inhalation anesthesia Flashcards

(85 cards)

1
Q

covalent bonds involves

A

sharing of electron pairs

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2
Q

all commonly used inhalation agents are ___ or _____

A

ethers or aliphatic hydrocarbons

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3
Q

anesthesia affect is lost if the chain exceeds

A

4 carbon atoms

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4
Q

modern inhaled agents are ____ hydrocarbons with exception to ___

A

halogenated, N20

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5
Q

heavier halogenated agent ___ potency

A

increases

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6
Q

ceiling effect of affection of F to ether

A

becomes more potent, then its as a strong convulsant, finally changes to inert compound with full fluorination

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7
Q

lipid solubility is ___ proportional to potency

A

directly

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8
Q

increase potency, ___ MAC

A

decrease

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9
Q

increase lipid solubility, ___ potency

A

increase

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10
Q

increasing # of halogenated agents, ___ arrhythmias

A

increase

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11
Q

MAC is ___ proportional to potency

A

indirectly

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12
Q

more hydrogens, ____ flammable

A

more

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13
Q

more halogens, ____ flammable

A

less

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14
Q

more halogens, ____ stable

A

more

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15
Q

one with all the same __ is ___ stable than one with different ___

A

halogens, more, halogens

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16
Q

why is des metabolized a 1/10th that of iso

A

because it contains F as its only halogen and thus strongly tests biodegradation

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17
Q

flammability is ___ and chemical stability ____ by substitution hydrogen atoms with halogens

A

reduced, enhanced

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18
Q

are inhaled anesthetics ionized or non-ionized?

A

non-ionized

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19
Q

4 elements of general anesthesia

A

unconsciousness, amnesia, analgesia, immobility

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20
Q

increase lipid solubility, ___ MAC

A

decrease

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21
Q

decrease temp, ____ anesthetic requirement

A

decrease (think slowed metabolism)

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22
Q

how is immobility measured?

A

MAC

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23
Q

what is the site of action for immobility?

A

dorsal horn of spinal cord - activate descending noradrenergic pathways

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24
Q

immobility is lost if length exceeds ____ carbon atoms

A

4-5

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25
what is the site of action for amnesia
limbic system - hippocampus/amygdala
26
what is the reliable measure for amnesia?
none - but can use BIS or EEG
27
what is the site of action for analgesia?
spirothalmic tract
28
how is analgesia measured in immobile / unconscious pt
cannot be directly measured. HR and BP are suggestive
29
what is the site of action for unconsciousness
cortex/thalamus/brainstem
30
CNS depression occurs in 2 ways
enhancement of inhibitory channels & blocking excitatory channels
31
as the number of F atoms is increased, metabolism
decreases
32
metabolism of inhalation agents is thru
phase 1 oxidation (hepatic)
33
percentage of halothane metaboized
45% (large amt! caused hepatitis)
34
percentage of sevo metabolized
5-8%
35
percentage of iso metabolized
0.2%
36
percentage of des metabolized
.02%
37
MAC of nitrous oxide
104
38
MAC of sevo
2
39
Mac of iso
1.4
40
mac of des
6
41
oil: gas of nitrous oxide
1.4
42
oil: gas of des
19
43
oil: gas of sevo
51
44
oil: gas of iso
98
45
blood:gas of nitrous oxide
0.47
46
blood:gas of sevo
0.65
47
blood:gas of iso
1.4
48
blood: gas of des
0.45
49
at equilibrium, partial pressures are equal where
alveoli, blood, CNS
50
the more blood soluble the drug,
the more drug wants to stay in blood thus slow to move to brain/CNS
51
N20 is low blood:gas soluble so induction will be
fast
52
blood solubility is important for ___ and ___
induction and emergence
53
the higher the blood solubility, the ____ the uptake
slower
54
with a slower uptake, your patient will go to sleep faster or slower
slower
55
how does the rate of metabolism and excretion of an inhaled agent compare to the rate of delivery to and removal from the lungs
it is minimal - so you can control your agent and have effects in seconds/mins
56
what is involved in enhancement of inhibitory channels
hyperpolarization of neuron - Cl- enters thru GABA or glycine, slows down transmission. effux of K+
57
how does blocking excitatory channels work
prevents depolarization of neuron, blockage of glutamate and NMDA
58
how many flourines does iso have
5
59
how many flourines does des have
6
60
how many flourines does sevo have
7
61
as temp increases, vapor pressure ____
increases
62
at equilibrium, the pressure exerted by molecular collisions of the gas against the container walls is the
vapor pressure
63
daltons law
sum of partial pressures
64
anesthetic gases equilibrate based on
partial pressures
65
solubility is the tendency of a gas to
equilibrate with a solution
66
henrys law explains
why anesthetic gas wants to equilibrate with alveoli, blood, CNS. "At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid"
67
solubility coefficient measures
v dissolved/v liquid at 37.... balances between gas above and how much is dissolved in liquid below.
68
concentration of each gas in a mixture depends on what two things
1) its partial pressure in the gas phase and 2) its solubility within that solution
69
there is no gas phase at what interface
blood - target tissue (liquid phase that equilibrates
70
brain: blood of des
1.29
71
brain:blood of sevo
1.70
72
brain:blood of iso
1.57
73
equilibrium happens fastest in which organs
vessel rich
74
what happens when an agent builds up in the fat
longer emergence. wake up is long with sevo and iso in the obese, shorter with des
75
how do we evaluate our inhaled anesthetics
end-tidal concentration
76
end tidal concentration doesnt account for
whats hanging around in your brain and fatty tissue
77
which agent is metabolized the least
des
78
the speed of an inhaled anesthetic is determined by its solubility and expressed as
blood: gas solubility coefficient
79
what are the two most soluble volatile anesthetics
iso , halo
80
oil:gas coefficient is related to an agent's
potency
81
the slowest induction is possible with
halo, increased cardiac output state
82
calculate the partial pressure of 6% des at sea level
.06 x 760= 45.6
83
why measure alveolar concentration?
the concentration of an agent inside the alveoli is proportional to its concentration inside the blood and this is proportional to the anesthetic inside the brain. while we cannot directly measure the anesthetic in the brain, we use alveolar concentration as a surrogate. (APEX)
84
the vessel rich group accounts for only __ % of body weight, yet it receives ___% of the cardiac output
10, 75 (apex)
85
whats the primary mechanism by which inhalation anesthetic is removed from the body
exhalation thru the lungs. hepatic is a secondary mechanism. (apex)