ITE block 5 Flashcards
Interval data
data has order, difference b/w values is meaningful
NO true zero exists
ex: temperature, pH
nominal data
categories w/ no order
gender, race, blood type
ordinal data
order exists, but the difference between values is not meaningful
ex: mallampati, numerical pain score
ratio data
order exists, difference between values is meaningful
TRUE zero does exist
ex: kelvin, weight, length
which types of data are categorical?
nominal, ordinal
they both kinda ordinary sounding
what types of data are numerical?
ratio, interval
ratio has a O -> so it has a true zero, interval does not
primary method of heat production in neonates
nonshivering thermogeneies
-metabolism of brown fat (uncouples oxidate phosphorylation)
Pt found down after drowning, what do you to?
always give PPV FIRST, no compressions
-b/c hypoxic so if you do compressions just moving hypoxic blood -> often oxygen from 2 breaths a start to ROSC
-also helps tx any larnygospasm
Pt found down after drowning, what do you to?
always give PPV FIRST, no compressions
-b/c hypoxic so if you do compressions just moving hypoxic blood -> often oxygen from 2 breaths a start to ROSC
-also helps tx any laryngospasm
Where does majority of cholesterol biosynthesis occur
Cytosol of hepatic cells from precursor acetyl CoA (enzyme is HMG-CoA reductase)
-why statins (HMG-CoA reductase inhibitors) prescribed to people w/ poorly controlled lipid levels
Insulin actions
-inc glucose transport into skeletal muscle and adipose tissues
inc glycogen sytnhesis and storage
inc TG synthesis
inc protein synthesis
dec glucagon release
dec lipolysis in adipose tissue
Stress resp to surgery
GH inc lipolysis and inhibits cellular glucose uptake
-surgical stress -> insulin def 2/2 opposing hormones and stress-induced insulin resistance to inc glucose available for body
neuraxial blockade and stress response
-red conc of catabolic mediators: cortisol, catecholamines
-NOT been shown to prevent secretion of cytokines pro-inflammatory: IL-2, TNF alpha, and IL 6
Implants contraindicated in MRI
cerebral aneurysm clips
ICDs
pain pumps
cochlear implants
peripheral n stimulators
any ferromagnetic-containing metal objects
Okay for MRI
spinal herrington rods
heart valve prothesis
annuloplasty rings
newer pacemakers
-okay if metal is non-ferromagnetic: Aluminum, titanium, nitinol, or stainless steel
Quenching of magnet in mRI results in for pt
massive high pressure -> if door stuck, break glass
rupture of tympanic membranes
evaluate for asphyxia and hypothermia
Therapeutic levels of Mg for preeclampsia
5-9
SE based on Mg level
> 5: deep tendon reflexes reduced
7: muscle weakness and resp depression
7-12: hypoTN
12: DTR lost, cardiac conduction abnormalities may be seen
15-20: respiratory arrest
25: asystole
Non-reassuring airway signs
-relatively long incisors
-prominent “overbite”
-pt can’t bring mandibular incisors anterior to maxillary incisors
-less than 3 cm interincisor distance
-uvula not visible when tongue protruded
-highly arched or very narrow palate
-mandibular space stiff, indurated, or has a mass
-less than 3 finger breadth
Mechanism for bradycardia that occurs w/ neonatal apnea
hypoxic stimulation of carotid chemoreceptors -> leads to inc in ventilation followed by brief apnea (hypoxic ventilatory depression)
Most important RF for apnea postop in neonates
premature birth! post-conceptual age
-highest risk: < 40 weeks PCA
-decreases b/w 40-50 weeks
-gradually declines b/w 60 weeks
Ways to dec incidence of postop apnea in neonates if risk is high
-bolus of caffeine (shown to dec incidence)
-using neuraxial techniques
-limiting opioids
Resuscitation after drowning
no pulse -> give 2 rescue breaths -> if nothing then compressions
-give it 1 min to find pulse if hypothermia b/c can have arrythmias assoc w/ it
RF that would make an invasive cardiac procedure better as opposed to medical management
-recurrent angina or ischemia at rest or w/ low level activities despite medical therapy (unstable angina)
-elevated cardiac biomarkers
-New ST depression
-signs of symp of HR or new/worsening MR
-hemodynamic instability
-sustained V tach
-PCI w/i 6 months
-prior CABG
-high risk TIMI score ( >2 points)
-red EF < 40%
TIMI score
risk stratification for rdeath and ischemic events
RF:
age > 65
> 3 CAD RF (HTN, HLD, DM, fam hx, smoker)
known CAD (stenosis > 50%)
ASA use in 7 days
severe angina (>2 episodes in 24 hours)
ECG ST changes > 0.5 mm
positive cardiac marker
0 or 1: low risk compared to higher scoroe
What type of shock is vasopressin most useful
vasodilatory (sepsis, hypothermic rewarming)
-b/c it will cause peripheral vasoconstriction, but it also dec Cardiac output (b/c inc in SVR and afterload) but raise MAP
-vasodilation at cerebral perfusion
vasopressin SE
mild dec in plt concentration and inc in plt aggregation
Allodynia
pain due to a stimulus that does not normally provoke pain
1st line for post herpetic neuralgia
gabapentin and lyrica!
albumin solutions Na conc
145 mEq/L +/- 15
Dantrolene dose for MH
2.5 mg/kg
HyperK (K > 5.9) tx
Ca chloride 10 mg/kg or Ca gluconate 10-50 mg/kg if life-threatening
-Sodium bicarb 1-2 mEq/kg
-10 units insulin
-50 cc of 50% dextrose
how do charcoal filters for MH work?
activated charcoal filter is highly porous w/ large surface area of carbon atoms that bind to volatile anesthetics
most sensitive evoked potentials to inhaled anesthetics
visual and motor evoked potentials
-visual #1
somatosensory and brainstem less sensitive
Anesthesia concern long QT syndrome
volatiles esp sevo worsen -> consider TIVA
Plateau pressure versus peak insp pressure
plateau: seen by alveoli and small airways during PPV -> static measured w/ no flow
-peak: pressure needed to deliver a breath -> result of resistance that occurs in large and medium conducting airways
When is it more reliable to weigh a cylinder to tell how much is left as opposed to using pressure?
liquified gases -> ones that exist in a pressurized cylinder at partial liquid and partial gas -> gas re-equilibrates and so pressure is full even when gas is used -> weight more accurate
-ex: nitrous oxide, propane, CO2
what gases are the pressure reliable to tell how much gas is left in a cylinder?
nonliquified gases -> so they exist entirely in gaseous form in a cylinder -> so pressure reliable indicator of how much gas left
ex: oxygen, helium, air, nitrogen
Full O2 cylinder L and psig
660L
1900 psig
Full nitrous oxide cylinder L and psig
1590L
745psig
=> pressure gauge reads full until 75% of cylinder used
Air full cylinder L and psig
625L
1900psig
Helium full cylinder L and psig
500L
1600psig
When doing biphasic shock w/ paddles directly on heart how many J?
Start at 5 -> 10 -> 20 -> 30 -> 50
Clark electrode ABG
cathode, anode, and membrane
-measures O2 on ABG, calibrated by 100% and 0% sample
-O2 passes through membrane, reduced by cathode -> creates current -> current relative to O2 sat
-C is mostly O compared to sanz and severinghaus -> so it’s the oxygen
When is an enzymatic electrode used in ABG?
Glucose concentration!
-glucose oxidase is attached to electrode -> hydrogen peroxidase that is generated by enzyme degradation creates a current that is proportional to BG concentration
Sanz electrode
measures serum pH
-sanz is shorter than severinghaus, pH is shorter than Co2
-H+ permeable membrane -> as H ions cross membrane -> generates current proportional to pH
Severinghaus electrode
measures serum CO2
-CO2 sensitive glass membrane surrounded by bicarb -> as CO2 crosses membrane ->equilibration w/ bicarb -> H ions in solution detected by electrode
-sanz is shorter than severinghaus, pH is shorter than Co2
Vaporizer output
Output = (carrier gas flow * SVP) / (barometric pressure - SVP)
Vaporizer compensation for temperature changes
10-40 C by using bimetallic strip
-it has 2 diff metals against each other that bends w/ temp changes
-when cold -> strip moves to increase the flow in, and when warm moves to decrease the flow into the vaporizer
-when you’re cold you want more heat!
Treatment of LAST
lipid emulsion 20%
1.5 cc/kg inital dose -> if doesn’t work, give it again
-then infusion .25 cc/kg/min
Nerve gas sarin MOA
AChE inhibitor -> atropine is the treatment
Difference b/w mature and immature ACh receptors
mature: at NMJ two α, and one each of β, δ, and ε subunits
immature: extrajunctinal and consists of α, β, δ, and γ subunits
Neostigmine immediately after succ
inhibits AChE, but also inhibits pseudocholinesterase -> prolong succ
What’s included in the low pressure system of an anesthesia machine w/ circle system
Flowmeters
unidirectional valves
vaporizers
pressure relief devices
hypoxia prevention safety devices
common gas outlet
To figure out how much des is needed at higher altitude
- calculate partial pressure of des = % x barometic pressure at sea level -> 5% x 760 = 38
- calculate w/ the new barometric pressure = partial pressure agent / barometric pressure -> 38 / 500 = 7.6%
Urgent warfarin reversal emergency
prothrombin complex concentrate
Fat/Blood coefficient order of inh anesthetics
Sevo (48) > iso (45) > des (27)
-needs to be considered at the end of the case to determine how long it will take to pull the gas from the fat into the blood
vessel rich group/blood solubility coefficient for inh anesthetics
iso = sevo = des = 2
CNS/blood solubility coefficient
sevo (1.7) > iso (1.5) > des (1.3)
Oil:gas solubility coefficient inh anesthestics
iso (90) > sevo (50) > DES (19)
-potency! -> b/c more hydrophobic, so needs less in CNS (b/c hydrophobic there)
thermodilution cardiac output measurement effect if injectate solution is colder than programmed injectate temp
underestimate
thermodilution cardiac output measurement effect if injectate volume is larger than programmed
understimate
Underestimation of thermodilution cardiac output
- larger volume of injectate than programmed
- colder temp of injectate volume than programmed
- large volume of fluid is administred during a reading
- self-measuring Ti probe is warmer than actual injectate temp
Overestimation of thermodilution cardiac output
- injectate bolus is smaller than programmed
2.injectate temp is warmer than programed - self measuring Ti probe is colder than actual injectate temp
OR fire triad
- Ignition source: bovie, lasers
- oxidizing agent: O2, N2O
- fuel: prep, drapes, gowns, gauze
To minimize the risk of airway fire, what changes can you make with your ETT?
Change it -> laser safe (non-PVC based) ETT
-fill ETT cuff w/ solution containing saline and methylene blue -> prevents ignition and allows easy identification of inadvertent damage
What ultrasound-guided central venous cath is a compressible, and relatively low risk of infection, thrombosis, and PTX?
Axillary
-but higher risk of brachial plexus injury
what part of the brachial plexus surrounds axillary artery
lateral, medial and posterior cord
How does heliox work?
70-30 or 80-20 helium-oxygen
-helium has a lower density than nitrogen -> converts turbulant flow to laminar flow to increase the O2 that is being delivered to alveoli
Reynolds number
Re = (density x velocity x diameter)/ viscosity
>4,000 -> flow is turbulent
< 2,300 -> flow is laminar
-so if you replace density of N w/ helium -> changes turbulent flow to laminar
Critical temperature
temperature above which a gas can no longer be converted to a liquid w/ increasing pressure alone
-ex: nitrous oxide exists in a gaseous state at standard temp and pressure -> when inc pressure and placed in E cylinder -> converted into liquid form as long as temp is less than 36.5 C
Relationship b/w resistance in airway and airway radius
R = 1/r ^ 4
-dec in airway radiance lead to exponential inc in airway resistance
Max dose of lido w and w/o epi
w/o: 4.5 mg/kg
w/ epi: 7 mg/kg
max dose of bupivacaine w and w/o epi
both: 2.5 mg/kg
What determines local anesthetic potency
lipid solubility -> more solubility crosses membrane faster -> enhanced diffusion through n sheaths
What determines local anesthetic time to onset
pKa -> determines ionized v unionzed form -> can only cross when unionized
What determines local anesthetic duration of action
protein binding
-highly protein bound will remain bound for longer
What determines local anesthetic level of absorption
Location of injection
BICEPSS
IV (blood) > intercostal > caudal > epidural > brachial Plexus > Sciatic > subcutaneous
Alveolar gas equation
used to calculated the partial pressure of oxygen in alveoli in lungs
PAO2 = FiO2 x (Patm - PH2O) - (PaCO2/RQ)
-used to determine PAO2 for A-a gradient
Normal A-a gradient
< 10
-higher indicates ventilation/perfusion issue
Anesthesia dolorosa
pain is invoked a region that is denervated and should not have sensation at all
-pain referral phenomenon
2 hrs after 2U of pRBCs, acutely febrile, hypoxic, chills, pink frothy airway secretions, CXR pulm infiltates
TRALI
-supportive care -> give O2, intubate if needed
-symp usually w/i 6 hrs of transfusion
**separates from acute hemolytic which would happen in MINUTES*
Cause of TRALI
Donor antibodies attack recipient neutrophils -> attack pulm vasculature -> pulm edema
blood transfusion after: HTN, dyspnea, tachycardia, CXR b/l infiltrates
TACO
-give diuretics
Tx for organophosphate poisoning
atropine and pralidoxime (also does nicotinic receptors! w/i first 48 hrs)
Dimercaprol
used for toxicity involving arsenic, mercury or gold
-tx for Wilson dx
What hypersensitivity type of allergy is latex allergy?
Type I
IgE -> urticaria, bronchospasm, anaphylaxis
difference b/w skin reactions in Type I and type IV hypersensitivty reactions
type I: hives, immediately occurs after exposure
type IV: delayed T-cell mediated, appears 1-4 days after contact -> appears like eczema w/ vesciles -> lichenified, dry, crusted
Type II hypersensitivity reaction
IgG or IgM antibodies formed against previously exposed anitgens
ex: Graves and myasthenia gravis
Type III hypersentivity
Antigen IgG complexes -> deposited in tissues -> activation of complement cascade and inflammation
-ex: serum sickness, lupus nephritis
What food allergies are assoc w/ latex allergy?
avocados, apple, bananas, buckwheat, carrot, celery, chestnut, kiwis, melon, papaya, peach, pineapple, tomatoes, and white potatoes
Normal central venous pressure waveform
affect of a fib on CVP waveform
loss of a wave
affect of AV dissociation on CVP waveform
cannon a waves
effect of tricuspid regurge on CVP waveform
tall, fused c and v waves, loss of x descent
effect of tricuspid stenosis on CVP waveform
tall a and v waves, minimal y descent
RV ischemia on CVP waveform
tall a and v waves
steep x and y descents
“M or W” configuration
pericardial constriction on CVP waveform
tall a and v waves
steep x an y descents
M or W configuration
cardiac tamponade on CVP waveform
dominant x descent, minimal y
Sacubitril
anti-HTN that acts by inh enzyme neprilysin (enzyme that breaks down ANP and BNP)
Main receptors on plts
adenosine diphosphate (ADP)
thrombin
thromboxane A2 (TXA2)
glycoprotein IIb receptor (binds vWF)
plt process after bound to damaged epithelial cell
once bound to damaged epithelial a change in shape happens ->alters receptors on surface so can be activated -> glycoprotein IIb/IIIa receptor is more prominent allowing binding of fibrinogen -> formation of bridge where other plts bind
-plts become negatively charged -> allowing factor V to bind (cofactor for thrombin)
ASA MOA and duration
COX enzyme inhibitor
-COX allows conversion of arachidonic acid to PG -> TXA2 (vital for plt aggregation and vasoconstriction)
-irreversible, so plt lifespan 5-10 days
Clopidogrel and prasugrel
thienopyridines -> plt receptor inhibitors
-selectively inhibit ADP-induced plt aggregation
-form a covalent bond to P2Y12 receptor -> unresponsive to ADP -> irreversible
*prodrug -> large amount of interpt variability
Ticagrelor
cyclopentyl-triazolo-pryimidines
ADP analog -> P2Y12 receptor antagonist -> reversible block
-not a prodrug -> less inter-pt variability
Cangrelor
Purinoreceptor anatogonist -> IV P2Y12 rec antagonist
-short 1/2 life and plasma clearance -> 70% plts normal after 1 hr stopping infusion
Abciximab, Eptifibtaide, tirofiban
Glycoprotein IIb/IIIa antagonists
-used in acute MI where cath or PCI is planned
-monitored by plt aggregometry, no change in PT/PTT
DAPT in drug eluding stent and elective surgery
6-12 months elective
3 months minimum if delaying would result in significant morbidity
surgery after balloon angioplasty
surgery can occur 2 weeks after procedure
-do not need DAPT after, may benefit from antiplt for stroke or MI prevention
Surgery post CABG
can have additional surgery as soon as they are healed, do not a specific amount of time, can proceed w/i 1 week if needed
-if can wait, allow time for a full recovery
DAPT bare metal stents
at least 1 month
late decelerations on OB
uteroplacental blood flow problem
Intrauterine resuscitative efforts before c/s in nonemergent situations
L lateral decubitus positioning
Supplemental O2
turn off oxytocin
fluids/vasopressors if hypoTN
Decrease the risk of hypoglycemia after TPN d/c
use lower glucose-to-lipid ratio TPN -> makes less insulin
start IV glucose after d/c w/ freq glucose checks
turn off IV insulin
Refeeding syndrome
fluids and electrolyte issues (hypoPhos) after starting TPN w/ poor or no nutritional intake for > 72-96 hrs
*higher risk if low prealbumin <10)
Static compliance
statis compl = TV/(plateau P - PEEP)
change in volume/change in pressure
elastic resistance
Dynamic compliacen
continous measure of compliance as pt breaths
-elastic and airway resistance
Massive Transfusion
Given at least 10 units of blood products w/i a 24 hour period
When to give plts in MTP
if plts < 75,000
could be dilutional or DIC
Cryoprecipitate contents
factor VIII, fibrinogen, vWF, and fibronectin
Indications for cryo
- microvascular w/ fibrnogen < 80-100
- hemorrhage or massive transfusion w/ fibrniogen < 100-150
- ppx in hemophilia A and vWD
The difference in success and injury b/w video-assisted laryngoscope compared to DL
VL has more seriously peri0intubation complications than DL
-no improvment in 1st pass success w/ DL
-higher rate of life-threatening complications w/ DL
-NO change in risk of pharyngeal injury
Possible complications of mask ventilation
direct pressure trauma from improperly fitting mask
lifting pressure to mandible -> subluxation of TMJ
Acid/base status of large amount of blood transfusions
Metabolic alkalosis -> citrate metabolized to bicarb
what is citrate metabolized by
the liver
no prior hx of HTN at 24 wks gestation, 145/95 then 1 week later 150/100, 24 hr urine shows 25 mg of protein, asymp, labs normal dx?
gestational HTN
-to meet preeclampsia dx proteinuria: >300 mg/24 hrs, protein-cr ratio > 0.3 or 1+ on urine dipstick
Diff b/w preeclampsia w/ and w/o severe features
w/o: HTN + proteinuria
w/: HTN, proteinuria plus epigastric or RUQ pain, fetal growth restriction, BP > 160 or diastolic > 110, plts < 100, in Cr, inc LFTs, pulm edema, visual changes, neuro changes
Anesthesia considerations for AVM repair
-hypoTN during actual embolization -> slow flow through AVM and prevent embolization of occlusive material
-can be done under MA or GA
-AC for 1st 24 hrs to prevent occlusion near embolization
Normal perfusion pressure breakthrough
After AVM occlusion -> prev brain was max dilated b/c used to high flow low P system of AVM
-after closure -> normal perfusion pressure results in excessive CBF and hyperemia -> brain edema and hemorrhage
Succ and neonate dosing
higher doses needed for inc volume of distribtuion -> but avoid succ when you can due to possibility of undx dystrophies
mature v immature ACh receptors, how much longer is the immature open
10x inc in ion channel opening times
How long does it take to start upregulation of immature fetal nicotinic ACh receptors in pts who are immobile?
w/i 72 hours
The fastest way to reverse a suspected high spinal
CSF lavage: removal 20cc of CSF and replace w/ sterile normal saline or plasmalyte
**lipid emulsion doesn’t help, because it’s not LAST
Hemophilia A
X-linked def factor VIII
-aPTT prolonged and PT is normal
-1st line tx: Desmopressin if minor, if active bleeding: Cryo
Pt w/ hx of hemophilia A hx of prior MTP, what to give pt if large intraop blood loss refractory to cryoprecipitate
Recombinant factor VIIa and IIa
-pts who have a large amount of blood transfuionsn may get antibodies to exogenous human factor VIIIa
-tx: porcine factor VIII, recombinant factor VIIa, or recombinant factor IIa -> since VIIa is extrinsic pathway, and IIa is further down on both pathways
Neonatal myasthenia gravis
20% of infants if moms have it
-if mom has 1st child w/ it, likelihoood of 2nd child having it are 75%
-Neostigmine can help w/ weakness prior to feeding
-symp should be gone by 4 weeks
SVT in pregnant women tx?
Adenosine 1st line after attempting vagal maneuvers
Best method of preoxygenation to prolong apnea time
breathing 100% O2 until EtO2 >90%
-usually 3-5 min of TV breathing 100% O2 at 10-12 L/min FGF
Normal murmur v abnormal in preg
normal: systolic murmur grade 1 or 2 flow murmur
abnormal: diastolic murmur, or grade 3/4 systolic murmur
Normal aortic valve area
3-4 cm^2
-symptoms usually start when valve area <1 and pressure gradient > 40
aortic valve area and gradient in pregnant pts w/ high risk for CV complications
area < 1-1.5
gradient 25-50
Which pts most likely to get arrhythmias while pregnant
congenital heart dx pts s/p fontan procedure
P50 Hg curve
the O2 tension when SaO2 is 50%
normal: 27
L shift -> lower P50 valuve
R shift -> higher P50 value
What causes an inc in 23DPG -> R shift of Hg curve
Thyroxine
Hyperphos
Anemia
Altitude sickness
CHF
liver cirrhosis
sleep apnea syndrome
Stored RBCs and Hg curve
Decreased 2,3DPG, L shift
Absolute CI to trach placement
operator inexperience
infants (esp w/ congenital anatomy issues tracheomalacia, tracheal stenosis)
insertion site infection
severe/uncontrolled coagulpathy
unstable cervical spine
percutaneous tracheostomy
put a guidewire through small opening into trachea -> serial dilation -> tracheostomy tube over wire
Most likely to attenuate some of the effects of radiation exposure
potassium iodide -> saturate the thyroid with this iodide so it doesn’t uptake the radioactive I
w/i 24 hrs of exposure
How to decide who gets a TAVR
-if they have a high-risk medicial condition that they would not do well w/ surgical fix
-but must have a life expectancy of > 1 year where benefits of TAVR > risks
-must have symptomatic AS
-if low risk -> get surgical replacement
How to handle symp epiglottitis in peds
Take to OR -> inhalation induction, no muscle relaxants -> perform intubation under GA
Stage II in inhalational induction in adults
usually avoided w/ high conc of sevo that are being used to induce adult pts
Plasma osmolarity
Osmolarity = (2xNa) + (glucose/18) + (BUN/2.8)
What fluid will dec serum osmolality
Plasmalyte
Why avoid lactated ringers in liver failure?
Lactate normally broken down to bicarb -> won’t happen in liver failure
Retained epidural catheter tip pt asymp next step?
observation
pt spontaneous muscle hematoma, no family hx of coag issues, PTT high, stays high after mixing study, plts and fibrinogen normal, dx?
Antibody inhibitor to a coagulation factor (MC acquired hemophilia A, inhibitor to factor VIII)
-assoc w/ Autoimmune d/o (type 1 DM, SLE, rheumatoid arthritis), malignancy, or recent birth
-the mixing study tells all the difference b/w if it was hemophilia A, she would have a family hx (less likely in women b/c X linked), and would be fixed by mixing study
Prolonged bleeding time w/ epistaxis, menorrhagia, prolonged bleeding after dental extractions
vWD
What causes more problems: aspirated roasted or unraosted peanuts?
Unroasted: the oils cause more pnuemonitis
-both bad b/c likely to crumble and cause more obstructions further down in tree
End of diagnostic lap, inc EtCO2, pulse ox stable, airway pressure stable, dx?
Subcutaneous emphysema
Abd compartment syndrome sacle
grade 1: P 10-15
2: 16-25
3: 26-35
4: > 35
Dec PaCO2 by 1, what happens to CBF
Dec by 1-2 cc/100g/min
A patient who has the capacity to understand the consequences to reject or accept medical tx is…
Autonomy
*informed consent is part of this
Obligation of physicians to do good for their pts
Beneficence
Physician Obligation to do no harm
Nonmaleficence
A new treatment should be given equally across all societal groups, which doctor obligation?
Justice
Inc Pulm Vascular Reistance
pain
hypothermia
acidosis
hypercarbia
nitrous oxide
Anesthesia induction concerns w/ tetralogy of Fallot
prevent R -> L shunt
use katmine as an inducer to prevent dec of SVR -> if SVR < PVR => R to L shunt
-if you get hypoxia and hypoTN, put pressure on abd of raise legs to inc preoad and dec afterload
When can you use neostigmine to reverse succinylcholine apnea
in a phase II block (in pt w/ abnormal pseudocholinesterase 60-120 min after dose)
TOF < 0.3 w/ fade
-use 0.3 mg/kg -> any larger will cause inhibition of pseudocholinesterase as well and succ won’t break down
**however, safest to confinut emechanical ventilation until muscle tone returns
Dibucaine number
Determine if pseudocholinesterase def
-if low the natural enzyme is not inhibited by dibucaine -> abnormal
Normal: 70-80
Heterozygous: 50-60
Homozygous: 20-30
Pulm Pathophysiology of Drowning
Hold breath voluntarily -> larygnospasm -> hypoxia to point of unable to hold laryngospasm -> aspiration
-pulm issues due to washout of surfactant -> V?W mismatch -> hypoxemia
*if you survive do not aspiration enough water to make a change in blood volume!
MOA of NG on uterine smooth muscle
converted to nitric oxide -> diffuses to activate guanylyl cyclase -> inc cGMP -> sequestration of Calcium -> smooth m relaxation
MOA of phosphodiesterase 5 inhibitors
potentiate the actions of nitrates -> prolongation of cGMP
Which factors decrease during storage of FFP?
VIII and V -> why not helpful in treating hemophilia A
Why cryo over FFP to tx hemophilia A
higher conc of factor VIII
Why does FFP help w/ heparin resistance?
FFP containsf ATIII
Stage II excitation in adult inhalation induction
Generally avoided b/c of the high conc of sevo used for induction of adults
MEPs v SSEPs which better for detecting spinal cord ischemia?
MEPs -> SSEPs are slower response and have a higher false positive and false negative rate
MEP changes that correlate to spinal cord ischemia
MEP ratio of adductor pollicis to anterior tibial reduction > 50% or latency dec > 10%
Which do volatiles affect more MEPs or SSEPs
volatiles supress MEPs to a signifacntly greater degree
During spine surgery, which nerve is most commonly monitored of ischemia?
tibial nerve
Nociceptive afferent neurons
made of A delta and C fibers
-high threshold
-A delta: thinly myelinated, C: slow-conducting unmyelinated
Metabolism of inhaled anesthetics
Des, iso, and sevo metab by cytochrome P450 2E1 into inorganic fluoride in kidneys and liver
Sevo»_space; iso > des
What is soda lime?
CO2 absorber
80% calcium hydroxide
15% water
4% sodium hydroxide
-> greater CO2 absorption than Ca hydroxide or barium hydroxide alone b/c of inc water content
Desiccated CO2 absorbents w/ sevo and des
sevo produces most heat
des produces most CO
Calcium hydroxide absorbents
lack strong bases -> offer less CO2 absorption
-but less risk of fire or compound A production
Barium hydroxide absorbents
most likely to produce compound A and be assoc w/ fire production
-when combines w/ CO2 creates more heat than soda lime
why its removed from US market
Ethyl violet
pH indicator used in CO2 absorbents which becomes purple when pH < 10.3 -> absorbent exhaustion
2 hours after 2U pRBCs, desat to 88%, chills, pink forthy airway secretions, pulm infiltrates on CXR, dx? tx?
TRALI
supportive -> give O2, intubate if needed, ARDS protocol for vent
MOA of nitrous oxide
noncompetitive inhibition of NMDA receptors 2
-analgesic: release of endogenous opioids or weak direct agonism
Nitrous oxide hemodynamic changes
-may cause myocardial depression, but stimulations symp NS to inc systemic vascular resistsance and inc cardiac output
-dec TV, inc RR, no change on MV
-inc CBF and ICP
What is the highest risk of inc the risk of postop A fib?
Hypovolemia -> b/c dec volume, dec O2 delivery, inc catecholamines -> inc risk
Hypervolemia -> inc atrial stretch, inc in atrial cell triggering
Inc risk of postop A fib
male sex
hypo/hypervolemia
surgery type: inc risk in cardiac and major thoracic
hx of a fib
obesity
asthma/COPD
atrial injury
ischemia, inflammation
electrolyte disturbances
adv age
HTN
valvular dx
fetus: what age is pulm system mature for adequate gas exchange?
24-26 weeks
neonate: how long does it take for the fluid-filled alveoli to expand and become air filled?
5-10 minutes of life
neonate: what initial negative intrathoracic pressure is required to expand alveoli?
40-60 cm H2O
neonate: how long does it take to reach a normal RBC?
10-20 minutes of life
-inc in PaO2 and dec in PaCO2
Morquio syndrome
Auto Rec lysosomal storage d/o
-short-trunk dwarfism, corneal deposits, normal intelligence, odontoid hypoplasisa w/ atlantoaxial instability
**risk of SC damage w/ DL
What factor is protective against preeclampsia?
smoking
ppx therapy for preeclampsia
low dose aspirin
RF for preeclampsia
Antiphospholipid syndrome
prior preeclampsia
chronic HTN
DM
obesity
assisted reproductive techniques
To maintain professional standing MOCA w/ ABA:
-maintain an active license to practice medicine in Canada or US
-Any restrictions on the license must be reported to ABA w/i 60 days
Original purpose of developing ASA physical status classification system
comparison of anesthetic data
Protective traits for peds preop anxiety
Enrollment in daycare
calm temperament
high number of siblings
-age >5 and not anxious parents help
Inc risk of peds preop anxiety
parental divorce
age 1-5
hx of poor medical encounters
children of anxious parents
lower educational background of parents
Primary adrenal insuff labs
hyperK, hypoNa, hypoglycemia, hyperCa
What happens if you put iso in a sevo vaporizer?
iso has a higher saturated vapor pressure -> larger amt of it in gas form, so when FGF comes in, picks up more iso -> higher % than on dial
RF for getting a vascular or cardiac perforation w/ removal of an ICD/PM lead
> 5 years since placement of ICD
female
BMI < 25 (lower BMI, female have smaller blood vessels)
ICD leads > PM leads (ICD leads larger so more scar tissue)
Reasons an ICD/PM would be removed
recall
lead fracture causing malfunction or arrhythmias
infxn
thrombotic complication
What passes easily across BBB?
lipophilic small molecules (O2, CO2)
Timing of amniotic fluid embolism
during or w/i 30 minute sof labor, c/s, D&C or postpartum
Symp of Amniotic fluid embolism
1st phase: severe pulm vasospasm -> R heart failure
2nd phase: LV failure, consumptive coagulopathy, pulm edema, R heart relaxes, uterine hypertonus -> fetal bradycardia and distress
-if pt non postpartum -> 911 c/s
Renal changes w/ hypothermia
renal tubules dysfxn -> inc UOP -> cold diuresis
Glucose and hypothermia
hyperglycemia -> dec insulin
ABG in hypothermia
PaCO2 and PaO2 dec, pH inc
CV hypothermia
low cardiac output and bradycardia
-inc risk for arrythmias
-defib ineffective if temp < 30
-SVR inc
Best mapleson for spontaneous vent
most efficient FGF: A
AS expected: A for spontaneous
Best mapleson for controlled vent
D
CD in alphabet: Controlled D
worse pain w/ lumbar spine extension and axial rotation
facet arthropathy
low back pain, worse on one side, can radiate to posterior buttock and thigh of affected side
Sacroiliac joint dysfxn
-hip flexion/abduction/external rotation, pelvis compression brings it out
worsening pain and possible lower extremity weakness that is worse when walking down the hill
spinal stenosis
“shopping cart sign”
What back issue is relieved w/ extension and worse w/ flexion
radiculopathy (herniated disc compressing nerve)
painful, reproducible spasticity on palpation
muscle strain
treatment of autoimmune thrombocytopenic purpura in pregnancy
caused by Ab to plts -> spleen eats them
-give steroids if plts < 50k in labor, <30k in pregnancy
-if no luck, IVIG
Limit of plts for neuraxial/ catheter removal
80k
toxicity of tacrolimus
nephrotoxicity
toxicity of methotrexate
pulm, hepatic, thyroid, myelosuppression
Lyte changes in acute small bowel obstruction w/ severe N/V
due to large amt of gastric fluid loss -> hypoNa, hypoK, hypovolemia
-met acidosis more common b/c of loss of luids -> lactic acidosis from tissue ischemia, dehydration, starvation, ketosis
hemodynamic change sw/ severe abd obstruction
hypovolemic from severe N/V
dec FRC (abd distention) -> limiting downward movement -> inc if PaCO2 and dec PaO2
-impaired venous return (can’t get as neg intrathoracic pressure and direct vena cava compression)
Cohort study
When exposure and outcomes occur before study begins
-if you look at PONV pts and see if they had exposure to multivitamins or not
-see if exposure plays a role in outcome of interest
case-control study
pt selected w/ outcome as case gropu, w/o outcome as control group -> see what % has been exposed and not exposed
-usually used in rare dx or dx w/ long latent periods
