inhalation anesthesia Flashcards

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
Q

what is the site of action for amnesia

A

limbic system - hippocampus/amygdala

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26
Q

what is the reliable measure for amnesia?

A

none - but can use BIS or EEG

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27
Q

what is the site of action for analgesia?

A

spirothalmic tract

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28
Q

how is analgesia measured in immobile / unconscious pt

A

cannot be directly measured. HR and BP are suggestive

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29
Q

what is the site of action for unconsciousness

A

cortex/thalamus/brainstem

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30
Q

CNS depression occurs in 2 ways

A

enhancement of inhibitory channels & blocking excitatory channels

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31
Q

as the number of F atoms is increased, metabolism

A

decreases

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32
Q

metabolism of inhalation agents is thru

A

phase 1 oxidation (hepatic)

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33
Q

percentage of halothane metaboized

A

45% (large amt! caused hepatitis)

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34
Q

percentage of sevo metabolized

A

5-8%

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35
Q

percentage of iso metabolized

A

0.2%

36
Q

percentage of des metabolized

A

.02%

37
Q

MAC of nitrous oxide

A

104

38
Q

MAC of sevo

A

2

39
Q

Mac of iso

A

1.4

40
Q

mac of des

A

6

41
Q

oil: gas of nitrous oxide

A

1.4

42
Q

oil: gas of des

A

19

43
Q

oil: gas of sevo

A

51

44
Q

oil: gas of iso

A

98

45
Q

blood:gas of nitrous oxide

A

0.47

46
Q

blood:gas of sevo

A

0.65

47
Q

blood:gas of iso

A

1.4

48
Q

blood: gas of des

A

0.45

49
Q

at equilibrium, partial pressures are equal where

A

alveoli, blood, CNS

50
Q

the more blood soluble the drug,

A

the more drug wants to stay in blood thus slow to move to brain/CNS

51
Q

N20 is low blood:gas soluble so induction will be

A

fast

52
Q

blood solubility is important for ___ and ___

A

induction and emergence

53
Q

the higher the blood solubility, the ____ the uptake

A

slower

54
Q

with a slower uptake, your patient will go to sleep faster or slower

A

slower

55
Q

how does the rate of metabolism and excretion of an inhaled agent compare to the rate of delivery to and removal from the lungs

A

it is minimal - so you can control your agent and have effects in seconds/mins

56
Q

what is involved in enhancement of inhibitory channels

A

hyperpolarization of neuron - Cl- enters thru GABA or glycine, slows down transmission. effux of K+

57
Q

how does blocking excitatory channels work

A

prevents depolarization of neuron, blockage of glutamate and NMDA

58
Q

how many flourines does iso have

A

5

59
Q

how many flourines does des have

A

6

60
Q

how many flourines does sevo have

A

7

61
Q

as temp increases, vapor pressure ____

A

increases

62
Q

at equilibrium, the pressure exerted by molecular collisions of the gas against the container walls is the

A

vapor pressure

63
Q

daltons law

A

sum of partial pressures

64
Q

anesthetic gases equilibrate based on

A

partial pressures

65
Q

solubility is the tendency of a gas to

A

equilibrate with a solution

66
Q

henrys law explains

A

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
Q

solubility coefficient measures

A

v dissolved/v liquid at 37…. balances between gas above and how much is dissolved in liquid below.

68
Q

concentration of each gas in a mixture depends on what two things

A

1) its partial pressure in the gas phase and 2) its solubility within that solution

69
Q

there is no gas phase at what interface

A

blood - target tissue (liquid phase that equilibrates

70
Q

brain: blood of des

A

1.29

71
Q

brain:blood of sevo

A

1.70

72
Q

brain:blood of iso

A

1.57

73
Q

equilibrium happens fastest in which organs

A

vessel rich

74
Q

what happens when an agent builds up in the fat

A

longer emergence. wake up is long with sevo and iso in the obese, shorter with des

75
Q

how do we evaluate our inhaled anesthetics

A

end-tidal concentration

76
Q

end tidal concentration doesnt account for

A

whats hanging around in your brain and fatty tissue

77
Q

which agent is metabolized the least

A

des

78
Q

the speed of an inhaled anesthetic is determined by its solubility and expressed as

A

blood: gas solubility coefficient

79
Q

what are the two most soluble volatile anesthetics

A

iso , halo

80
Q

oil:gas coefficient is related to an agent’s

A

potency

81
Q

the slowest induction is possible with

A

halo, increased cardiac output state

82
Q

calculate the partial pressure of 6% des at sea level

A

.06 x 760= 45.6

83
Q

why measure alveolar concentration?

A

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
Q

the vessel rich group accounts for only __ % of body weight, yet it receives ___% of the cardiac output

A

10, 75 (apex)

85
Q

whats the primary mechanism by which inhalation anesthetic is removed from the body

A

exhalation thru the lungs. hepatic is a secondary mechanism. (apex)