Volatile Anesthetics - Quiz 1 Flashcards

1
Q

Who administered the first ether anesthetic and in what year?

A

Crawford Long

1842

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2
Q

Who administered NO for a tooth extraction and what year?

A

Horace Wells

1845

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3
Q

Who administered chloroform and when?

A

James Simpson

1847

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4
Q

When were modern gases introduced

A

Halothan 1956

Sevo/Des 1960

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5
Q

All inhalation agents share a common characteristic that promotes their clinical use today, what is it?

A

a low blood:gas solubility coefficient, which creates a favorable pharmacokinetic profile.

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6
Q

How are the carbon atoms bound?

A

by covalent bonds

the more sharing = stonger they are

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7
Q

c-c

A

alkane

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8
Q

c=c

A

alkene

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9
Q

c≡c

A

alkyne

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10
Q

c-o-c

A

Ethers

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11
Q

CH3

A

Methyl

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12
Q

CH2, CH3

A

Ethyl

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13
Q

All commonly used inhalation agents are ethers or aliphatic hydrocarbons with no more than ____ carbon atoms.

A

4

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14
Q

What is an aliphatic compound?

A

a hydrocarbon compound containing carbon and hydrogen joined together in straight chains, branched trains or non-aromatic rings.

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15
Q

If the chemical structure becomes longer than 4-5 carbons, what happens?

A

looses effect

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16
Q

Modern anesthetic agents are ______, but what is the exception

A

halogenated

nitrous oxide

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17
Q

What does the addition of fluorine [F], chlorine [Cl], bromine [Br], or iodine [I] do to the anesthetics characteristics?

A

Potency (lipid solubility)
Arrhythmogenic properties
Flammability
Chemical stability

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18
Q

When does potency increase?

A

increases when a halogen with a lower atomic mass unit (amu) is replaced by a heavier halogen

(bromine 80 amu substituted for fluorine at 19 amu)

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19
Q

What makes volatile anesthetics favor the occurance of arrhythmias?

A

increasing the number of halogen atoms within a volatile agent

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20
Q

What do anesthetics interact with that may facilitate arrhythmias?

A

K+, Ca+, and Na+ channels

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21
Q

What does substituting hydrogen atoms with halogens in regards to flammability?

A

flammability is reduced and chemical stability is enhanced.

if only hydrogen = very flammable

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22
Q

What is the best example of chemical stability?

A

desflurane – a compound that contains fluorine as its only halogen and thus strongly resists biodegradation

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23
Q

What are the 5 halogen elements?

A

fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At)

(group 17)

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24
Q

The group of halogens is the only periodic table group that contains elements in all three familiar states of matter at standard

A

temperature and pressure

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25
Q

All of the halogens form _____ when bonded to hydrogen.

A

acids

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26
Q

The halogens are ALL

A

toxic

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27
Q

The chemical structure of each agent determines the extent to which it is metabolized. Typically , increasing the number of fluorine atoms on an anesthetic molecule

A

slows biodegradation

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28
Q

Biodegradation of all currently used inhalation agents is predominantly accomplished by way of

A

hepatic metabolism through oxidation (phase I)

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29
Q

Halothane is 45% metabolized, what did it use to cause?

A

halothane hepatitis

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30
Q

What is the % metabolized in
Iso
Des
Sevo

A

Iso 0.2
Des 0.02
Sevo 4-5%

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31
Q

Absorption phase =

A

uptake

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32
Q

Metabolic phase =

A

biotransformation

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33
Q

Excretion phase =

A

elimination

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34
Q

_______ anesthetics are among the most rapidly acting drugs in existence

A

Inhaled

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35
Q

Of the inhaled anesthetics, only 2 are “true gases” the other potent agents are vapors of volatile liquids. Which 2 are they?

A

NO2 and O2

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36
Q

All gases are _________ and have a _____ molecular weight

A

non-ionized

low

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37
Q

What is the goal of anesthetics?

A

to create a concentration and get it to the CNS. Happens by creating partial pressures.

This is accomplished by creating a MAC - Minimum alveolar concentration to get it up to CNS

38
Q

What 4 things does general anesthesia produce?

A

unconsciousness
Amnesia
analgesia
Immobility

39
Q

What are the secondary effects of general anesthesia?

A

Reduces stress response to surgical stimuli
(if I was to take a knife and cut you – increased HR, BP, RR) - stops that

Cause arrhythmias

40
Q

What is the Meyer-Overton rule?

A

Lipid solubility is directly proportional to potency.

41
Q

Reversal of anesthetic can be achieved with the application of

A

pressure

42
Q

A reduction in body temperature does what to the anesthetic requirement?

A

lowers anesthetic requirement

43
Q

What is unitary hypothesis?

A

The theory proposed that all inhalation agents work via a similar mechanism of action but not necessarily at the same site of action.

44
Q

What is the current theory of how anesthetics work?

A

is interactions with multiple and diverse ion channels in the brain. Anesthetic sites of action include supraspinal and spinal anatomic structures - and on the molecular level, multiple protein structures (receptors, channels)

45
Q

What does the spinal cord mediate?

A

immobility to painful stimulus

weak inward-rectifying K+ Channels, and inhibiting glycine and GABA receptors

46
Q

What does supra spinal mediate?

A

amnesia and immobility via glycine, sodium and NMDA receptors.

47
Q

Amnesia requires the lowest followed by hat 3 (in order!!)

A

sedation, unconsciousness, and immobility

If I want someone to not remember, I don’t have to give as much of the drug, I have to give way more if I want immobility

48
Q
What is the MAC % of
Nitrous Oxide
Des
Iso
Sevo
A

Nitrous Oxide 104% (can’t get to this)
Des 6
Iso 1.4
Sevo 2

49
Q

The potency of an anesthetic increases as the lipid solubility

A

increases

50
Q
What is the oil:gas lipid solubility of 
Nitrous Oxide
Des
Sevo
Iso
A

Nitrous Oxide 1.4
Des 19
Sevo 51
Iso 98

51
Q

Why do agents of high solubility want to go to the brain?

A

the brain is made of fat

52
Q

How do anesthetics probably work?

A

anesthesia by enhancing the function of inhibitory ion channels and by blocking the function of excitatory ion channels

53
Q

Enhancing the function of inhibitory ion channels leads to hyperpolarization of the neuron. What does hyperpolarization mean?

A

slows everything down

54
Q

What are the 2 inhibitory ion channels

A

glycerine and GABA

55
Q

Where does glycerine work and what does it do?

A

Major inhibitory mediators in spinal cord

Mediate part of immobility

56
Q

What does GABA control?

A

Hypnosis

57
Q

hyperpolarization happens when ______ enters the receptors or when there is an efflux of ______

A

Cl

K

58
Q

What is the excitotory channel?

A

Glutamate

59
Q

Explain glutamate receptors

A
Principle excitatory neurotransmitter
G protein-coupled receptors
Ligand-gated receptors
       NMDA *** (most familiar with)
       AMPA
       Kainate
60
Q

What are the 2 pore potassium channels

A

Trek and Task

Role and GA and deep sleep

61
Q

What does the Voltage-gated sodium channels release?

A

neurotransmitter release

62
Q

Immobility is mediated by the

A

spinal cord

63
Q

Immobility IS measurable, what is this?

A

MAC (minimum alveolar concentration)

64
Q

Immobility occurs via activation of the ________ ________ _________ which originate in periaqueductal gray matter of the brainstem. Activation of these pathways inhibit nociceptive input in the dorsal horn of the spinal cord.

A

descending noradrenergic pathways

65
Q

The length of the anesthetic molecule is significant in that “immobility” is lost if _______ atom chain length exceeds a distance of ______ carbon atoms(5 angstroms)

A

Carbon

4-5

66
Q

What is the a fundamental component of general anesthesia.

A

amnesia

67
Q

What supra spinal structures are considered highly probable targets for the effects of anesthetics.

A

amygdala, hippocampus, and cortex

68
Q

Does amnesia have a reliable measure?

A

NO

69
Q

The limbic system of the brain is the primary part of the brain that regulates _______. The limbic system contains the amygdala complex the hippocampus the thalamus and the hypothalamus.

A

emotion

70
Q

The amygdala complex is one of the main areas to process emotional content of ________ and ________.

A

Behavior and memory

71
Q

What is the main purpose of the amygdala?

A

filter the important sensory information from the unimportant.

72
Q

What does the hippocampus do?

A

converts objective versions of events from short term to long term memory.

73
Q

Can analgesia be measured?

A

No

Intraoperative measures of pain suggest that inhaled anesthetics do not suppress the perception of painful stimuli. (increased HR and BP)

74
Q

At equilibrium, ______ partial pressure will equal ______ partial pressure, which in turn will equal _______ partial pressure.

A

CNS
Blood
Alveolar

75
Q

Does metabolism, excretion and redistribution happen a lot with inhaled anesthetics?

A

No minimal

76
Q

What is Vapor pressure

A

the pressure exerted by molecular collisions of the gas against the container walls

77
Q

What happens to volatile anesthetics in a closed container?

A

molecules of the substance will equilibrate between the liquid and gas phases.

78
Q

What is Daltons Law?

A

the sum of the partial pressures of each gas in a mixture of gases equals the total pressure of the entire mixture.

Ptotal = Pgas1+Pgas2+…

79
Q

What is the PP of Oxygen at sea level?

A

760 X .21 = 159.6

80
Q

“partial pressure” is determined from the portion of volatile agent in the

A

gas phase

81
Q

Gas equilibration is base on ________ not _________

A

partial pressures

not gas concentration

82
Q

Explain solubility

A

term used to describe the tendency of a gas to equilibrate with a solution

83
Q

Which law describes the relationship of concentration of a gas in solution to the partial pressure of the gas with which the solution is in equilibrium

A

Henreys Law

84
Q

What is solubility coefficient?

A

a certain volume of gas the is dissolved in a certain volume of liquid

85
Q

The concentration of anesthetic in target tissue (brain) depends on the partial pressure at _______ and the _____ ______ ______

A

Equilibrium

Target tissue solubility

86
Q

Because inhaled anesthetics are gases, and partial pressures equilibrate throughout a system, monitoring the ______ _______ of inhaled anesthetics provides an index of their effects in the brain.

A

Alveolar concentration

87
Q

What happens to gas in the brain when the agent is turned off

A

Turning the gas off creates a negative pull until equilibration

88
Q

Which agent should we use on obese patients and why?

A

Des blood:gas coefficient is 0.42. (the amount of anesthetic bound to the blood and not readily released to tissues) this # is low. Therefore, does not readily go into the fat. (adipose tissue creates a reservoir for the gas)

89
Q

Which inhaled anesthetic goes into the adipose tissue the most?

A

Sevo

90
Q

What percent of CO goes to the fat, and what does this lead to?

A

6% goes to fat - explains another reason anesthetics stay in adipose tissue for long time

91
Q

Where is the majority of the cardiac output going?

A

75% going to vessel rich group

92
Q

Which inhaled anesthetic does not like to come out of muscle?

A

Sevo