general Flashcards
(119 cards)
1
Q
MOA of succinylcholine
A
binds post synaptic Nicotinic Ach receptors @ neuromuscular endplate –> opening Na+ channels –> Ca+2 release from SR –> muscle contractions and fasciculations
2
Q
five main nerves that innervate the foot and their coverage
A
posterior tibial (from tibial nerve) - heel/sole and most ligaments/muscles/bones, runs with posterior tibial artery
saphenous nerve (from femoral nerve) - medial aspect of foot including medial malleolus, near great saph vein
superficial personal (from common peroneal) - dorsum of foot
deep peroneal (from common peroneal) - webspace of first and second toes, runs with dorsalis pedis artery
sural nerve (from tibial and peroneal branches) - lateral aspect of foot
3
Q
the only spine level that is motor only
A
C1
4
Q
epidural hematoma shape and common culprit artery
A
convex (bulging in, not a moon) - middle meningeal artery
5
Q
three factors affecting inhalational uptake
A
solubility of agent, pts cardiac output, partial pressure difference of gas btw alveoli and pulmonary vein
6
Q
blood gas partition coefficient desflurane
A
0.45
7
Q
blood gas partition coefficient nitrous oxide
A
0.47
8
Q
blood gas partition coefficient sevoflurane
A
0.65
9
Q
blood gas partition coefficient isoflurane
A
1.4
10
Q
blood gas partition coefficient halothane
A
2.5
11
Q
blood gas partition coefficient methyoxyflurane
A
15
12
Q
changes in cardiac output affect soluble/insoluble agents more
A
soluble (increase CO decrease Fa/Fi of soluble)
13
Q
vessel rich organs
A
brain, spinal cord, heart, liver, kidneys
14
Q
increased FRC increases/decreases uptake of inhalation agent
A
decreases
15
Q
soluble/insoluble agents are more affected by VQ mismatch
A
insoluble
16
Q
left to right cardiac shunt affects insoluble/soluble agents more
A
neither - does not affect
17
Q
right to left cardiac shunt affects insoluble/soluble agents more
A
insoluble
18
Q
two factors that affect influence rate of alveolar agent concentration increases
A
Fi (inspired concentration) + alveolar ventilation (min ventilation)
19
Q
while hyperventilation increases the rate of Fa/Fi, the change is more pronounced in soluble/insoluble agents
A
soluble
20
Q
MAC is analogous to which pharm concept
A
ED 50
21
Q
in descending order, MAC needed to block a response (ie laryngoscopy, intubation, incision, trap squeeze, voice command, tetanic stimulation)
A
intubation, skin incision, tetanic stimulation, laryngoscopy, trap squeeze, voice command
22
Q
how much MAC to prevent 99% movement on skin incision
A
1.3 MAC
23
Q
factors that decrease ____ tend to decrease MAC (hypoxia, hypotension, temperature, age, drugs)
A
cerebral metabolic rate
24
Q
for patients older than a year, MAC decreases approximately ___% per decade of life
A
6-7%
25
MAC decreases linearly with temperature where 1 degree C decrease results in ___% decrease in in MAC
4-5%
26
drugs that increase MAC
inhibition of catecholamine reuptake (amphetamines, ephedrine, chronic alcohol use)
27
drugs that decrease MAC
opiods, benzos, barbiturates, propofol, ketamine, alpha agonists, IV administered local anesthetics, acute alcohol ingestion
28
standard deviation of MAC
10%
29
how do people on nitrous oxide breathe
shallow and fast, reduced response to CO2 and hypoxia
30
maximum analgesic effect of nitrous at this percent
35%
31
concentrations of nitrous oxide greater than __% increase cerebral blood flow and potentially increase ICP
60%
32
why most CV anesthesiologists avoid nitrous in pulmonary HTN
concern about sympathetic stimulation that could increase PVR
33
enzyme inactivated by nitrous by oxidizing cobalt in B12 leading to genetic and protein aberrations
methionine synthase
34
agent that causes megaloblastic anemia, esp in the elderly
nitrous oxide
35
the primary mechanism that inhlational agents (iso, des, sevo) cause decrease in BP
SVR decrease
36
change in HR caused by iso/des/sevo
increased (preserves CO in the face of decreased SVR)
37
how halothane directly depresses myocardial contractility and SV
altering concentrations of intracellular calcium at several subcellular targets
38
inhalational agents sensitize the myocardium to ___
epinephrine
39
one half the dose of epi required to produce 3+ PVCs is considered safe, which is ___ ug/kg during iso anesthesia
3 ug/kg epi during isoflurane anesthesia
40
Plasma local anesthetic concentrations following regional techniques, from highest to lowest, are Mnemonic - IICEBALLS:
intravenous > intercostal > caudal > epidural > brachial plexus > axillary > lower limb > subcutaneous
41
fast conducting nociceptive fibers
A delta
42
Type A/B/fibers myelination
heavy, light, none
43
motor myelinated fast fibers
A alpha
44
Revised Cardiac Risk Index Variables:
1) History of ischemic heart disease
2) History of congestive heart failure
3) History of cerebrovascular disease
4) Insulin therapy for diabetes
5) Preoperative serum creatinine > 2.0 mg/dL
6) High-risk type of surgery
45
The Alveolar Gas Equation:
PAO2 = FiO2 * (Pb - PH2O) - PaCO2 / R
Where Pb is the barometric pressure, PH2O is the vapor pressure of water, PaCO2 is the arterial CO2 partial pressure, and R is the respiratory quotient.
46
Clark, Galvanic and paramagnetic measure this
oxygen
47
Severinghaus electrode measures this
CO2
48
Sanz electrode measures this
pH
49
in an ABG, the ___ is calculated
bicarb HCo3
50
Aldrete components
Activity (move 4 ext on command), Breathing (no dyspnea or apnea), Circulation (SBP within 20%), Consciousness (fully awake), Oxygen sat (>92% RA)
51
MELD: "I Crush Several Beers Daily"
INR, creatinine, sodium, bilirubin, dialysis
52
Childs-Pugh: "Pour Another Beer At Eleven"
PT, Ascites, Bilirubin, Albumin, Encephalopathy
53
for every 10 mmHg change in PaCO2, pH goes ___ in the opposite direction
0.08 units
54
where does 90-95% of CO2 in blood go to be transported
RBCs
5-10% dissolves
small amount reacts with H20 to form carbonic acid
55
99% of CO2 in RBCs is hydrated by ___ to form carbonic acid, which dissociates to bicarb and H+. Bicarb then diffuses out, and to replace the negatives in RBC, ___ shifts in, also known as __ phenomenon.
carbonic anhydrase, chloride, Hamburger
56
Presence of CO2 results in release of H+ and a more acidic environment that shifts O2 dissociation curve __, where O2 is less attractive and Hg has greater ability to make carbaminohemoglobin, also know as __ effect.
right, Haldane
57
compliance is dependent on lung ____
volume
58
Ohms law
pressure = resistance * flow
59
compliance equation for respiratory system
1/CRS = 1/C of Lungs + 1/C of CW
60
driving pressures into the lungs =
atm pressure - alveolar pressure
61
3 major ways to decrease lung compliance
change the lung intrinsic function, decrease FRC, decrease surfactant
intrinsic lung: pleural/interstitial/alveolar fibrosis, emphysema,
decrease FRC: ascites, pleural effusion, pericardial effusion, cardiomegaly, PNA, atelectasis, poliomyelitis, kyphoscoliosis, pulm artery obstruction, GA
decrease surfactant: pulmonary edema (+ shape change),
62
change in CMR o2 relative to decrease in temperature
decrease 7% per decrease 1 degree C
63
CPP =
MAP - (ICP or CVP, whichever higher)
64
changes physiologically when pt hypercarbic (respiratory acidosis)
neuro = increase CBF /CBV
resp = increase MV until CO2 100 (then stops), increase PVR, increase hypoxic pulm vasoconstriction
CV = increase BP/HR until CO2 ~90, arrthymias
GI = increase hepatic/portal blood flow when awake (depending on light or deep GA changes things)
renal = compensatory metabolic alkalosis by holding onto bicarb
metabolic = epi/NE increased release, K+ released extracellularly and hard to get it back into cells, decreased pH makes LA less effective
heme = Hgb dissociation curve shifts R
65
arterial O2 content equation CaO2
| basically same venous O2 content equation CvO2
CaO2 = (Hb x 1.39 x SaO2/100) + (PaO2 x 0.003)
| ml / dl or multiply by 10 to get ml /L
66
main law governing how surfactant keeps small bubbles open when the wall tension is high
```
Laplace
P ~ 2T/r for a sphere
P is net pressure on sphere
T is surface tension
r is radius of sphere
```
as long as surface tension decreases more than radius, the pressure will decrease and the surrounding airway and alveolar fluids will not be sucked
67
lamellar bodies in type II pneumocytes contain these three main components of surfactant
phospholipids, special surfactant proteins (A-D), and calcium as a cofactor
68
normal adult airway resistance
0.5 to 1.5 cm H20/L/sec
69
causes of increased airway resistance
broncospasm, airway secretions, turbulent flow, emphysema, mucosal congestions, edema, inflammation, pneumothorax, long narrow tracheal tubes
70
two determinants of pulmonary blood flow
gravity & hypoxic pulmonary vasoconstriction
71
four zones of lungs
collapse (dead space, no blood flow b/c blood cant overcome alveolar pressure)
waterfall (flow dependent on arterial pressure - alveolar pressure)
distention (flow dependent on arterial pressure - venous pressure)
interstitial pressure (flow determined by different in PPA and PISF)
72
HPV is a local response of __ __ __ __ to a decreased regional alveolar __
pulmonary arterial smooth muscle
| Po2
73
effect of IV and inhalational anesthetics on HPV
IV anesthetics do not inhibit HPV
inhaled agents and potent vasodilators inhibit HPV
inhaled NO pulm specific dilator that helps dilate and bring blood flow only to ventilated alveoli
74
rib number where V/Q = 1
rib 3
75
formula for anatomic dead space
0.5 ml / kg
76
reflex that constricts airways to alveoli that are unperfused
bronchiolar constrictive relfex
77
normally physiologic dead space (anatomic dead space+ alveolar dead space) is ___ of tidal volume
1/3
78
how does age affect closing volume and closing capacity
both increase with age
79
extending the neck and protruding the jaw can _x increase dead speace
2x
| double
80
total shunt % Qs/QT of CO in normal person
6-10% of total CO
81
how opioids cause nausea and vomiting
activating area postrema of brain stem
82
how opiods cause miosis
activating Edinger-Westphal nucleus of oculomotor nerve
83
opioids that can cause histamine induced bronchospasm (and histamine release in general)
morphine, meperidine
84
opioid best for shivering through __ receptor action, and dose
meperidine, 12-25mg as slow IV push
| kappa receptor
85
renal effects of inhaled agents
not much - autoregulation preserved, some toxic metabolic products that are more common with enflurane/methoxyflurane and no longer availabl
otherwise the kidney does not like intravascular volume depletion, anemia, catecholamine stimulation leading to unopposed vasoconstriction, PPV, and laparoscopy
86
percent of CO that the liver gets
25%
1 ml / min / g of liver tissue
liver = 1200-1500 g
87
how does the liver get blood supply
1/3 hepatic artery and branches
2/3 portal vein and its branches
each contributes 50% of its oxygen consumption
88
mechanism of halothane hepatitis
allergic response to oxidative (trifluoroacetic acid) metabolites
89
inhalational agent most metabolized by liver (that we use)
sevo, 3-5%
90
CYP enzyme that does oxidative metabolism to the inhalation agents, causing release of F- ions
CYP2E1
91
least potent cerebral vasodilator of the used inhalational agents
isoflurane
92
order of blocked signals with LA
temp, proprioception, motor, sharp pain, light touch
93
ester LA make a ___ metabolite that gives some people insensitivity (not a true allergy)
PABA
94
amides LA are metabolized by __ system in ___
P450, liver
95
what opioid property correlates with duration of action
lipid solubility (low solubility = long duration)
96
what two opioid properties affect onset of action
% unionized and lipid solubility (to go fast want higher % unionized and high solubility)
97
protein binding is by __ for acidic drugs and __ for basic drugs
albumin
| alpha-1 acid glycoprotein (AAG)
98
3 drugs that do NOT undergo lung metabolism
epinephrine, isoproterenol, dopamine
99
opioid with one of the lowest pKa
alfentanil
100
opioid with lowest Volume of distribution
alfentanil
101
opioid with highest unionized %
alfentanil
102
opioid with highest lipid solubility
sufentanil
103
potency of LA is determined by this property
lipid solubility
104
duration of action of LA is determined by these two properties
vasoconstrictors and protein binding
105
onset of LA blockade is primarily determined by this property of LA
pKa and surrounding pH
| but also molecule size and concentration
106
7 factors that decrease acetylcholine release
1) Antibiotics (clindamycin, polymyxin)
2) Magnesium: antagonizes calcium
3) Hypocalcemia
4) Anticonvulsants
5) Diuretics (furosemide)
6) Eaton-Lambert syndrome: inhibits P-type calcium channels
7) Botulinum toxin: inhibits SNARE proteins
107
how propofol affects cerebral blood flow, metabolic rate and ICP
decreased cerebral metabolism and blood flow and ICP
108
who propofol affects BP
decrease SVR first and then depresses myocardial contractility
109
propofol binds all 5 GABA-A subunits, but etomindate only binds __ and __
Beta 2 and beta 3
110
enzyme inhibited by etomidate causing corticoadrenal suppression
11-beta-hydroxylase
111
induction agent that can cause myclonus in 30-60% of patients (when opioids and midaz not given)
etomidate
112
how often and when thrombophebitis appears after etomidate administration
25% of time, up to 24 hours after
113
induction agents that can precipitate porphyria attack
etomidate, thiopental
114
SE (10) of etomidate as induction agent
```
adrenocortical suppression
seizures
myoclonus
porphyria attack
pain on injection
thrombophelbitis
PONV
anaphylactoid reactions
postop hiccups
postop sense of restlessness
```
115
MOA of ketamine
noncompetitive antagonism of NMDA receptors
| plus so much more
116
opioids enhance parasympathetic tone by __
direct stimulation of vagal nucei
117
3 drugs to treat opioid induced muscle rigidity
nondepolarizing blocking agents, induction agents (prop), benzos
118
factors that cause contraction of sphincter of Oddi
cholecystokinin (CCK), opioids, vagus nerve transmission, following a meal
119
treatments (6) for opioid induced biliary spasm
```
(naloxone)
anticholinergics
calcium channel blockers
nitroglycerin
isosorbide
glucagon
```
