Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

*Pharmacology > Apex- Volatile Anesthetics-pharmacokinetics > Flashcards

Apex- Volatile Anesthetics-pharmacokinetics Flashcards

1
Q

Which Anesthetic is shown?

A

Sevo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Inhaled anesthetic are categorized into what 3 groups?

A

Ethers (R-O-R) —> iso, sevo, des,
Alkanes (R-H) —> H for halothane, cHloroform
Gases —> Nitrous oxide, cyclopropane, xenon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which gases have chiral carbons and which do not?

A

Chiral carbons : Des & ISO

No: Sevo

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

At ATM pressure and room temp, which type of inhaled anesthetic will exist as liquids? (Ethers, alkanes, gases)

A

Ethers and Alkanes (Gases exist in gaseous form)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Out of Ethers, alkanes, and gases, which have a characteristic “C-O-C”

A

Ethers

“Ether Bridge” = “C-O-C”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the addition of a heavier chlorine atom do? Which gas has this?

A

ISO - increases POTENCY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If full fluorination decreases potency, why is sevo 3x more potent than DES?

A

Likely due to the propyl side chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 2 classes of ethers? Examples?

A

Methyl-isopropyl-ether (Sevo)

Methyl-ethyl-ether (ISO & Des)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Does halogen have an ether bond?

A

No, It’s a halogenated hydrocarbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What has a bromine atom?

A

Halogenated agents (Halothane, chloroform)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How many fluorines does ISO have? What else is characteristic to ISO?

A

5 flurines & 1 chlorine “Cl” atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many flurines does Sevo have?

A

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many flurines does Des have?

A

6 “Fully flurinated”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

1-Chloror, 2, 2, 2 - Trifluroethyl difluromethyl ether

A

Isoflurane

Trifluro = 3
+ difluro = 2
5 flurines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Fluromethyl, 2, 2, 2 - Trifluro-1- (Trifluromethyl) ethyl ether

A

Sevo

Flur = 1
+ trifluro = 3
+ trifluro = 3
= 7 flurines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How much more potent is ISO than sevo and Des

A

X2 more than sevo

5x more than Des

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Difluromethyl 1, 2, 2, 2 Tetrafluroethyl ether

A

Des

Difluro = 2
+Tetrafluro =4
=6 flurines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What chemical structure?

A

Des

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

2-Bromo-2-Chloro-1,1,1, Trifluroethane

A

Halothane
1. bc of Bromo
& 2 - Trifluro-> has 3 flurines
& lacks an ether bridge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What 2 things are capable of transforming volatile anesthetic into toxic compounds?

A

CO2 absorbent and the liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which agent is unstable, even in the presence of hydrated soda lime?

A

Sevo (Compound A; minimal FGF requirements)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What agent(s) can become unstable in desiccated soda lime and produce carbon monoxide?

A

ISO and Des (Des>ISO bc DES is the devil)

Sevo is unstable in hydrated soda lime

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Vapor pressure of Sevo

A

157

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Vapor pressure of Des

A

666

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Vapor pressure of ISO

A

238 (240)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Vapor pressure of N20

A

38,770

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Boiling point of Sevo

A

59 C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Boiling point of Des

A

23 C(25)

2*3 =6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Boiling point of ISO

A

49 C(50)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Boiling point of N20

A

-88 C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Molecular weight of Sevo

A

200g/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Molecular weight of Des

A

168g/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Molecular weight of ISO

A

184g/mol(186- flip 168 for des to 186 for iso)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Molecular weight of N20

A

44g/mol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Which inhalational agent has preservatives

A

None

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Which inhalational agent is stable in dehydrated CO2 absorbent?

A

N20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Toxic byproduct of each inhalational agent

A

Sevo. Compound A
ISO & Des - carbon monoxide (Des>ISO) (in desiccated soda lime)
N20 - none

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Vapor pressure is (directly/inversely) proportional to temperature

A

Directly

Increased Temp = increased VP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

At high altitude, a liquid will boil ad higher or lower temperatures?

A

Lower due to lower atmospheric pressures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

The pressure exerted by a vapor in equilibrium with its liquid or solid phase inside a closed container

A

Vapor pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

The fractional amount of pressure that a single gas exerts within a gas mixture

What law?

A

Partial pressure

-Dalton’s law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Total gas pressure in a container = the sum of all the partial pressures exerted by each gas (What law)

A

Dalton’s

P1 + P2 + P3 = Total P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is volume% ?

A

What you set your dial to

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the depth of anesthesia determined by?

A

The PARTIAL PRESSURE of an anesthetic agent in the brain (NOT volume%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

High altitude may lead to underdosing of which agent and why?

A

Desflurane - bc the conventional variable bypass vaporizer automatically compensates for elevation but the Tec6 does not

46
Q

6% of Desflurane at sea level results in a partial pressure of what?

A
  1. 6

0. 06 x 760

47
Q

6% of Des in Denver (1 mile above sea level) results in a delivered partial pressure of what?

A
  1. 2

0. 06 x 620mmHg

48
Q

How does full fluorination affect Des’s PK/PD profile? (3)

A

Decreased potency
Increased vapor pressure
Increased resistance to biotransformation

49
Q

P total = P1 + P2 + P3

A

Dalton’s Law

50
Q

Blood: Gas partition coefficient of Sevo, ISO, Des, N20

A

ISO- 1.43 (I love you, I love ISO - most potent love)
Sevo- 0.69 (next comes the middle man with 69)
N20 - 0.47
Des - 0.42 (4+2 = 6 = des the devil who lives in hell so he’s at the bottom)

51
Q

What describes the ability of an anesthetic agent to dissolve into the blood and tissues?

A

Solubility (B:G coefficient)

52
Q

Anesthetic dissolved in blood/Anesthetic inside alveolus =

A

Blood:Gas partition coefficient

53
Q

Who’s law describes the solubility of gases in a solution?

A

Henrys

54
Q

The speed of induction is a function of what property of the agent?

A

Solubility

  • low solubility = less uptake into the blood = faster rate of rise (of pressure in the alveoli/brain) - faster onset
  • high solubility = more uptake into the blood = slower rate of rise (less pressure able to build in the alveoli/brain) - slower onset
55
Q

The main objective when administering volatile anesthetic is to produce a state of anesthesia by building up a partial pressure of the agent where?

A

Inside the patient’s brain and spinal cord

56
Q

What is FA/FI

A 
FA = the partial pressure of anesthetic in the Alveoli
FI = the concentration leaving the vaporizer
57
Q

Which agents go where on the FA/FI curve?

A

Nitrous Oxide (0.47)
Desflurane (0.42)
Sevo (0.69)
ISO (1.43)

58
Q

What 3 factors determine anesthetic uptake into the blood?

A
  1. Agent solubility
  2. Partial pressure difference between alveoli and blood
  3. Cardiac output
59
Q

Low solubility = (slower/faster) onset

High solubility = (slower/faster) onset

A

Low solubility = faster onset (less taken up by blood, more pressure in the alveoli/brain)
High solubility = slower onset (more taken up by blood, less pressure in the alveoli/brain)

60
Q

Why is the rate of rise of FA/FI faster for N20 then DES when des has a lower B:G coefficient?

A

Bc of the concentrating effect… sure…

Faster “wash-in”….

61
Q

What does FI stand for?

A

Inspired fraction of anesthetic (carried by the FGF - increased FGF = increased total amount carried)

62
Q

FA

A

Alveolar concentration of anesthesia

63
Q

2 main ways to increase FA/FI

A

Increase wash-in : high fresh gas flow, high alveolar ventilation, low FRC, low time constant, low anatomic dead space

Decrease uptake: low solubility, low CO, low Pa-Pv difference

64
Q

Hepatic Biotransfomration of Des, ISO, sevo, halothane, nitrous

A

Rule of 2s! (D-I-S)

Des- 0.02%
Iso- 0.2%
Sevo 2% - 5%
Halothane - up to 20%

Nitrous = 0.004 (2 zeroes + (2+2=4) - essentially not metabolized in the body

65
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

Low Pa-Pv difference

A

Decreases uptake

66
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

High anatomic dead space

A

Decreases wash-in

67
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

High FGF

A

Increases wash-in

68
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

High agent solubility

A

Increases uptake

69
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

High FRC

A

Decreases wash-in

70
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

High Cardiac output

A

Increases uptake

71
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

Low time constant

A

Increases wash-in

72
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

Low FGF

A

Decreases wash-in

73
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

Low agent solubility

A

Decreases uptake

74
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

High Pa-Pv difference

A

Increases uptake

75
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

High alveolar ventilation

A

Increases wash-in

76
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

Low FRC

A

increases wash-in

77
Q

Increases wash-in; Decreases wash-in; Increases uptake; Decreases uptake:

Low CO

A

Decreases uptake (which increases FA/FI)

78
Q

What does the Vessel Rich Group consist of? (5)

A

Brain, heart, liver, kidneys, endocrine organs

79
Q 
Cardiac output vs Body mass % of 
VRG
Muscle & Skin
Fat 
VPG (tendons, ligaments, cartilage, bone
A
80
Q

In what 2 ways are inhaled anesthetic eliminated from the body?

A
  1. Alveoli (primary)

2. Hepatic biotransformation (secondary)

81
Q

Important metabolites and associated risks of Des, ISO, sevo

A

Des & Iso > Trifluoroacetic acid > small risk of immune-mediated hepatic dysfunction

Sevo > free fluoride ions > theoretical risk of high output kidney failure

82
Q

What is the mechanism for halothane hepatitis?

A

High concentration of TFA (trifluroacetic acid) in the liver)

83
Q

What is characteristic of high output renal failure from sevo related to free fluoride ion production?

A

Unresponsiveness vasopressin

Polyuria, hypernatremia, hyperosmolarity, increased creat, inability to concentrate urine

84
Q

What toxic compounds from inhalational anesthetic are produced inside vs outside the body

A

Produced inside the body: TFA & free fluoride ions

Produced outside the body: Carbon monoxide (exposure to desiccated soda lime with iso and des)

85
Q

FDA guidelines regarding the minimum FGF you should use with sevo

A

FGF of 1L/min for up to 2-MAC hours
FGF of 2L/min after 2-MAC hours

2% sevo (1MAC) x 1 hour = 1 Mac hour
1% sevo (1/2 MAC) x 2 hours = 1 MAC hour

2% sevo (1 MAC) x 2 hours = 2 Mac hours
1% sevo (1/2 MAC) x 4 Mac hours = 2 MAC hours

86
Q

Which P450 enzyme is chiefly responsible for halogenated anesthetic metabolism in the liver?

A

CYP 2E1

87
Q

The higher the concentration of inhalation anesthetic delivered to the alveolus (FA), the faster its onset of action — term x 2

A 
Concentration effect (not concentrating)
Or over-pressurizing
88
Q

When a patient is breathing in room air, what is the primary gas being inhaled?

A

Nitrogen (78%)

89
Q

How much more soluble is nitrous oxide in the blood compared to nitrogen (in room air)

A

34x more soluble

90
Q

Explain the concentratING effect

A

Bc nitrous oxide is 34x more soluble in blood than nitrogen, when it is introduced into the lung,
>the volume of n20 going from the alveolus > pulmonary blood is much higher than the amount of nitrogen moving in the opposite direction (pulm blood > alveolus)
>this causes the alveolus to shrink, and the reduction in alveolar volume causes a relative increase in FA

(Explains why nitrous and not des achieves the fastest rate of rise of FA/FI)

91
Q

How does the 2nd gas effect work?

A

Bc nitrous oxide is 34x more soluble in blood than nitrogen, when it is introduced into the lung,
>the volume of n20 going from the alveolus > pulmonary blood is much higher than the amount of nitrogen moving in the opposite direction (pulm blood > alveolus)
>this causes the alveolus to shrink, and the reduction in alveolar volume causes a relative increase in FA of N20
(Concentrating effect)

> then you have reduced alveolar volume + augmented tracheal inflow with a second gas to replace that shrunken, nitrous filled alveolus, causing a relative increase in concentration of the 2nd gas (increased pressure bc of smaller alveoli ) — i could be making that up

92
Q

Gas containing areas of the body can absorb up to __L of N20 within 2 hours

A

30L

93
Q

Explain diffusion hypoxia - how can you prevent it?

A

So 30L of N20 can be absorbed into gas containing areas of the body within 2 hours
>when this massive amount of N20 is transferred out of the body and into the alveoli to be exhaled, it dilutes alveolar concentrations of o2 & CO2
>causing a temporary diffusion hypoxia and hypocarbia (decreased stimulus to breathe) -> can decrease PaO2 further

Prevent if by administering 100% FIO2 for 3-5 minutes after nitrous has been discontinued

94
Q

The rate of rise of FA/FI of which agent will be affected the most with a right to left shunt

A

Desflurane

95
Q

How does the concentration effect affect the rate of rise on the FA/FI curve?

A

The higher the concentration of inhalational anesthetic delivered to the alveolus, the faster its onset of action

96
Q

Jeopardy style: Changes in alveolar ventilation affect the rate of rise of FA/FI

A

What is: Ventilation effect

97
Q

Does the second gas effect have a more meaningful impact on iso or sevo? Why?

A

Iso bc of it’s higher blood:gas solubility

Iso>sevo>des

98
Q

A right to left cardiac shunt (slows/speeds) induction with a volatile agent.

A

Slows (some blood isn’t going to the lungs to pick up the inhalational agent in the lungs + dilutes the blood that did pick up the inhalational agent)

99
Q

Inhalational induction is slower with volatile agents in pts with right to left shunts. Agents with (low/high) solubility are affected the most & agents with (low/high) solubility are affected the least

A

Low solubility affected the most (des) (likes to stay in lungs and the blood is bypassing them- will notice the greatest impact with these agents)

High solubility affected the least - wont notice as big of a difference, will still take long

100
Q

Right to-left shunt: (slower/faster) induction with IV agents

A

Faster (bypasses the lungs goes right to systemic)

101
Q

Left-to-Right shunt: (faster/slower) induction with IV agents

A

Slower (keeps going back to right side and not out to systemic)

102
Q

T/F: in patients with a left-to-right shunt, there is no meaningful impact on induction with a volatile anesthetic

A

True

103
Q

5 Examples of Right to Left shunts

A

“To the left, to the left — move your FEETT”

Foremen ovale
Eisenmenger’s Syndrome (think Alexa Eisen is Right winged, R>L shunt
Ebstein’s anomaly (Think Alexa eisen, conspiracy theorist like the rest of us, Epstein conspiracy)
Tetralogy of fallot
Tricuspid atresia

104
Q

The blood:gas partition coefficient MOST closely correlates with: speed of emergence, vapor pressure, biotransformation, potency

A

Speed of emergence

105
Q

What partition coefficient is related to potency

A

Oil:Gas

106
Q

Potency is (directly/inversely) proportional to MAC

A

Inversely

-decreased potency, higher MAC (takes more to achieve Mac)

107
Q

Which anesthetic agent undergoes the GREATEST degree of elimination from the lungs?

A

Desflurane

> the greater amount of agent metabolized by the liver, the less is eliminated from the lung
des undergoes the least metabolism from the liver (0.02%), so it’s elimination from the lung is the greatest

108
Q

Which anesthetic agents bear the closest chemical resemblance?

A

Iso & Des

Iso has a chlorine molecule and des has a fluorine instead

109
Q

What occurs when a liquid’s vapor pressure equals atmospheric pressure?

A

Boiling

110
Q

Oil:Gas coefficient of Sevo, Des, Iso

A

ISO 100
Sevo 50
Des 20

*Pharmacology (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions