highly present in Z3 of liver?
Smooth endoplasmic
for drug metabolism.
what is the hepatic artery a branch of?
coeliac trunk
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
what is the atm pressure at 5500 meters?
50 kpa
roughly 0.5atm
what is a notch filter and bandwidth filter?
notch filter = removes specific wavelength
bandwidth = allows through band of wavelegnth
what current is delivered in PTC?
50Hz 5 seconds
followed by 3 second pause
1 hz x 20 stimuli
which electrodes are seen in pH measurements ?
reference electrode = mercury / calomel (or Ag/AgCl) + KCL
measuring = Ag/Agcl, buffer solution
what is meant by population inversion in LASER?
state where lasting medium where more atoms are high energy state than ground energy state
what does a sieving coefficient of 1 mean?
freely filters across and equilbriates with plasma e.g. glucose
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
name 3 types of meds used in pulmonary artery HTN
endothelin antagonists = bosentan, ambrisentan
prostacyclin agonist = iloprost, epoprostenol
PDE5 inhibitors = sildenafil
what is a supramaximal stimulus?
A supramaximal stimulus is typically 25-50% higher than that needed to produce a maximal response.
why is having an increased horizontal width beneficial of an i gel?
prevents rotation
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
how does erythromycin work as a prokinetic?
mimics motilin
agonist at motilin receptors
which conditions lead to inaccuracies of wedge pressure estimating LA pressure
mitral stenosis/ regurgitation
atrial myxoma
pulmonary veno occlusive disease
cardiac tamponade
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.
how does Calcium conc compare in CSF to plasma?
lower in CSF
how does Mg compare in CSF to plasma
higher in CSF
name phase 1 reactions in liver
by CYP450
oxidation, reduction, hydrolyiss
dealkylation and deamination
how does rate of elimination compare to clearance?
rate of elim = clearance x plasma conc
what do I cells of stomach secrete?
Cholecystokinin
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.
what should stroke volume variation % be to be fluid responsible
if <10% unlikely fluid responsive
how do lisinopril and enalapril vary in metabolism?
enalapril - prodrug, metabolised by liver
lisinopril not metabolised, excreted unchanged
How does pethidine solubility and potency compare to morphine?
relative lipid solubility x 30 t
relative potency x 0.1 that of morphine.
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
target CO2 in head injury?
4.5-5 kPa.
what is the effect of bicarb on local anaesthetics?
sometimes added to increase unionised form
what is more potent lidocaine or bupivacaine?
bupivacaine
compare lipid solubility of fentanyl and alfent?
fent = 600x morphine
alfent = 90x morphine
what is more potent alfent or fent?
fentanyl
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.
mechanism of ciprofloxacin?
fluroquinolone
DNA gyrase/ topoisomerase inhibition - DNA synthesis inhibition
mechanism of rifampicin
RNA polymerase inhibition
mechanism of aminoglycosides? example drug?
gentamicin
30S inhibition
erythromycin class?mechanism
macrolide
50S inhibition
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.
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).
what is Aliskiren?
direct renin inhibitor
prevents angiotensinogen to angiotensin 1
equation for loading dose…
Loading dose (mg) = concentration (mg/ml) x volume of distribution (ml)
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
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%.
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
mechanism of labetalol?
non specific alpha and beta antagonist.
what size mesh do epidural filters have?
0.22 microns
what is the newton valve?
valve used in penlon nuffield so it can be used in paeds by preventing volutrauma.
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.
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
mechanism of action of glibenclamide?
sulphonylurea
colours for venturi for % O2
blue = 24%
white = 28%
orange = 31%
yellow = 35%
red= 40%
green = 60%
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
-
How many vaporisers in tri service ap?
2x Oxford min
What is more potent morphine or it’s metabolites ?
Morphine 6 glucuronide x13 more potent
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
