**New New TrueLearn Deck** Flashcards
how does calcium work in the treatment of hyperkalemia?
antagonist of potassium and temporarily stabilizes the myocardium
which treatment for hyperkalemia is effective almost immediately?
calcium
which inhalational anesthetic is associated with megaloblastic hematologic changes and by what mechanism?
nitrous oxide
- decreases vitamin B12 dependent enzyme activity (methionine synthetase and thymidylate synthetase)
precedex respiratory effects?
- preserves respiratory drive
- does NOT decrease ventilatory response to hypercapnia
- NO change in respiratory rate but decreases tidal volume, so decreases minute ventilation
precedex cerebral effects?
decreases BOTH cerebral blood flow and cerebral metabolic rate of oxygen
which anticholinergic agent does NOT have CNS penetration?
glycopyrrolate
glycopyrrolate duration of action?
2-4 hours
neostigmine duration of action?
20-30 min
atropine duration of action?
15-30 min
glycopyrrolate onset of action?
1 min
neostigmine onset of action?
1 min
atropine onset of action?
1 min
pyridostigmine duration of action?
6 hrs
pyridostigmine onset of action?
> 15-20 min
which opioid has the fastest onset of action?
alfentanil
how does large volumes of NS affect potassium levels?
the acidosis causes hyperkalemia due to H+/K+ exchange
Which effect explains the oxygen release and dissociation from Hb?
Bohr effect
Which effect explains the carbon dioxide release and dissociation from Hb?
Haldane effect
how is mivacurium metabolized?
mivacurium is metabolized by plasma cholinesterase (butyrylcholinesterase) through hydrolysis. This rapid breakdown leads to a short duration of action compared to other nondepolarizing neuromuscular blockers.
which drugs are excreted by the kidneys?
morphine and meperidine
the accumulation of active metabolite of which drug causes seizures?
meperidine
what is morphine’s active metabolite and its effects?
morphine-6-glucuronide (M6G) has increased potency and can lead to respiratory depression in renal failure due to delayed excretion
what is morphine’s inactive metabolite and its effects?
morphine-3-glucuronide (M3G) can cause myoclonus and allodynia
for a-line, which artery lacks collateral blood flow?
brachial artery
for a-line, which artery has collateral blood flow?
radial artery (from ulnar artery)
for a-line, which artery is near a nerve (and which one)?
median nerve is just medial to brachial artery
in which condition is an ACE inhibitor contraindicated?
pregnancy (teratogenic)
_____ ischemic optic neuropathy is distinguished by this feature
anterior; optic disc edema or pallor
nitroglycerin vascular effects
pure venous vasodilator; decreases preload
nitroprusside vascular effects
balanced arteriolar and venous vasodilator; decreases both preload and afterload
how does high altitude affect MAC of desflurane?
pt receives LESS of the MAC compared to sea level
which diuretic acts on the proximal convoluted tubule?
acetazolamide
which diuretic acts on the thick descending loop of Henle?
mannitol
which diuretic acts on the thick ascending loop of Henle?
bumetanide, furosemide, ethacrynic acid
which diuretic acts on the distal convoluted tubule?
thiazide, metolazone
which diuretic acts on the collecting duct?
spironolactone, amiloride, triamterene
how does lower temperature affect blood gas sample pH, PaCO2, and PaO2?
higher pH, lower PaCO2, and lower PaO2
how is 2-chloroprocaine metabolized?
Ester local anesthetics are a class of local anesthetics that are metabolized by plasma cholinesterases (pseudocholinesterases) rather than the liver. They typically have a shorter duration of action compared to amide local anesthetics and have a higher likelihood of causing allergic reactions due to their metabolism into para-aminobenzoic acid (PABA), a known allergen.
how to differentiate local anesthetics?
One ‘i’ in ester, two ‘i’s in amide”
Ester anesthetics (e.g., procaine, tetracaine) have one ‘i’ in their name.
Amide anesthetics (e.g., lidocaine, bupivacaine) have two ‘i’s in their name.
what is a relative contraindication to transtracheal jet ventilation?
COPD, due to air trapping
what is an absolute contraindication to transtracheal jet ventilation?
severe tracheal stenosis and complete upper airway obstruction
which nephron segment accounts for the majority of sodium reabsorption?
proximal tubule
how is atenolol metabolized and excreted?
Atenolol is primarily excreted unchanged by the kidneys and undergoes minimal metabolism in the liver.
The drug’s half-life increases significantly in renal impairment since it relies heavily on kidney function for elimination.
Dose adjustments are necessary in patients with renal impairment to avoid drug accumulation and excessive beta-blockade.
how is epidural spread of local anesthetic affected by age?
spread is greater in elderly pts, compliance of epidural space is decreased, so the space will expand less
which factor affects epidural spread of local anesthetic the most?
volume
how does NS affect strong ion difference?
decreases, because normal plasma has SID of around 40, whereas NaCl is 0, so brings it closer to 0
difference between older vs. newer carbon dioxide absorbents?
newer absorbents lack strong bases and produce less carbon monoxide
how do pH and temperature affect the speed of the Hofmann elimination?
increased pH and temp increases reaction speed
how does cisatracurium/atracurium undergo metabolism?
Hoffmann elimination, not catalyzed by an enzyme, independent of renal or hepatic function
excessive fasciculation from succinylcholine would occur in which condition and why?
myotonic dystrophy, due to impaired muscle relaxation, ventilation and intubation can become challenging
when should amiodarone be considered during ACLS?
if pt continues to have v-fib despite prolonged CPR and rounds of epi and defibrillation
which neurological structure is the primary efferent pathway for the hippocampus?
fornix
what is the initial substrate for anaerobic glycolysis?
pyruvate
chronic corticosteroid therapy causes which electrolyte abnormalities and why?
increased urinary calcium due to inhibition of intestinal calcium absorption
chronic corticosteroid therapy effect on RBC count?
increases Hgb concentration
ginseng effects?
hypoglycemia
what happens within a day of smoking cessation?
rightward shift of hemoglobin P50 curve; improved oxygen delivery to tissues
how does cigarette smoke affect the hemoglobin dissociation curve?
the carbon monoxide in cigarette smoke causes a leftward shift in the P50 of hemoglobin
what happens within 48-72 hours of smoking cessation?
increased secretions and a more reactive airway
what happens within 2-4 weeks of smoking cessation?
decreased secretions and less reactive airway
which drug used to treat hyperkalemia has the slowest onset of action?
patiromer - oral potassium binder with effects evident after 7 hours
which subunit is present only in junctional receptors and not in extrajunctional receptors?
epsilon subunit
what is the function of citrate as an additive in RBCs?
anticoagulant
which additive in RBCs is used as a buffer?
phosphate
propofol effects on respiratory sytem?
- causes bronchodilation and airway smooth muscle relaxation
- potentiates hypoxic vasoconstriction
how is the NMDA receptor activated?
both of the following conditions must be met for the NMDA receptor to become activated:
- Glutamate (or glycine) must be bound (ligand-gated)
- The cell must be depolarized (voltage-gated)
The receptor will not be active if only one of these conditions is met.
what is the primary mediator of the effects of NMDA receptor activation?
increased intracellular calcium
ginkgo effects?
inhibits platelet-activating factor, which increases bleeding
kava effects?
increases sedation
unpaired t-test?
compares two separate, independent groups
paired t-test?
compares same group, pre- vs post-intervention
BMI ____ is a risk factor for difficult bag mask ventilation
> 26
mouth opening ____ is a risk factor for difficult bag mask ventilation
<3 cm
thyromental distance ____ is a risk factor for difficult bag mask ventilation
<6 cm
what is a treatment for central anticholinergic syndrome and why?
physostigmine, crosses the blood-brain barrier
cricothyroid function
tenses vocal cords
posterior cricoarytenoid function
abducts vocal cords
thyroarytenoid function
relaxes vocal cords
lateral cricoarytenoid function
adducts vocal cords
transverse and oblique arytenoids function
adducts vocal cords
cricothyroid unilateral injury effect
minimal effect
cricothyroid bilateral injury effect
hoarseness, tiring of voice
mechanism by which insulin lowers potassium?
insulin increases the activity of the Na-K ATPase pump
which epidural opioid produces the longest duration of analgesic effect?
morphine
this is why large doses of epidural morphine are not recommended bc of the increased risk of delayed respiratory depression even after an epidural is removed
which subunit is unique to the immature extrajunctional ACh receptors?
gamma
how do PPIs affect antiplatelet drugs?
decrease clopidogrel efficacy
which IV fluid has the highest osmolarity?
0.9% normal saline
what is phase I reaction of the liver?
converts a lipophilic drug into a hydrophilic molecule through reduction, oxidation, and hydrolysis
what is phase III reaction of the liver?
Transport and Excretion
what is phase II reaction of the liver?
conjugations of the products of phase I. glucuronidation in which gluconic acid is conjugated to the drug
which phase of the liver metabolism uses P450?
Phase I
how does phenobarbital affect P450?
induces it
how do colloids such as dextrans affect thrombosis?
they have an antithrombotic effect that results in the inhibition of platelet aggregation
thiazide mechanism of action and where?
distal convoluted tubule - thiazide-induced blockade of Na+ entry enhances Na+/Ca2+ antiporter (on the other side of membrane)
how do NSAIDS affect hemostasis?
decreases hemostasis -> GI hemorrhage
thyromental distance less than ______ is predictive of difficult laryngoscopy
3 fingerbreadths, or less than 6.5 cm
where are benzodiazepines metabolized?
liver
where and how is propofol metabolized?
liver
very high hepatic extraction ratio i.e. almost all of the propofol that reaches the liver by the hepatic artery or the portal vein will be metabolized, and the concentration in the hepatic veins will be near zero.
how is propofol affected by liver enzyme induction and why?
unaffected because liver is already metabolizing 100% of the drug it receives, enzymatic induction will not further increase it
how is propofol affected by liver disease and why?
unaffected because the capacity of the liver is so high that even a half functional liver can still metabolize all of the drug it receives
how is propofol clearance affected by changes in hepatic blood flow?
decreased cardiac output and decreased hepatic blood flow will cause decreased propofol clearance because a high hepatic extraction ratio makes propofol sensitive to changes in hepatic blood flow
which drugs is neuroleptic malignant syndrome caused by?
antipsychotics like haldol, newer atypical antipsychotics
buprenorphine action on receptors?
mu-opioid partial agonist (with ceiling effect especially for respiratory depression) and k-opioid antagonist
which medication should be avoided in pregnancy?
benzodiazepines
etomidate, propofol, and rocuronium are all fine
Gay-Lussac’s Law
the pressure of a fixed amount of gas is directly proportional to its absolute temperature when the volume remains constant
P1/T1=P2/T2
what enzymatic action on synapsin proteins results in ACh vesicle fusion?
phosphorylation
Boyle’s Law
PV=PV
Charles Law
VT=VT
dibucaine number for normal pseudocholinesterase
80
homozygote for the most common abnormal allele of pseudocholinesterase will have a dibucaine number of…
20
atypical heterozygote has dibucaine number ____ with prolonged duration of action for succinylcholine
50-60
what are the shockable rhythms during cardiac arrest?
v-fib and v-tach
what are non-shockable rhythms during cardiac arrest?
asystole and PEA
which drugs have an additive effect?
inhaled anesthetics
what effect does remifentanil have on the BIS?
no effect
opioids do not affect the BIS value
sodium bicarb effect on local anesthetic
faster diffusion, so faster onset.
more rapid and complete sensory block
what is moderate sedation characterized by
verbal or tactile stimulation causes purposeful response
what is deep sedation characterized by
repeated or painful stimulation causes purposeful response
what is general anesthesia characterized by
unarousable with painful stimulus
what is the metabolite of morphine that accumulates in patients with renal failure and causes increased seizure potential
morphine-3-glucuronide (M3G)
what are the metabolites of morphine and their effects
Two major metabolites are formed:
- Morphine-6-glucuronide (M6G) – active metabolite with analgesic properties.
- Morphine-3-glucuronide (M3G) – lacks analgesic effects but has neurotoxic effects.
M3G accumulation in renal impairment can lead to seizures, myoclonus, and neuroexcitation.
This is why morphine is generally avoided or used with extreme caution in patients with significant renal failure.
Fentanyl and hydromorphone are preferred because they have minimal active metabolites that accumulate in renal failure.
where and how is morphine metabolized
Morphine is metabolized in the liver primarily via glucuronidation
what is the metabolite of meperidine and its effect
normeperidine, increases potential for causing seizures
how is variance of a variable calculated
square of the correlation coefficient
r^2
what is the airway and spontaneous ventilation like in moderate sedation?
airway - no intervention required
spontaneous ventilation - adequate
what is the airway and spontaneous ventilation like in deep sedation?
airway - intervention may be required
spontaneous ventilation - may be inadequate
how much fibrinogen does a unit of cryoprecipitate contain?
200 mg/unit
inhaled anesthetics in order of decreasing potency (lower MAC)?
isoflurane > sevoflurane > desflurane > nitrous oxide
the Meyer-Overton correlation describes the relationship between lipid solubility and…
anesthetic potency
what is the definition of 1 MAC?
in 50% of subjects, prevents movement in response to an abdominal incision
what is the definition of 0.25 MAC?
in 50% of subjects, renders subjects with amnesia
what is the definition of 0.5 MAC?
in 50% of subjects, renders subjects unconscious
what is the definition of 1.3 MAC?
in 50% of subjects, renders subjects with blunted autonomic responses
alpha-1 receptor second messenger?
increased IP3 and DAG
increased Ca2+ and increased PKC
alpha-2 receptor second messenger?
decreased cAMP
decreased Ca2+
beta-1 receptor second messenger?
increased cAMP
increased Ca2+
beta-2 receptor second messenger?
increased cAMP
decreased Ca2+
effect of perioperative initiation of beta-blockers?
decreases rate of MI, but increases risk of stroke and mortality
the ECF is ____ of the total body water
1/3
the intravascular component is _____ of the ECF
1/4
the intravascular fluid compartment is _____ of the total body water
1/12
onset of action after intubation dose (0.6 mg/kg) of rocuronium?
1-2 min
total body water proportion _____ in obesity
decreases. adipose tissue contains much less water
sensitivity of evoked potentials to depression by volatile anesthetics?
SSEP > MEP > BAEP
what tidal volume is needed to measure PPV?
> 8 mL/kg
which medication decreases gastric fluid volume?
metoclopramide
what happens to lung compliance with increasing age?
increases. elastic recoil of lung parenchyma decreases with age
think saggy balls
what happens to closing capacity with increasing age?
increases
closing capacity is the lung volume at which small airways begin to close during expiration
what does the internal branch of the superior laryngeal nerve innervate?
sensory innervation ABOVE the vocal cords
what does the recurrent laryngeal nerve innervate?
motor - all of the muscles of the larynx with the exception of the cricothryoid muscle
sensation - visceral sensation TO the vocal cords and infraglottic region
how is cisatracurium metabolized?
hofmann elimination
which NMBD is affected most by renal disease?
vecuronium has the most prolonged duration of action in renal failure pts
which NMBD is NOT affected by renal disease?
duration of action of rocuronium is largely unaffected by renal failure
how is mivacurium metabolized?
by BCHE and therefore its effect is prolonged in pts with BCHE deficiency
