Pastest Flashcards
What is normal result of csf?
Including pH , glucose, chloride , protein and osmolality
pH 7.33
Glucose 3mM
Chloride 120
Osmolality 295
Protein 30mg/l
More acidotic, higher chloride, lower glucose and protein than plasma. Same osmolality
How does anterior spinal artery syndrome present ?
Bilateral
Loss of motor , pain and temp
Dorsal columns are spared - vibration and proprioception
How does posterior spinal artery syndrome present ?
Loss of dorsal columns - vibration and proprioception
Bilateral
How does posterior spinal artery syndrome present ?
Loss of dorsal columns - vibration and proprioception
Bilateral
Total number of reactions in glycolysis ?
10
Why can glycosuria be normal in pregnancy?
Increase in GFR
Due to renal vasodilation
The increase in renal blood flow also reduces the tmax for glucose reabsorption
What is the narrowest part of an airway in a child?
Level of cricoid cartilage
What muscles do the superior and inferior laryngeal nerve supply ?
Superior - external branch - only muscle is the cricothyroid - tense and lengthens vocal cords
Inferior laryngeal a.k.a recurrent - the rest of intrinsic muscle of larynx
What pressure and rate is C02 inflated in pneumoperitoneum?
Rate of 4-6L/min
To a pressure of 10-20mmHg
If higher can cause bradycardia
What differences are there in dependant and non dependent lung in ventilated and spontaneous ventilation patient ?
Dependant lung - lung on bottom
Independant lung - on the top
Perfusion favours the dependant lung in both cases
In PPV - the non dependent lung is ventilated better
In SV- the dependant lung is ventilated better
What is a square wave response of valsalva?
Normal valsalva - map increases with valsalva and as it’s released there is a drop in map and then back to baseline
Square wave - map increases and then comes back to baseline without any over/ under shoot.
Seen in
What are the parts of the brachial plexus ?
Roots c5,6,7,8,T1
Trunks - sup, middle, inferior
Division - anterior and posterior
Cords - lateral , posterior, middle
Branches
‘ Real Texans drink cold beer’
What are the parts of brachial plexus ?
Roots
Trunks - superior inferior and middle
Divisions - posterior and anterior
Cords - middle, lateral and posterior
Branches
How does nuclei compare in skeletal, smooth and cardiac muscle
Skeletal - multinucleated, peripheral
Cardiac - single central
Smooth - single central
What is the speed of USS in different tissues ?
Air - 300m/s
Soft tissue - around 1500m/s
Bone - 4000m/s
Speed of USS in tissue is influenced by density and elasticity of the tissue
Which vessel most likely to cause a subarachnoid haemorrhage ?
Anterior communicating artery
What do the following levels of spinal block result in … C3- C5, c8-t1, T4 , T10
C3 -C5- phrenic nerve - respiratory depression , will need GA and intubation
C8-T1 - weak hand grip and parasthesia
T4 - loss of sensation to nipple and sympathetic block of heart
T10 - belly button
What is meant by a high spinal ?
Above level of T4
If there is bradycardia with a spinal what can you say about the block ?
Involves sympathetic NS to the heart - T1 to T4
How are nerve axons classified ?
By diameter ..
A - largest
- further divided in a,b, g,d
B
C - smallest
What fibres carry -
Motor
Sharp pain
Pre ganglionic autonomic
Proprioception
Pressure
Motor to muscle spindle
Aa - motor and proprioception
Ab - touch and pressure
Ad - sharp pain and temp
Ag - motor to muscle spindle
B - pre ganglionic ANS
C - dull pain, pressure
What is the alveolar gas equation
PA02 = (Patm-6.3)x0.21. - pa o2/0.8
What pressure is recommended for cricoid in RSI?
30N -40N
10N when patient is awake
What can happen to partial pressure of 02 in muscle during exercise ?
Can drop to as low as 0.13kpa in mitochondria
What is the max skeletal blood flow in strenuous exercise ?
22L/ min
How is renal blood flow altered in exercise
Drops from 1L/min to 250ml/ min
What happens to pulse pressure in exercise
Systolic increases
A little increase in diastolic
Pulse pressure widens
Which block can paralyse the recurrent laryngeal nerve for planned awake fibrooptic intubation?
Translaryngeal nerve
Blocked at level of cricothyroid membrane
What is the dose of ropivacaine ?
3mg/kg
What is the dose of ropivacaine ?
3mg/kg
How does miosis affect intraocular pressure ?
Reduces aqueous humour production
Reduces intraocular pressure
How does oxygen levels in blood affect intraocular pressure ?
Hypoxia causes vasodilation and increases intraocular pressure
What is the main energy source of myocardium
fatty acids contribute to 60%
Which artery in leg should be palpated to give indication of perfusion of whole limb?
Dorsalis pedis - continuation of anterior tibial artery
How does normal saline distribute in the acute phase of IV fluid administration?
Only to ECF with 75% interstitial and 25% plasma
Which chemical can estimate plasma volume ?
Evans blue dye
Radioactive albumin
Which chemical estimates total body water
Deuterium oxide
What chemical can measure extracellular volume ?
Mannitol
What are oxygen sats in different parts of the fetal circulation ?
Umbilical vein - 80%
Descending aorta 55-60%
Superior vena cava - 25%
What are oxygen sats in different parts of the fetal circulation ?
Umbilical vein - 80%
Descending aorta 55-60%
Superior vena cava - 25%
What are the ecg changes for hypercalcaemia
Short QT
Other symptoms of high ca - moans, groans , stones - constipation, urine stones, depression
How does magnesium toxicity cause muscle weakness
Inhibition of VG ca release
Prevents exocytosis of Ach
What is the path for CSF?
Choroid plexus
Lateral ventricles
Foramen monro
3rd ventricle
Aqueduct of sylvius
4th ventricle
Foramen lushka and magendie
Subarachnoid space
What is the path for CSF?
Choroid plexus
Lateral ventricles
Foramen monro
3rd ventricle
Aqueduct of sylvius
4th ventricle
Foramen lushka and magendie
Subarachnoid space
What are the effects of ANP
Medullary collecting ducts to promote sodium excretion
Afferent arteriolar vasodilation - increases GFR
Promotes blood flow to vasa recta which promotes washing away of electrolytes and reduces osmotic gradient hence less reabsorbed
Inhibits renin
How is ards defined ? Clinical criteria ?
Symptoms within 1 week
Bilateral opacities
Resp failure not explained by cardiac failure
Hypoxia
Which glut transporter is sensitive to insulin ?
GLUT4 in skeletal muscle and adipose
How is glucose absorbed from the intestine ?
SGLT1 - na/glucose symporter - on luminal membrane
GLUT2 - on basolateral membrane
Where are GLUT1 found ?
Insulin independant
Red cells and brain
What do the waves on JVP relate to ?
A wave - atrial systole
C wave - ventricular systole - causes bulging of the valve towards atria
X descent - early diastole - atrial filling and so emptying of vena cava
V wave - early diastole - continued atrial filling against closed tricuspid valve
Y descent - tricuspid valve opens and atria empty
What do the waves of a JVP demonstrate
A wave - atrial systole
C wave - ventricular systole bulging of tricuspid valve upwards
X descent - atrial filling - removed from vena cava
V wave - atrial filling towards end of diastole
Y descent - tricuspid valve opens and atria drain
How is pregnancy in HIV managed at point of delivery ?
Viral load needs to be <1000 copies within 4 weeks of delivery for vaginal
Otherwise c section
What is the rarest blood type ?
AB negative
1 % prevalence
Do thyroid receptors have greater affinity for T3 or T4?
T3
How many isoforms of thyroid receptor are there ?
3
How is the standard error of mean calculated ?
SD / root no. Of values
What is the gold standard measurement of cardiac output measurement ?
Thermo dilution
Uses a pulmonary artery catheter with a thermister at the tip
Inject cold inject
Plot temp overtime on semi log scale
Use Stewart Hamilton equations to measure
What is the gold standard measurement of cardiac output measurement ?
Thermo dilution
Uses a pulmonary artery catheter with a thermister at the tip
Inject cold inject
Plot temp overtime on semi log scale
Use Stewart Hamilton equations to measure
Which of the catecholamines is metabolised in lungs?
NA
(Adrenaline and dopamine aren’t )
List the metabolic actions of the lung ?
Metabolism of serotonin, NA
Production of ATII
Arachidonic acid metabolism to prostaglandins and leukotrienes
Production of NO, endothelin and histamine
Which cells are the pacemaker of the GIT?
Interstitial cells of cajal
Which symptoms do anterior and middle cerebral artery strokes present in ?
Anterior - leg weakness predominant and sensation loss
Middle - arm weakness predominant and slurred speach
What is the most common site for subarachnoid haemorrhages caused by aneurysm ?
Anterior communicating artery
What is the most common site for subarachnoid haemorrhages caused by aneurysm ?
Anterior communicating artery
What part of the brain sets the temperature set point ?
Posterior hypothalamus
What neurotransmitters are involved in temperature regulation?
Serotonin , NA , dopamine, PGE- anterior hypothalmus
Ach - in posterior hypothalamus
Which receptors in skin act as cold and warm receptors?
Bulbs of Ruffini - hot
Bulbs of krause- cold
Which part of hypothalamus responds to hot vs cold ?
Hot - anterior
Cold - posterior
how is bradycardia treated in transplanted heart?
transplanted heart lacks innervation so cant block ACh receptors i.e. blocking parasympathetic response as there is none.
instead need to act directly on heart - give adrenaline to act on B1 receptors
Which muscle relaxant should be avoided in acute amphetamine toxicity ?
Succinylcholine
what does grip strength correlate with?
total body protein
fist grip is a validated measure of nutritional status
what is the cormic index?
ratio of sitting height to standing height
can cormic index affect BMI?
yes -
cormic index varies between populations
cormic index can be used as a correction factor to make BMI as an assessment of nutritional status more valid
how accurate is a DEXA scan in determining body fat %?
overestimates body fat % in those with high fat
underestimates body fat % in those with low fat
which level of albumin is associated with malnutrition?
less than 10mg/dl
what are the initial steps in managing an airway fire?
remove ET tube
turn of O2
wash with normal saline
which vasopressin receptors are in the kidney?
V2
where are vasopressin V1 receptors found?
vascular smooth muscle in
sphlanchnic
renal
coronary
and systemic vessels
Gq - vasoconstriction
where are vasopressin V3 receptors found?
pituitary - involved in regulating release of other hormones.
Also know as V1b
Also found in pancreas involved in hormones release
what type of receptors are vasopressin receptors?
GPCR
V1 - Gq
V2- Gs
V3 - Gq
which antibody is most abundant in human serum?
IgG
which Ab crosses the placenta?
IgG
which Ab is mostly present at mucosal surfaces?
IgA
which is the least abundant serum Ab?
IgE
which ab is primarily found in blood and lymphatics?
IgM
what cells make up the reticuloendothelial system?
kupffer cells
microglial
osteoclasts
pulmonary alveolar macrophages
what is first step in managing acute severe asthma?
salbutamol nebs / ipratropium nebs
IV MgSO4
IV hydrocortisone
if refractory IV aminophylline
last resort intubation
which B blockers are selective to B1? hence ok in asthma?
BEAM
bisoprolol
esmolol
atenolol
metoprolol
which B blockers should be avoided in asthmatics?
propanolol
timolol
sotolol
with caution
labetolol
Carvedilol
what is the mechanism of action of fluoexetine?
SSRI - serotonin selective reuptake inhibitor
what is the mechanism of entacapone ?
COMT inhibitor
used to reduce breakdown of dopamine in parkinsons
which drugs should be avoided with ephedrine?
highest risk irreversible MAO - A inhibitors e.g. phenelzine
direct acting sympathomimetics - metaraminol
TCA
(MAO- B are not responsible for catecholamine breakdown so can be used, COMT enzymes are not main mechanism of NA breakdown so COMT inhibitors can be used)
what ecg changes are associated with hyperkalaemia?
peaked T
wide QRS
flat P waves
which nervous system and receptors innervate sweat glands?
Sympathetic
cholinergic
M2
what is the mechanism of action of neostigmine?
carbamylation of cholinesterase
it is broken down by cholinesterase but takes longer than ACh
which drug helps to maintain patent ductus arteriosus?
Prostaglandin E2
what closes patent ductus arteriosus with birth?
lack of prostaglandins from placenta
higher O2 conc
what drug closes patent ductus arteriosis?
indomethacin - reduces prostaglandins
what is needed in context of a bleed and high INR on someone on warfarin?
prothombin complex concentrate - factors 10,9,7,2 (1972), protein C and S
which antibiotics are bacteriocidal vs bacteriostatic?
bacteriocidal
B lactams - penicillins
glycopeptides
fluroquinolones
metronidazole
bacteriostatic:
macrolides
tetracyclines
trimethroprim
why is meperidine/ pethidine not good in renal failure?
meperidine metabolite = normeperidine = seizures and 50% activity which can accumulate in renal failure
which is more degraded by hoffman elimination and hence better in renal failure of the neuromuscular blockers?
CISATRACURIUM
what is LD 50 in pharmacology? how does this relate to therapeutic index?
lethal dose for 50%
if LD50 and ED95 are close - narrow therapeutic index
which nerve is damaged to result in vocal cord being partly held in adduction/ abduction? what muscles does this supply?
recurrent laryngeal
all intrinsic muscles except cricothyroid
which nerve innervates cricothyroid muscle?
superior laryngeal
which TCI model is used for paeds ?
paedfusor
which cranial nerve is most likely compressed with tumours at cerebellopontine angle?
CN VII
leads to ipsilateral motor loss - drooping of face and loss of ipsilateral taste.
also parasympathetics - reduced tear and salivation
what is the equation for Cerebral perfusion pressure?
CPP = MAP - CVP OR
CPP = MAP - ICP
(whichever is higher out of CVP and ICP is used).
what physiological factors increase cerebral blood flow?
hypoxia
hypercapnia
reduced viscosity
increased MAP
reduced CVP
reduced ICP
ketamine (other agents reduce it)
how much can skeletal blood flow increase at rest to exercise?
1L/min to 22L/min
highest increase of all organs during exercise.
how much can coronary blood flow increase at rest to exercise?
250ml/min to 1000ml/min
how does renal, skin and GI blood flow alter in exercise?
drop in renal and GI
increase in skin to dissipitate heat.
what are ECG changes with hyperMG and hyperCa?
hyper Mg = prolonged PR and wide QRS
hyper Ca = short QT, PR prolonged, potential J waves.
when should hartmans be avoided?
when lactate is high in presence of liver failure.
what nerves should be blocked in inguinal hernia repair if performing regional anaesthesia?
which nerve root does this come from?
ilioinguinal and iliohypogastric
both come from L1
what is the ductus arteriosus?
remnant of patent ductus arteriosus
connects aorta and pulmonary artery
which fluid compartment does evans blue dye measure?
plasma
how is the blood volume of a neonate estimated?
80-90 ml/kg - neonate at term
name the paired cartilages in the larynx..
arytenoid
corniculate
cuneiforms
is the cricoid cartilage paired/ unpaired and a complete or incomplete ring?
unpaired
complete ring
how does ANP act? (Receptor)
increases gaunyl cyclase activity
increases cGMP
what is the armitage rule for local anaesthetic in children for caudal anaesthesia?
0.25% bupivacaine
0.5ml/kg - lumbrosacral block
0.75ml/kg - inguinal hernia
1ml/kg - lower thoracic block
1.25ml/kg - mid thoracic block
what is the blood:gas coefficient of sevoflurane ?
0.65
what makes sevoflurane suitable for day case?
low blood gas partition coefficient - quick offset
which inhalation agent has the lowest blood gas partition coefficient? and hightest?
desflurane = 0.45
halothane = 2.3
what are the nerve roots of the long thoracic nerve?
C5, C6, C7
how does 5% glucose distribute?
equally amongst all compartments
2/3 = intracellular
1/3 = extracellular (of this 3/4 = interstitial and 1/4 = blood)
what are the guidelines for evacuating patients in a fire?
- those nearest the fire
- the most well
- the most unwell
- those in side rooms
how much current reaches the heart in a monophasic defib? and a biphasic defib?
30 A - 40 A in monophasic
15-20 A in biphasic
when is adenosine contraindicated?
symptomatic bradycardia
sick sinus
2nd / 3rd degree HB - unless they have a pacemaker
Asthma
what is a type 1 error?
shows a difference when not actually one
more likely in small study
what wavelengths of light are used by pulse oximeter and which Hb absorbs what?
660nm = deoxy
940nm = oxy
what is a strain gauge?
a device whose electrical resistance varies with strain and this can be used to measure pressure or force applied
e.g. used in invasive BP
what is the best location for thoracocentesis?
8th - 10th intercostal space
mid axillary line
risk of lung injury is reduced here as lung ends up to 8th rib
how much of the following are equivalent to IV morphine…
oral morphine
diamorphine
oxycodone
tramadol
oral morphine –> IV factor of 3
oral oxycodone –> IV morphine factor of 2
tramadol oral 100mg –> IV morphine 5mg
codeine 60mg oral –> IV morphine 2mg
transdermal fentanyl 50mcg/hr = 60mg IV morphine in 24 hours
What level is cricothyroid membrane?
C6
Name 2 direct thrombin inhibitors? Which can be reversed
Dabagatrin - can be reversed
Bivalirubin - can’t
Name 2 direct thrombin inhibitors? Which can be reversed
Dabagatrin - can be reversed
Bivalirubin - can’t
What does metabolic acidosis do to MAC?
Decreases
(Alkalosis has no effect )
In manual mode what can the manley MP3 ventilator be used as ?
Mapleson D
Pneumonic for post intubation hypoxia
Dopes
Displacement
Obstruction
Pneumothorax
Equipment
Stomach distension
What is the pneumonic for causes of traumatic arrest ?
Hott
Hypovolaemia
Oxygen (Hypoxaemia )
Tension pneumonia
Tamponafe
