Random Questions Flashcards
Discuss the blood supply to the spinal cord
There are two posterior arteries and one anterior artery.
Cervical spinal cord receives its blood supply from vertebral and radicular arteries.
Thoracolumbar region receives its blood supply from the radicular arteries only.
Posterior arteries arise from cerebellar arteries.
Anterior artery arises from vertebral arteries.
-Both receive collaterals from intercostal arteries in the thorax and lumbar arteries in the abdomen. The radicular arteries arise from the descending aorta.
What is another name from Beck’s Syndrome?
Anterior spinal artery syndrome
-It is flaccid paralysis of LE, bowel and bladder dysfunction, loss of temperature and pain sensation.
PROPIOCEPTION IS INTACT
Losartan and its affect on lithium
It increases lithium reabsorption by the kidneys
Minimum amount of time for a DES
-6 months (1st gen)
-12 months (2nd gen)
-ACS patient (12 months always)
BMS = 1-3 months
What does SSEP monitor?
Sensory only = dorsal part of the spinal cord.
Drugs that interfere with SSEP decrease amplitude and increase latency (VA, propofol, barbiturate, midazolam, diazepam
-ketamine, precedex, etomidate, opioids, droperidol are all okay
What is indicative of neural injury for SSEP?
-50% decrease in amplitude
-10% decrease in latency
What is the partition coefficent?
The ratio of the volatile agent in the blood compartment relative to the air compartment at equilibrium. Aka the volatile agent partitions between the blood and the alveolus at equilibrium.
The number of parts in the blood is always relative to 1 part in the alveolus.
B/G of sevoflurane = 0.65 = 65 parts in the blood for 100 parts in the alveolus. THus, the onset is faster because FA equilibrates with FI faster.
SOLUBILITY DECREASES AS THE TEMPERATURE OF THE BLOOD IS INCREASED
What are the 3 components of LA building wise
- aromatic ring = lipid solubility
- intermediate chain = metabolism and allergy potention
- tertiary amine = water solubility
How does the opioid receptor work?
GPCR –> inhibits AC –> decreases cAMP
-presynaptic nerve decreases calcium influx
-postsynaptic nerve increases potassium efflux
What is the dose range for cocaine?
1.5 - 3 mg/kg
What is the dose range for physostigmine?
15 - 60 mcg/kg
Discuss methodone
Racemic mixture that blocks all four processes of pain transmission.
-D-isomer = antagonizes the NMDA receptor which inhibits serotonin and NE reuptake
-L-isomer = antagonizes the opioid receptor
also…. prolongs QT
What are the final products of soda lime reaction?
CaCO3 + NaOH (Calcium carbonate and sodium hydroxide)
CO2 + H2O > H2CO3 + NaOH > NA2CO3 + H2O + heat > NA2CO3 + CaOH2
What is brugada syndrome?
-Ion channelopathy in the heart
-More common in southeastern asian males
-RBBB, ST elevation in V1 - V3
WPW and EKG changes
short PR
Delta wave (premature upsloping of the R wave)
wide QRS
Hydralazine
Direct acting vasodilator that increases cGMP. The baroreceptor reflex is preserved!! Tachycardia is common.
Dosing = 2.5 - 20 mg
Onset = 15 - 20 minutes
DOA = 6 - 12 hours
RISK OF LUPUS SYNDROME
When is sodium bicarbonate indicated during metabolic acidsosi?
When the pH is < 7.2. It should NEVER be used for respiratory acidosis because the bicarbonate dissociates into more CO2. This worsens the patients condition.
-Calculate the difference between the patient’s HCO3 and normal.
-Multiply by the patients weight (kg) and 0.3
-Divide by 2
How does hyperventilation reduce ionized calcium?
H+ are displaced from plasma proteins.
Calcium takes its place.
S/S of Hypercalcemia
(> 12)
-HTN, short QT, kidney stones, polyuria, hypotonia, N&V, bone pain, cognitive dysfunction
‘stones, thrones, bones, belly groans, and psychiatric overtones’
What are the sesory dermatomes for GU?
Bladder = T11 - L2
Prostate = S2 - S3
C-fibers
transmit slow pain
diameter = 0.4 - 1.2 micrometers
unmyelinated
-tourniquet pain come from these guys.
Is carbon monoxide a 2nd messenger?
yes
what is serotonin derived from
tryptophan –> 5 hydroxytryptophan –>. serotinin
*metabolized by MOA
What congenital conditions require a patent PDA to maintain systemic perfusion?
-hypoplastic left heart
-tricuspid or aortic atresia
-aortic stenosis
-coarctation of the aorta
use 21 fio2 % to keep it open
where is the only area in the heart that does not contain a fibrous barrier?
the bundle of His (AV BUNDLE)
the fibrous sheet acts as a gatekeeper that directs all impulses to the AV bundle. occasionally, an aberrant pathway may penetrate the fibrous barrier causing arrythmias
how long does it take for an impulse to travel from SA to AV
0.03 seconds
how long does it take for impulses to travel through atrioventricular node
0.09 seconds (conduction is delayed)
how long does it take for impulses to travel through atrioventricular bundle?
0.04 seconds.
in total, there is a built-in 0.16 second delay before the impulse from the SA node reaches the ventricles
bundle branches to purkinje fiber conduction timinig
0.06 seconds
moderate aortic stenosis numbers
peak velocity = 3 - 4 m/s
mean gradient = 20 - 40 mmHg
valve area = 1-1.5 cm2
severe AS numbers
peak velocity = > 4 m/s
mean gradient > 40 mmHg
valve area < 1
mild aortic stenosis numbers
peak velocity = 2.6 - 2.9
mean gradient < 20
valve area > 1.5
which cell type is responsible for initiation of thrombosis?
endothelial
-its negative charge repels platelets.
releases platelet inhibitors (NO, prostacyclin I2)
what characterizes severe mitral regurgitation?
regurgitant fraction > 50%
enlarged LV
> 60 mL/beat
enlarged LA
what is the main factor for EDP vs EDV
pericardium compliance
what two conditions contribute to silent MI?
HTN
DM
VSD & pulmonary blood flow relaationship
increases pulmonary blood flow d/t volume overload
TOF and pulmonary blood flow relationship
decreased pulmonary blood flow due to obstruction
how does truncus arteriosis cause cyanosis?
common mixing chamber
How do you calculate the arteriovenous oxygen difference
Cao2 - Cvo2
(1.34 x hgb x spo2) - (1.34 x hgb x svO2)
What is Kawasaki’s disease
-children
-fever, vasculitis, red strawberry tongue, cervical lymphadenopathy, swollen hands & feet, inflamed mucuous membranes
-affects CORONARY ARTERIES AND MEDIUM SIZED ARTERIES
aka “mucocutaneous lymph node syndrome”
What is Wegener’s granulomatosis?
necrotizing granulomas lead to vasculitis (inflamed arteries) in the airway, lungs (hypoxia), CNS, kidneys
-friable, necrotic tissue in the airway bleeds easily. tracheal granulomas reduce tracheal diameter.
Takayasu’s Arteritis
-occlusive disease of proximal aorta and its main branches
‘pulseless disease or occlusive thromboaortopathy or aortic arch syndrome’
thromboangitis obliterans
-inflammatory vasculitiss that ultimately occludes the small and medium size arteries and veins in the extremities. s/sx like Raynaud’s
-d/t smoking
-aka ‘buerger’s disease’
kussmaul’s sign and CVP waveform
x and y descents are exaggerated
where do dihydropyridines bind?
vsm @ outside the channel
where do phenylalkylamines bind?
myocardium @ inside the L-type calcium channel, alpha 1 subunit
where do benzothiazepines bind?
myocardium (unsure of binding site)
what can causing HFpEF?
DIASTOLIC HF (s4)
-AS, IHD, long standing HTN
-concentric hypertrophy
-old age
-valve stenosis
-HoCM
-cor pulmonale
-obesity
How is FA/FI influenced by blood gas solubility?
Agents with low solubility undergo less abssorption by the blood.
-FA/FI of an agent with low solubility is more affected than the agent with a high solubility.
des > nitrous > sevo > iso
how do you ventilate a patient with bullae?
Small TV
High RR
SV until chest is opened.
Pyloric stenosis
Medical emergency
-hypokalemic, hypochloremic, metabolic alkalosis
what is deadly nightshade?
Belladonna
-anticholinergic OD = flushing, mydriasis, dry mouth, confusion, hallucinations, hyperthermia, tachycardia
treated with physostigmine 15 - 60 mcg/kg
What drugs interfere with the accuracy of SSEP?
decrease amplitude & increase latency
-VA, N2O, Propofol, Barbiturates, Midazolam, Diazepam
Which drugs do NOT impair the SSEP signal?
ketamine
dex
etomidate
opioids
droperidol
1mmHg in PACO2 CBF changes by how much?
same direction by 1 - 2 mL/100g/m
medial rectus
adduction
CN3
lateral rectus
abduction
CN6
superior rectus
supraduction
CN3
inferior rectus
infraduction
CN3
superior oblique
intorsion and depression CN4
inferior oblique
extorison and elevation
CN3
which chemotherapeutics belong to the antitumor abx class?
bleomycin
doxorubicin
what is different about piston-driven ventilators?
-it will not consume O2 in the event of oxygen pipeline failure
-2 pressure relive valves (PPV and Negative Pressure). PPV aat 75 cmH2O. Negative pressure at -8 cm H2O.
-Incorporate fresh gas decoupling.
What med causes torsades
methadone b/c prolongs QT interval
QT interval > 500 ms = increased risk of lethal tachyarrythmias
Dose range for cocaine
1.5 - 3 mg/kg
do not exceed 200 mg
distances btw CVL insertion and proper tip position
subclavian = 10 cm
right IJ = 15 cm
left IJ = 20 cm
femoral vein = 40 cm
right median basilic = 40 cm
left median basilic = 50
what happens if the vagus n is injured?
unilateral = hoarseness
bilateral = aphonia
external branch of SLN
-unilateral = nothing
-bilateral = hoarseness
internal branch of SLN =nothing
RLN
-unilateral = hoarse
bilateral = stridor
what are risks associated with non-OB related surgery on a parturient?
DAW
increased aspiratoin
growth restriciton, LBW, demise, preterm labor
phenelzine
inhibits MAO
-increases 5HT and NE in the brain.
onset of delirium vs POCD
PCOD onset = 6 months
delirium = 1 - 5 days postop
recommended bladder width of blood pressure cuff
40% of the circumference of the extremity
circumference x 0.4 = appropriate width
what pharm agents will precipitate carcinoid crisis?
succ, thiopental, epi, atracurium, NE, isoproterenol
MG facts
pregnancy exacerbates symptoms
-Anti-AchR IgG antibodies cross the placenta = weakness in neonate for 2 weeks
how to calculate therapeutic index
median lethal dose/ median effective dose
Ether vs Ester
Ether = ROR
Ester = RCOOR
spinal hematoma must be fixed within how long
8 hours
desflurane b/g
0.42
celiac plexus
T5 - T12
-does not contain somatic fibers
-SE = hOTn, shoulder pain, diarrhea
is the aging brain senssitive to etomidate?
no
but it is to propofol and VA
cardioversion for aflutter, afibb etc
50 - 100 J
define PAH
mean PAP > 25 mmHg
PAOP no greater than 15
where should the distal tip of the LMA sit?
upper esophageal sphincter = cricopharyngeus muscle
Proseal vs Classic maximum PPV
aka LMA supreme = 30 cm H2O vs 20 cm H2O for classic
pulmonary edema what type of cardiac shunt
right to left
if it exceeds > 50% oxygen will not help
if the case is delayed, how often should you re-dose BICITRA
1 hour after initial dose.
Head elevated on bed. What axes are aligned.
PA and LA
Head with head extension only.
PA and LA
s/s of subclavian steal
syncope
vertigo
ataxia
hemiplegia
what triggers porphyria
ALA synthase stimulation
stress
npo status
cyp450 induction
treat: heme arginate and glucose
what is the most potent amnestic? DOA?
lorazepam = 6 hours of amnesia
uptake for LA
interpleural > intercostal > caudal > brachial plexus
what does the median nerve supply?
palm of hand
ventral region of thumb
distal portions of fingers
discuss hemophilia A
severe is defined as < 1% of F8. PTT will be prolonged severely.
PT is normal because TF 7 dependent pathway is not affected.
Treat: FFP, cryo, F8
VW disease
qualitative platelet dysfunction.
Type 1 = mild - moderate reduction in vwf
2 = vwf produced doesnt work well
3 = severe reduction in vwf
treat: ddavp 0.3 mcg/kg
what is gap vs non-gap acidosis
gap = due to accumulation of H + (lactic acidosis, ketoacidosis, RF)
non-gap = d/t loss of bicarbonate or increased chloride (diarrhea, renal tubular acidosis, excessive NaCl admin)
how much fluid is absorbed during TURP resection?
10 - 30 mL/m
EBL = 2 - 5 mL/m
what is the most common TEF?
C = upper esophagus dead ends, lower communicates with distal trachea
what is neonatal total body water
80%
ecf = 40%
albumin and aaag reduced. 5 - 6 months until they reach adult levels
what is orthodromic AVRT
antergrade conduction through the AV node
normal QRS
no delta
Retrograde P wave after QRS
what is antidromic AVRT
retrograde conduction through the AV Node
wide QRS
no P wave
what volume increases in the parturient?
inspiratory reserve volume because FRC decreases.
hypokalemic periodic paralysis
anything that decreases the serum potassium will exacerbate this disease
-acetazolamide is useful for treating both hypo and hyperkalemic periodic paralysis.
it protects against hypokalemia by creating a non-gap acidosis. it protects against hyperkalemia by promoting potassium excretion.
which lead will demonstrate rhythm abnormalities?
lead II bipolar
what is reflex sympathetic dystrophy?
type I CRPS
how to treat gout
-gout is an excess of uric acid in the blood. primary gout is a result of a genetic defect of purine metabolism.
-liberal hydration, alkalize urine with sodium bicarb, allopurinol to inhibit purine conversion to uric acid, colchicine to reduce inflammation
decreased renal blood flow labs
pre-renal oliguria
-concentrated urine and low fractional excretion of sodium. the body is holding sodium and water in an effort to preserve intravascular volume
urine sodium < 20
fractional excretion of sodium < 1%
gastrin stimulates
pepsinogen secretion
secretin stimulates
bile flow
motilin stimulates
upper GI motility
