M5 2014 Flashcards
Innervation of posterior tongue, soft palate, and oropharynx
Glossopharyngeal n. (IX)
Innervation of hypopharynx
Internal branch of superior laryngeal n. (X)
Innervation of larynx and trachea
Recurrent laryngeal n.
Topicalizing anterior tonsillar pillars with lidocaine will anesthetize what nerve?
Glossopharyngeal n. (Only tonsillar, lingual, and pharyngeal branches, not the whole n.)
External branch of superior laryngeal n. supplies motor innervation to what?
Cricothyroid muscle
Blocking inferior aspect of greater cornu of hyoid bone will anesthetize what nerve?
Internal branch of superior laryngeal n., which innervates the hypopharynx
Only muscle responsible for vocal cord abduction
Posterior cricoarytenoid muscle
Only vocal cord muscle NOT innervated by recurrent laryngeal n.
Cricothyroid muscle, innervated by external branch of superior laryngeal n.
Block of recurrent laryngeal n. results in vocal cords being affected how?
Partial adduction. Unilateral block = hoarseness. Bilateral block = stridor and possible airway obstruction
Most sensitive indicator for a difficult intubation
Mallampati class 3 or 4
2nd most sensitive indicator for difficult intubation
Reduced thyromental distance
Highest positive predictive value (PPV) for difficult intubation
History of difficult intubation
Function of type I and type II pneumocytes
Type I: gas exchange
Type II: produce surfactant, smaller and far more numerous than type I
Sensory innervation of lung is provided by which nerve
Vagus nerve
Long thoracic n. innervates what muscle
Serratus anterior
Winged scapula is a result of damage to what nerve
Long thoracic n.
Coronary a. supplying anterolateral wall of LV
Left circumflex
Coronary a. supplying anteroseptal wall of LV
LAD
Coronary a. supplying inferior wall of LV
RCA
Coronary a. supplying inferolateral wall of LV
RCA and LCx
Most patients with atrial flutter have a rapid circuit originating from which chamber of the heart
Right atrium and involving tissue near tricuspid valve
Aortic arch crosses up, over, and behind which main bronchus
Left main bronchus
Aortic dissection creates false lumen in which layer of the aortic wall
Media (intima, media, adventitia)
Risk factors for aortic dissection
Uncontrolled HTN, connective tissue disease, vasculitis, trauma
Course of subclavian vein in relation to anterior scalene muscle
Anterior
Course of subclavian artery in relation to anterior scalene muscle
Between middle and anterior scalene muscles
Course of subclavian vein in relation to first rib
Superior to first rib and inferior to clavicle
Continuation of internal carotid artery in circle of Willis is called
Middle cerebral artery
When does spinal cord move from L3 to L1
By 2 months of age
Superior aspect of iliac crest is at which vertebral level
L4
Innervation of facet joint between 2 vertebrae
Medial branch of the posterior division of spinal nerves
Celiac plexus is located at which vertebral level
L1
Which nerve is inadequately blocked following axillary block
Musculocutaneous nerve which innervates lateral forearm
Medial forearm is innervated by cutaneous branches of which nerve
Ulnar
Relationship of median nerve to brachial artery in the antecubital fossa
Median nerve runs medial to brachial artery
Parasympathetic fibers to the heart arise from
Dorsal vagal nucleus and nucleus ambiguous
The two plexuses arising from parasympathetic fibers to the heart are located between
Aortic arch and tracheal bifurcation
Nicotinic acetylcholine receptors are found in greatest concentration at which heart node
SA node
Sympathetic cardiac nerve fibers course with which coronary artery
Left main coronary artery
How and when is S3 heart sound made
Early diastole when atrial blood reverberates against poorly functioning ventricular walls. S3 is associated strongly with MACEs (major adverse cardiac events)
S1 sound is heard where on an EKG
Just after QRS complex
S2 sound is heard where on an EKG
Just after T wave
S4 sound is heard where on an EKG
Just after p wave. Sound is caused by atrial contraction ejecting blood into a noncompliant ventricle
Where is mixed venous oxygen saturation measured
Right atrium
ATP binding to myosin results in
Release of myosin tension from actin
Amiodarone is what class of antiarrhythmic agent
Class III, a potassium blocking agent which delays phase 3 repolarization.
Side effects of amiodarone
Pulmonary fibrosis, hypothyroidism or hyperthyroidism, transaminitis, peripheral neuropathies
How does glucagon treat beta blocker overdose
Glucagon increases cAMP and therefore protein kinase A
At what heart rate is stroke volume the greatest
60
At what heart rate is cardiac index maximized
120
Reflex when a hypovolemic pt has bradycardia and hypotension when moved from supine to upright
von Bezold-Jarisch reflex. Receptors in left ventricle
Mechanics of alpha 1 mediated vasoconstriction
Phenylephrine -> alpha 1 receptor -> activation of PLC (phospholipase C) -> formation of IP3 (inositol triphosphate) -> Ca release from sarcoplasmic reticulum -> increased contraction
Mechanics of beta 2 agonism
Beta 2 receptor -> cAMP -> uptake of Ca back to SR -> decreased contraction
Mechanics of NO activity
NO -> cGMP -> decreased contraction
Minimum number of days after coronary balloon angioplasty to wait before performing elective surgery
14 days
Slope of dose response curve is determined by
Receptor binding characteristics
Respiratory depression is mediated by which opioid receptor
Mu2
Muscle rigidity is mediated by which opioid receptor
Mu1
Hallucinations are mediated by which opioid receptor
Sigma
Opioid that decreases contractility, increases heart rate, and causes mydriasis
Meperidine, has atropine like structure causing anticholinergic response
Meperidine decreases shivering by agonism of what receptor
Kappa
Effects of opioids that are resistant to tolerance
Constipation and miosis
High doses of which opioid may induce acute opioid tolerance in the PACU
Remifentanil
Baclofen is an agonist of what receptor
GABA-B receptor
Aspirin sensitivity with nasal polyps is associated with what medical condition
Asthma. Samter’s triad
Reason for hypertension and bradycardia during infusion of dexmedetomidine
Cross reactivity with alpha 1 receptor at high doses
Benzodiazepine effects of amnesia is explained by hyperpolarization of
Post synaptic neurons primarily in the cerebral cortex
Benzodiazepine mediated muscle relaxation occurs through gamma subunit agonism of
GABA-A receptor specifically in the spinal cord
Hyperalgesia is mediated by what process
Opioid NMDA agonism, which explains why patients respond well to NMDA antagonists like ketamine, methadone, and dextromethorphan
How does activation of opioid receptors affect potassium conductance
Increase
Opioids that cause inhibition of serotonin reuptake
Meperidine, methadone, tramadol, dextromethorphan.
Pretreatment with what medication decreases incidence of etomidate associated myoclonus
Opioids
how much of etomidate is not metabolized after passing through liver
50%
Why is it that more active neurons are blocked to a greater extent than less active neurons
Sodium channels in the activated or inactivated state have a greater affinity for local anesthetics than in the resting state
rate of systemic absorption of local anesthetic from greatest to least
IV > tracheal > intercostal > caudal > paracervical > epidural > brachial plexus > sciatic > subcutaneous
Adding epinephrine to lidocaine will increase duration of peripheral nerve block by about how much?
50%
local anesthetics bind to which subunit of the voltage-gated sodium channels
alpha
2 ways that epinephrine enhances quality of a nerve block
1) vasoconstriction causing longer period of time that local is exposed to neuron
2) direct adrenergic activation of alpha-2 receptors
exception to the rule of pseudocholinesterase metabolism of ester local anesthetic
cocaine
Why is block onset faster by adding epi to plain local vs. using premixed local with epi?
Premixed solutions are more acidic to prevent degradation of epi
Basic drugs are usually bound to which protein?
Alpha-1-acid glycoprotein
Acidic drugs are usually bound to which protein?
Albumin
Preservative used with amide local anesthetic
Methylparaben
glutamate is an excitatory or inhibitory neurotransmitter?
excitatory
how does opioid agonism change the resting potential of a neuron
make it more negative
brain needs what percent of cardiac output to cover metabolic needs
15-20%
Is obesity a risk factor for POCD postop cognitive decline?
no
what area in the brain is pain sensed?
postcentral gyrus
Norepinephrine is metabolized by what?
Both MAO (monoamine oxidase) and COMT (catechol O-methyltransferase)
which opioid increases cerebral blood flow
sufentanil
external or internal intercostal muscles are used for inspiration?
external
external or internal intercostal muscles are used for expiration?
internal
dead space is what percent of tidal volume in a healthy mechanically ventilated patient?
50%
above what shunt fraction would supplemental oxygen not expect to increase PaO2 by more than 10 mmHg?
40%
Use ventilation-perfusion ratio (VQI) to calculate shunt
VQI = ( 1 - SaO2 ) / ( 1 - MvO2 ). Therefore 99% SaO2 with 75% MvO2 = 0.01 / 0.25 = 4% shunt in healthy person
Decreased FEF 25%-75% (forced expiratory flow) is indicative of what?
early indicator of medium airway obstructive disease. it is theoretically effort independent
FRC is classically lowest when after a surgery?
12 hours postop
General anesthesia will decrease FRC by what percent?
10%
maximal benefit from smoking cessation is how many weeks prior to surgery?
8 weeks or more
Classic EKG findings for a COPD patient
signs of right heart strain such as poor R wave progression, enlarged P waves, RBBB, right axis deviation, low voltage
Abdominal surgery affects residual volume (RV) how?
increases it by 10%. expiratory reserve volume is decreased by 25%
Best surface anatomic estimate for level of the carina
sternal angle
best marker for dynamic lung compliance
peak pressure
Ach receptor requires binding of how many Ach molecules to activate?
2
Ach receptor uses a pair of alpha or beta subunits?
alpha subunits
what does ecothiophate do?
cholinesterase inhibitor
dibucaine number for normal person
80%
half life of esmolol
10-20 minutes
muscle fasciculations after succinylcholine have strongest association with which effect?
increased ICP
muscle relaxants metabolized by pseudocholinesterase
mivacurium and succinylcholine
steroid muscle relaxant that has no metabolites
rocuronium
Extubation criteria for RSBI (rapid shallow breathing index) should be less than
105 (RR/TV)
duration of neostigmine
1 hour
timing of peak effect of neostigmine
10 min
treatment for central anticholinergic syndrome
physostigmine, because its tertiary amine structure allows it to cross blood brain barrier, unlike neostigmine and edrophonium
A right to left cardiac shunt will slow the induction more in desflurane or isoflurane
desflurane because so very little desflurane is taken up so when it is further diluted with a right to left shunt, it slows induction
decreased cardiac output slows or speeds elimination of inhaled anesthetics
speeds
MAC value for ED95 for patient moving in response to surgical stimulus
1.3
which electrolyte abnormality increases MAC
hypernatremia
inhaled anesthetic that doesn’t increase apneic threshold
nitrous oxide, which also does not potentiate muscle relaxation
which of the modern inhaled anesthetics is metabolized to the greatest extent
sevoflurane, 5%
which modern inhaled anesthetic produces the greatest extent of coronary vasodilatation
isoflurane
at what MAC does isoflurane produce burst suppression of EEG
1.5 MAC
which modern inhaled anesthetic causes transient increases in sympathetic tone with rapid increases in concentration during induction
desflurane and isoflurane
desflurane can be degraded by dessicated CO2 absorbent to produce what?
carbon monoxide
A unit of insulin should decrease glucose by how much?
25 mg/dL
hypothyroidism is associated with hyper or hypo natremia?
hyponatremia because patients retain free water
Chance of cross-reaction between penicillin and cephalosporins
< 2%
why is ankylosing spondylitis patient at increased risk for neuraxial and general anesthesia?
GA: cervical neck stenosis
Neuraxial: reduced intervertebral spaces and ossification
minimum gas flow rate needed for a carbon dioxide absorber to prevent rebreathing of CO2
5L/min
least likely benefit of neuraxial anesthesia
decreased morbidity and mortality from myocardial ischemia
Neuraxial anesthesia can be done how many hrs after last dose of daily enoxaparin? And enoxaparin can be restarted how many hrs after block placed?
Block can be placed 12 hrs after last dose. Dose can be given 6 hrs after block is placed.
which epidurally given local anesthetic interferes with epidural opioid mediated analgesia
chloroprocaine
supraclavicular or interscalene block has higher incidence of transient hemidiaphragmatic paralysis
interscalene
which brachial plexus block has highest incidence of chylothorax
infraclavicular block
which brachial plexus block performed without ultrasound has highest risk of pneumothorax
infraclavicular block
axillary block likely misses what nerve and what sensory region of arm?
musculocutaneous, lateral forearm
relationship of ulnar, median, and radial nerves to the axillary artery for axillary block
ulnar is superior-medial
median is superior-lateral
radial is deep to artery
what proportion of sodium filtered by glomerulus is typically excreted in the urine
5%
Site of action of furosemide
ascending loop of Henle
ADH increases aquaporin-2 channels in what part of the nephron?
collecting duct
what part of nephron is most responsible for concentrating urine
collecting duct
what is the reason to prescribe ACE inhibitor for CHF patient?
interrupt pathological increases in sodium retention
mechanism of action of spironolactone
direct aldosterone receptor antagonist, leading to decreased Na/K ATPase activity so potassium-sparing
mechanism of action of acetazolamide
carbonic anhydrase inhibitor, leading to inhibition of bicarb uptake at proximal tubule
mechanism of action of loop diuretics
inhibit Na-K-2Cl transporter in the thick ascending limb of the loop of Henle
mechanism of action of thiazides
inhibit Na-Cl transporter in the distal convoluted tubule
furosemide’s effect on calcium level
furosemide leads to hypocalcemia
thiazide’s effect on calcium level
thiazide increase calcium reabsorption -> hypercalcemia
which is used to treat hypercalcemia? furosemide or thiazide?
furosemide
why do potassium-excreting diuretics increase risk of digoxin toxicity?
digoxin competes with potassium on Na-K ATPase, so hypokalemia worsens risk of digoxin toxicity
furosemide causes metabolic acidosis or alkalosis
metabolic alkalosis
why does a hyperosmolar state cause hyperkalemia?
Potassium follows water out of the intracellular compartment
An increased SIG (strong ion gap) demonstrates what metabolic abnormality
metabolic alkalosis
A decreased SIG (strong ion gap) demonstrates what metabolic abnormality
metabolic acidosis
Fatter or thinner people are at increased risk of ulnar neuropathy
fatter
fatter or thinner people are at increased risk of common peroneal injury
thinner
the only sure-proof way to treat “obturator reflex” in a cystoscopy under spinal anesthesia is to?
induce general anesthesia with neuromuscular blockade
What causes hyperammonemia in TURP syndrome?
glycine can be metabolized to ammonia
Transient blindness in TURP syndrome is caused by?
CNS depressing effects of glycine
What thoracic level needs to be blocked to ensure loss of sensation for a cystoscopy
T8, up to renal pelvis.
Why does cardiac output only slightly decrease with large associated increase in afterload with alpha-1 adrenergic stimulation?
stimulation of alpha-1 adrenergic receptors on myocardium leads to mild inotropy
which vasopressor is best at renal preservation in a severely septic patient with low urine output
norepinephrine
drugs of choice to treat cardiogenic shock in setting of severe acidosis
norepinephrine and dobutamine
Primary advantage of a norepinephrine gtt over a dopamine gtt for treating severe hypotension
lower rate of arrhythmias, especially high grade tachyarrhythmias
What is the end product of catecholamine metabolism?
VMA (vanillymandelic acid)
Why is dopexamine a bad drug for CHF exacerbation in setting of sepsis?
dopexamine’s effects are B2»_space;> B1 as well as potent dopamine receptor effects, which will cause worsening hypotension
how does beta 1 agonism increase lusitropy
by increasing rate of calcium uptake into sarcoplasmic reticulum during diastole. this uptake is mediated by SERCA (sarco-endoplasmic reticulum calcium ATPase)
tachyphylaxis of ephedrine is likely due to
depletion of presynaptic norepinephrine stores
beta receptors lead to a G-protein mediated stimulation of adenylate cyclase which converts ATP to?
cAMP, which ultimately leads to increased intracellular calcium concentrations
beta receptor stimulation increases intracelluluar calcium concentrations by what action?
cAMP activates protein kinase A which acts on sarcoplasmic reticulum to release calcium
Next best step for hypotensive patient with acutely failing right heart and increasing tricuspid regurgitant jet despite the absence of overt left heart failure
inhaled nitric oxide
mechanism of action of nitric oxide
stimulates guanylate cyclase which increases cGMP levels which relaxes smooth muscle which causes vasodilatation
reason for rebound hypertension following discontinuing of sodium nitroprusside treatment
increased catecholamines and renin-angiotensin release
How does nitroglycerin improve myocardial oxygen delivery to consumption ratio?
Decreased preload decreases consumption and improves perfusion. As a coronary artery dilator, it helps redistribute blood flow to subendocardium
nicardipine and hydralazine nearly exclusively dilate venous or arterial bed?
arterial bed
how do volatile agents depress myocardial contractility?
by indirectly decreasing calcium release by the sarcoplasmic reticulum
Cardiac autonomic innervation to the SA node is supplied by?
right vagus nerve and sympathetic chain that arises from T1-4 by way of stellate ganglion
cardiac autonomic innervation to the AV node is supplied by?
left vagus nerve
myocardial contractility is predictability depressed by what factors?
acidemia, anoxia, decreased sympathetic tone, and hypocalcemia
Is LVEDP increased or decreased with LV diastolic dysfunction?
Increased because a higher LVEDP is required to fill a stiff ventricle that poorly relaxes
The most sensitive and specific monitor for intraop MI is?
TEE which can demonstrate wall motion abnormalities which is the most sensitive and specific sign of ischemia
Patient who requests no sedation for cataract surgery has symptomatic episodes with slow pulse, what to do next?
consult EP
neurological outcomes after CPB is worse with pH-stat or alpha-stat strategy?
ph-stat because added CO2 causes cerebral vasodilation so small emboli are more likely to get to brain
best first line of treatment for a hypertensive patient with aortic dissection
esmolol gtt which decreases shear forces that are caused by increased heart rate and cardiac output. next line of treatment would be nicardipine or nitroprusside gtt
what type of acid/base abnormality does severe diarrhea cause?
non-gap metabolic acidosis with hypokalemia
how does thoracic epidural reduce postop ileus?
decreases sympathetic outflow to GI tract
medications that reduce lower esophageal sphincter (LES) tone
anti-cholinergics, opioids, thiopental, volatiles
What type of change in lower esophageal sphincter (LES) tone is associated with LMA use?
decrease in LES tone
gastroparesis and autonomic neuropathy are more common in T1DM or T2DM?
T1DM
propranolol decreases portal pressure by what mechanism?
Beta 2 blockade causes hepatic artery vasoconstriction which decreases liver congestion
which coagulation factors are not produced by hepatocytes?
factor III and vWB (endothelium) factor VIII (endothelium and liver sinusoidal cells)
How much of what fluid should be administered for every liter of ascites removed?
10-20 cc of 25% albumin for every liter of ascites removed
Child-Pugh score includes what components?
albumin, bilirubin, PT or INR, clinical judgment of ascites and encephalopathy
MELD score includes what components?
bilirubin, creatinine, INR
how is hepatic blood flow affected by general and neuraxial anesthesia?
hepatic blood flow decreases
the heart of a cirrhotic “high cardiac output heart failure” patient looks like?
structurally normal
what are the PA pressures in a cirrhotic patient with high cardiac output heart failure?
elevated
what is next best step when clamping IVC during liver transplant surgery causes BP to drop dramatically?
unclamp, check ABG, hct, electrolytes, volume status, and give fluids
why is hypocalcemia a sign of high risk for perioperative mortality in setting of pancreatitis?
the hypocalcemia is due to calcium precipitating with fats degraded by pancreatic enzymes. hypocalcemia also occurs in severe fat embolism and rhabdomyolysis
chance of infection with needlestick from HCV, HBV, and HIV
HBV ~ 40%
HCV ~ 2%
HIV 0.3%
what percent of patient with HCV will develop cirrhosis?
20%
type of vwD that responds to DDAVP treatment
type I
what is done to prbcs to prevent anaphylaxis in IgA deficient patients?
washing of prbcs
what is done to prbcs to prevent febrile reactions and alloimmunization
leukoreduction or leukodepletion
what is done to prbcs to prevent graft vs host disease?
irradiation of prbcs
mechanism of febrile transfusion reactions
recipient antibodies toward donor WBCs
TRALI typically resolves within how many hours?
48 hrs
most popular theory for the mechanism of TRALI
donor antibodies to HLA and other recipient antigens, also a 2-hit theory: 1) sequestration of neutrophils 2) activation of neutrophils causing a transient short lived leukopenia
transfusing a pediatric patient with 4 cc/kg of prbc will raise hemoglobin by how much?
1 g/dL
risk of HIV infection due to transfusion
1:2,000,000
risk of hep B and hep C infection due to transfusion
1:200,000
metabolic acidosis or alkalosis is often seen following massive transfusion?
metabolic alkalosis because large citrate loads is converted to bicarb in the liver
carbohydrate CO2 production for every unit of O2 consumed
1.0
protein CO2 production for every unit of O2 consumption
0.8
fat CO2 production for every unit of O2 consumption
0.7
carbonic anhydrase is primarily found where in the body?
RBCs and endothelium
Most common triggers for ARDS
pneumonia and sepsis
PaO2/FiO2 (P/F) ratio for ARDS criteria
< 200
subglottic stenosis is a risk factor when ETT is in place for how long?
> 2 weeks
gram negative or gram positive bacteria is most common in sepsis?
gram negative
Minimum NIF (negative inspiratory force) for extubation criteria
-20 to -25 cm H20
what are the two high-risk conditions that may benefit from H2 blockers to avoid stress related mucosal injury to the stomach
mechanical ventilation > 48 hrs and coagulopathy
three biggest risk factors for acalculous cholecystitis
surgery, trauma, and TPN
standard for basic anesthesia monitoring under general anesthesia includes:
oxygenation, ventilation, circulation, and temperature
natural frequency and dampening of pressure transducer are directly related or inversely related
inversely related.
10 cmH20 equates what in mmHg?
7 mmHg = 10 cmH20
what is an osborn wave?
positive deflection between QRS and ST segment, aka camel-hump sign or late delta wave, usually observed in hypothermic patients (< 32C)
carbon monoxide poisoning results in shift of oxygen-Hb dissociation curve to left or right?
left. O2 sat overestimates the PaO2.
anesthetic drug that increases amplitude and has no effect on latency for SSEP signaling
ketamine
Evoked potentials that are least sensitive to volatile agents
BAEPS (brainstem auditory evoked potentials), hearing is the last sense to be lost.
Best immediate treatment for PACU patient shivering with temp of 34.5C and new onset ST depressions
meperidine, which is faster than warmers to decrease shivering
antiseizure meds show significant reductions in seizures within how many days of a TBI (traumatic brain injury)
7 days
Best method to prevent phase I hypothermia that is due to vasodilatation and redistribution of heat from central to peripheral compartments
Pre-warming patient with forced air convection blankets prior to induction
permanent neurologic injury can result from status epilepticus after how much time?
within 5 minutes
why is status epilepticus an emergency?
sustained neuronal oxygen consumption can lead to ischemia
Postop pt in PACU has tonic/clonic seizure, what is first step?
assess and establish a patent airway
the most common cause of intraop stroke from CEA (carotidendarterectomy)
embolism, which can be caused by placing a stent
latex allergies most often occur in children with what diseases?
myelomeningocele, spina bifida, GU disease, indwelling tubes, and multiple surgeries as a child
hypothermia or hyperthermia exacerbates multiple sclerosis?
hyperthermia
Guillian-Barre syndrome (GBS) is exacerbated by what type of anesthesia?
neuraxial anesthesia, but not lumbar punctures
3 big anesthetic things to avoid in patient with myotonic dystrophy
1) succinylcholine
2) neostigmine
3) hypothermia
myasthenia gravis has 4 types, the hallmark of type I is?
isolated extraocular muscle weakness
A study showed myasthenia gravis patients undergoing thymectomy have what risks that increase likelihood of postop mechanical ventilation
1) disease duration > 6 yrs
2) vital capacity < 2.9L
3) pyridostigmine > 750 mg/day
Myasthenia gravis improves or worsens in the last trimester of pregnancy
worsens, and continues into early postpartum
Infants of myasthenia gravis mothers have transient myasthenia for how long?
about 1-3 weeks when maternal antibodies are cleared
Eaton Lambert syndrome patient’s sensitivity to muscle relaxants
increased sensitivity to both succinylcholine and nondepolarizing muscle relaxants. decreased Ach release -> increased Ach receptors
How is MAC changed with patient taking TCAs (tricyclic antidepressants)
Increased because neurotransmitter levels are increased
Use of ephedrine in a patient on TCAs (tricyclic antidepressants) will be potentiated or ineffective?
potentiated and unpredictable effect
lithium causes or treats nephrogenic diabetes insipidus?
causes nephrogenic DI
how does lithium affect muscle relaxants?
lithium potentiates both depolarizing and nondepolarizing muscle relaxants
Is lithium safe in pregnancy?
No, lithium is a teratogen
absolute contraindications to ECT (electroconvulsive therapy)
intracranial hypertension, aneurysm, and mass
best treatment for acute cocaine toxicity causing diffuse ST elevations, tachycardia, and hypertension
calcium channel blockers
drug that is most commonly abused among anesthesiologists and is most likely associated with relapse
fentanyl
what is the normal resting (end-expiration) intrapleural pressure
-5 cm H2O, this negative intrapleural pressure is always required to keep lungs from collapsing
a high Reynold’s number is consistent with turbulent or laminar flow?
turbulent flow
turbulent flow is more a function of viscosity or density?
density, turbulent flow is like ping pong balls, the more you have, the more resistance there is
Neck flexion can increase or decrease dead space
decrease
ventilatory response to hypercarbia is mediated by chemoreceptors where?
on the anterolateral surface of medulla in contact with 4th ventricular CSF
part of medullary center that is responsible for coordinating inspiration
dorsal medullary center
part of medullary center that is responsible for coordinating expiration
ventral medullary center
reason for decreased O2 saturations in a severe COPD patient after giving supplemental O2
interruption of hypoxic pulmonary vasoconstriction, leading to worsening deadspace and V/Q mismatch
why is it classic teaching to delay the second carotidendarterectomy (CEA) up to a year after the first CEA?
carotid bodies are dysfunctional (denervated) after CEA and it is assumed that it can take up to a year to return to function
what distinguishes chronic bronchitis from emphysema?
frequent cough, copious secretions, CO2 retainer earlier in disease course leading to erythrocytosis and high PA pressures and cor pulmonale
definition of very severe COPD
FEV1 < 30% or FEV1 < 50% and cor pulmonale
definition of severe COPD
FEV1 < 50% predicted
the only proven treatments to affect overall natural history of COPD
smoking cessation and O2 supplementation
best ventilation strategy for patients with noncompliant, restrictive lungs
small tidal volumes and increased respiratory rate
patient with open pneumothorax breathing spontaneously in lateral decub position, mediastinum will shift which way during inspiration?
down during inspiration and up during expiration. with mechanical ventilation, up during inspiration and down during expiration
a large pneumothorax greater than what percent of lung volume should be treated with a chest tube
> 50% of lung volume
Next best step in management of a stable patient with small pneumothorax
Repeat CXR in 3-6 hrs to rule out progression
intrathoracic lesions cause obstruction on expiration or inspiration
expiration
extrathoracic lesions cause obstruction on expiration or inspiration
inspiration
null hypothesis definition
two interventions will have the same effect
type I error is alpha or beta
alpha
false positive is type I or type II error
type I
Relationship between power and beta
power = 1 - beta
study variable that has an order and the difference between each data point is constant
interval variable
study variable that has an order but the difference between each data point is not necessarily constant
ordinal variable
study variable with no inherent ordering
nominal or categorical variable
standard deviation includes what percent of all data?
1 = 68% 2 = 95% 3 = 99%
standard deviation is a measure of what?
variance
standard error is a measure of what?
accuracy
if standard deviation is low, then the study is considered?
precise
student t-test should be used for what type of data?
continuous interval data
chi-squared test should be used for what type of data?
data that is not interval
ANOVA test should be used for what type of data?
continuous interval data for 3 or more populations
difference between student t-test and paired t-test
student t-test compares 2 different groups. paired t-test compares same group before and after an intervention
odds ratios are used when the outcome is ?
already known. relative risk is used when outcome is uncertain.
Sensitivity is calculated from 2 x 2 table with what equation?
TP / (TP + FN)
specificity is calculated from 2 x 2 table with what equation?
TN / (TN + FP)
positive predictive value is calculated from 2 x 2 table with what equation?
TP / (TP + FP), only looking at positive results of new test
negative predictive value is calculatd from 2 x 2 table with what equation?
TN / (TN + FN), only looking at negative results of new test
test’s likelihood of correctly identifying a positive result
sensitivity
test’s likelihood of correctly identifying a negative result
specificity
likelihood of a true positive being identified as a positive result by a new test
positive predictive value
likelihood of a true negative being identified as a negative result by a new test
negative predictive value
Number needed to treat (NNT) is calculated how?
NNT = 1 / ARR
ARR = absolute risk reduction
eg. risk reduces from 5% to 3%, so NNT = 1 / 2% = 50
protopathic sensation is noxious or non-noxious?
noxious (painful)
fast pain is carried by what type of fibers?
A-delta fibers
delayed, slow secondary pain is carried by what type of fibers?
C fibers
decreased pain med requirements postop after giving ketorolac is due to?
both decreased peripheral and central sensitization of pain
how are antivirals effective in treating herpes zoster?
reducing the frequency of painful zoster flares
Type of CRPS with demonstrable nerve lesions
type II
severe CRPS patients can result in what problems?
severe muscle wasting, severe osteoporosis, ankylosing joints, contractures, glossy skin
most effective early management of CRPS
series of sympathetic blocks of the affected extremity
treatment for severe longstanding CRPS
spinal cord stimulator placement, possibly ketamine
risk of CRPS is higher in women or men?
women (3:1)
what age group is CRPS most prevalent?
middle age
why avoid neuraxial anesthesia in patient with phantom limb pain (PLP)
spinal anesthesia can exacerbate symptoms
unpleasant sensation with or without a stimulus
dysesthesia
abnormal sensation without an apparent stimulus
paresthesia
perception of non-noxious sensation as pain
allodynia
pain in an area that lacks sensation
anesthesia dolorosa
increased response to a noxious stimulus
hyperalgesia
Transcutaneous electrical nerve stimulation (TENS) provides analgesia by what mechanism
stimulating large afferent epicritic fibers so original pain will no longer be as well perceived
stellate ganglion is classically blocked by locating transverse process of which cervical vertebrae?
C6
what’s the advantage of intrathecal opioid catheter vs other opioid routes for intractable cancer pain?
lower doses reduce side effects
lumbar epidural steroid injection is usually successful within how many months of an injury?
3 months, and usually takes a series of 3 injections
psychiatric disorders not correlated with chronic pain
bipolar and schizophrenia
cerebral blood flow increases only after PaO2 decreases under what value?
< 50
normal CMRO2 is about?
3.5 mL/100g/min
normal cerebral blood flow is?
50 mL/100g/min
average adult CSF volume and how much is produced a day.
150 cc, 500 cc is produced a day
What anesthesia MAC level is cerebral blood flow not autoregulated anymore
2 MAC or more
volume of venous air embolism that is lethal
> 300 cc
Hunt and Hess scale
Classify severity/mortality of subarachnoid hemorrhage: 1-minimal HA 5% 2-mod HA, nuchal rigidity 10% 3-above + drowsy 30% 4-stupor, hemiparesis 50% 5-coma,decerebrate rigidity 70%
greatest risk over the first week after a patient has a ruptured cerebral aneurysm
cerebral vasospasm
Triple H therapy for prevention and treatment of cerebral vasospasm
Hypertension (SBP > 150), Hypervolemia (CVP > 8), Hemodilution (hct 30)
Best method for monitoring for cerebral vasospasm
frequent neurochecks and transcranial doppler combined
Intracranial pressure (ICP) when risk of herniation is much higher
ICP > 30-40
isolated fractures of C1 and the occipital condyles are in general stable cervical spine injuries, true or false
true
valsalva is board code-word for?
decreased preload
handgrip maneuver is board code-word for?
increased afterload
fastest and most effective way to stabilize a CHF exacerbation with EF 35% with increased pulmonary edema
mechanical ventilation, then add lasix and pressors to treat underlying problem of volume overload
propofol induction and maintenance doses should be based on?
induction: IBW (termination is based on redistribution)
maintenance: TBW (based on clearance)
Elevated E to e’ ratio (over 15 or so) is a sign of what?
diastolic dysfunction
aldrete score includes what parameters?
activity, respiration, consciousness, circulation (blood pressure), color
Pulmonary test results that predict poor postop pneumonectomy prognosis
PaCO2 > 45, PaO2 < 50, predicted postop FEV1 of < 800 mL, FEV1/FVC < 50%, max VO2 < 10 mL/kg/min
Which is more effective? PEEP to dependent lung or CPAP to surgical lung during one lung ventilation (OLV)
CPAP to surgical lung which allows shunted blood to participate in oxygen exchange
advantages of OPCABG (off pump CABG) vs on pump CABG
decreased incidence of respiratory infections, afib, inotrope use, and fewer blood transfusions
which is the final cannula removed after CPB (cardiopulmonary bypass)
aortic cannula
mechanism of increased pulmonary artery (PA) pressures after giving protamine following cardiopulmonary bypass (CPB) surgery
thromboxane (vasoconstrictor) release from macrophages caused by heparin-protamine complexes activating complement
Best strategy to hasten rewarming after CPB (cardiopulmonary bypass) surgery
nitroglycerin (NTG) infusion
why is first degree AV block common following heart transplant?
increased refractory period of transplanted heart and slowed atrial conduction
classic presentation of digitalis toxicity
increased PVCs (bigeminy most common), anorexia, nausea. Toxicity is exacerbated by hypokalemia and hypomagnesia
beta blockers with alpha blocking properties
carvedilol and labetalol
normal umbilical artery and vein blood gases
artery: 7.3/50/20
vein: 7.35/40/30
when does fetal Hb start to be replaced by adult Hb
around 3 months, and completely at 6 months
p50 of fetal Hb
19 (27 for adult Hb)
normal neonatal glucose for full-term infant can range as low as?
30 mg/dL (< 45 mg/dL is hypoglycemia for neonates)
Concentration of dextrose used to treat hypoglycemic neonate
D10 or less
many sources advise avoidance of succinylcholine in children because?
increased risk of hyperkalemia due to undiagnosed underlying myopathies
after 28 days, respiratory distress syndrome (RDS) is called what?
bronchopulmonary dysplasia (BPD)
lecithin-sphingomyelin ratio (L/S) that is associated with fetal lung maturity
2 is sufficient surfactant production, < 1.5 is not
which muscle relaxant requires a larger dose in infants?
succinylcholine
pulse oximeter should be placed where to assess lung function of a newborn?
preductal location such as right hand
elective surgery should be delayed till what postconception age for healthy infants to reduce risk of post-anesthetic apnea
44-60 weeks (most authors favor > 50 weeks)
infant younger than 50 weeks post conception should be observed how many hours post-op to monitor post-anesthetic apnea?
12 hours after surgery (most conservative approach is 24 hr observation for infants < 60 weeks)
chest compression to ventilation ratio for neonate resuscitation
3:1
tracheal dose of epinephrine is how many times greater than IV dose?
10 times (0.1 mg/kg for tracheal, 0.01 mg/kg for IV)
congenital abdominal defect associated with other midline defects, GI, GU, and cardiac
omphalocoele, intestinal viscera herniate into base of umbilical cord and contained within membranous sac
VACTERL
V: vertebral A: anal C: cardiac T: TEF (tracheoesophageal fistula) E: esophageal atresia R: renal and radial atresia L: other limbs
how many mL/kg of packed red blood cells (prbcs) will raise hgb by 1 point
4 mL/kg
lower or higher doses of local anesthetics for neuraxial anesthesia for pregnant women
lower, they are more sensitive to local anesthetics, epidural vein congestion decreases intrathecal volume and epidural space
Preeclampsia should be considered with proteinuria levels greater than what?
above 300 mg/day
increased tidal volumes in late-term pregnancy is due to
increased anterior-posterior diameter of the chest
cardiovascular changes in pregnancy
cardiac output: 50% increase
stroke volume: 30% increase
heart rate: 15% increase
why don’t muscle relaxants cross placenta?
they are charged hydrophilic molecules
why doesn’t bupivacaine cross placenta easily?
it is highly protein bound
why do local anesthetics get trapped inside fetus?
fetal pH is lower than maternal pH, thus they become ionized and unable to cross back
latent phase of labor is primarily mediated by what spinal levels
T10-T11 (latent phase equals 0-3 cm dilation)
Nerve fibers that carry pain of active phase of labor
small visceral afferent fibers of T10-L1 which travel ALONGSIDE sympathetic nervous system
second stage of labor involves what spinal levels
pudendal nerve (S2-4) when patient is fully dilated
opioid with weak local anesthetic properties
meperidine
what’s the advantage of epinephrine in epidural infusion
marker for intravascular epidural catheter
drug with 75% effectiveness for treating a migraine
sumatriptan
reasons for emergency c-section caused by external version of breech presentation
placental abruption or umbilical cord compression
fetal scalp pH below what number is abnormal?
below 7.20, above 7.25 is normal
most common cause of preeclampsia mortality
cerebral hemorrhage
magnesium toxicity should be immediately treated how?
IV calcium
risk factors for placenta previa
prior c-section, multiparity, prior uterine surgery, and advanced maternal age
risk factors for uterine rupture
prior c-section, excess oxytocin, myomectomy,trauma, forceps delivery
most feared consequence of chronic benzodiazepine use in first trimester
cleft palate
Most cases of viral croup are due to what virus?
parainfluenza virus
treatment of croup
racemic epinephrine
why is pulmonary HTN a comorbidity in patients with severe scoliosis
restrictive lung disease causes pulmonary HTN
major complication risks of doing a wake-up test during spinal surgery
unintentional extubation, air embolism with deep inspiration
dose of epidural duramorph for pediatric patient
0.1 mg/kg
Is halothane-caffeine contracture test (HCCT) highly sensitive or highly specific?
highly sensitive
A known MH patient should be observed for how long in the PACU?
6 hours
hypothermia causes clinically significant functional coagulopathy when temp decreases to what?
33 C
intraabdominal pressure that meets definition of abdominal hypertension
12 mmHg, above 20 mmHg is associated with hypoperfusion of abdominal organs
small trials have shown pretreatment with what medication may decrease incidence of tourniquet pain?
gabapentin
afferent pathway of oculocardiac reflex involves which ganglions?
ciliary and gasserian ganglions
geniculate ganglion carries what nerve?
facial nerve
petrous ganglion carries what nerve?
glossopharyngeal nerve
jugular ganglion carries what nerves?
vagal and accessory nerves
which has quicker onset, atropine or glycopyrrolate?
atropine
Anterior spinal artery is supplied by which arteries?
Vertebral arteries superiorly. Posterior intercostal arteries in thoracic region. Artery of Adamkiewicz in lumbosacral region.
Innervation of anterior tongue
Trigeminal n., mandibular branch (V3)
