Brainscape's Knowledge GenomeTM

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


See full index

Pharmacology II > General Anesthetics > Flashcards

General Anesthetics Flashcards

1
Q

where do many anesthetics act?

A

At GABA synapses on postsynaptic membranes by inhibiting propagation of further action potentials

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

How do barbiturates affect GABAa channels?

A

Make them stay open longer, allowing more Cl- in and hyperpolarizing cell

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

what are the three types of glutamate receptors upon which anesthetics act?

A
  • AMPA
  • Kinate
  • NMDA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is MAC?

A

minimum alveolar concentration

50% jump off the table

50% don’t jump off the table

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

At 1.3 MAC, what happens?

A

99% of patients are immobile (not jumping off the table)

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

what is a typical induction dose of volatile anesthetic?

A

2.0 MACs

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

what has a faster response, an agent with a low partition coefficient or an agent with a high partition coefficient?

A

low partition coefficient (low solubility)

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

does nitrous oxide have a low or high partition coefficient?

A

low

on and off fast

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

what are the key things about halothane?

A
  • blood:gas 2.3 - relatively high, induction slow
  • soluble in fat
  • Cons: immune response to halothane (halothane hepatitis - immune response evoking hepatic necrosis, fever, nausea, rash and vomiting)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is important to know about methoxyflourane?

A
  • it really is not used much anymore
  • very potent - high blood:gas partition, so long induction and emergence
  • highly soluble in rubber, so can’t have rubber tubing
  • extensive metabolism
  • may produce renal failure and nephrotoxicity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the key things to know about nitrous oxide?

A
  • can’t acheive unconsciousness with it
  • rapid induction and emergence
  • analgesic primarily
  • 70-80% in 02
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is malignant hyperthermia?

A

rare hertiable disorder triggered by volatile anesthetics and some neuromuscular blockers caused by an inability of the SR to sequester Ca2+

reaction causes massive pyrexia after exposure

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

What is key to know about propofol?

A

Pros:

  • rapid metabolism and recovery
  • little accumulation
  • “milk of amnesia” - hypnotic and forgetful rest

Cons:

  • pain on injection
  • not water soluble (more difficult handling)
  • no antagonist
  • no analgesia
  • cardiorespiratory depression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is key to know about etomidate?

A
  • Pros
    • antagonist available
    • anterograde amnesia
    • cardiovascular stability - does not cause hypotension
  • Cons
    • pain on injection
    • no analgesia
    • accumulates - slowing recovery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What patient populations must you be extra cautious about with anesthetics?

A
  1. Trauma even if the drug shows minimal hypotensive s/e, due to volume depletion in most trauma patients
  2. Elderly
  3. Cardiorespiratory Disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which preanesthetic medications are used to reduce anxiety and induce amnesia?

A

Benzodiazepenes

Midazolam (Versed)

Diazepam (Valium)

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

Which preanesthetic is used to prevent allergic reactions and provide some sedation?

A

antihistamines (1st gen)

diphenhydramine (Benadryl)

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

What preanesthetic drug is typically given to prevent aspiration and postsurgical nausea and vomiting?

A

Ondansetron (5HT3 antagonist) - Zofran

anti-emetic

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

What preanesthetic is given to provide analgesia?

A

opioids

morphine

Fentanyl

20
Q

what preanesthetics are given to prevent bradycardia and to dry up secretions?

A

antimuscarinics

scopolamine, atropine

21
Q

What preanesthetic is given as a muscle relaxant to facilitate intubation?

A

pancuronium

22
Q

What is key to know about Ketamine?

A

Pros:

  • analgesia
  • No respiratory depression - may INCREASE BP
  • produces hypnotic state
  • adverse effects uncommon in children (favorite in pediatrics)

Cons:

  • increased muscle tone and incidence of involuntary tics or jerks
  • hallucinations
23
Q

What is important to know about sodium thiopental (barbiturate)

A

Pros:

  • little post-anesthetic excitement or vomiting
  • water soluble

Cons:

  • respiratory and CV depression
  • no antagonist
  • slow recovery
  • no analgesia
24
Q

What are some of the key characteristics of IV anesthetics?

A
  1. rapid onset (seconds)
  2. rapid awakening (minutes)
  3. danger of overdose due to irrevocability of IV injection
  4. redistribution determines duration of action
  5. acts in the vessel-rich group rapidly (CNS and visceral organs)
25
Q

how do benzodiazepenes act on GABA channels?

A

they increase the affinity of GABA for its binding site on the GABA(A) receptor

26
Q

What happens at 0.3 MAC?

A

mild anesthesia begins

27
Q

what happens at 0.5 MAC

A

amnesia begins

28
Q

What does the dose-response curve with general anesthetics typically look like?

A

usually, it is very steep (low TI)

29
Q

What happens at doses higher than 2.0 MAC?

A

potentially lethal doses

30
Q

how is MAC often expressed?

A

as a % needed of the anesthetic in air to get 1 MAC

31
Q

What is the Meyer-Overton correlation?

A

The potency of an anesthetic is directly proportional to the Log10(lipid bilayer/water partition coefficient)

in other words, more lipid soluble = more potent

32
Q

Which anesthetics act primarily by enhancing activity of GABA(A) receptors?

A

etomidate

propofol

barbiturates

isoflurane

sevoflurane

(i.e., most of them)

33
Q

Which anesthetics act primarily by inhibiting NMDA glutamate receptors?

A

ketamine

nitrous oxide (also acts at kainate glutamate receptors)

34
Q

transfer of anesthetic from the lungs to the arterial blood depends upon _________

A

the solubility of the drug in the blood

35
Q

low partition coefficients have low or high solubility?

A

LOW

36
Q

the speed of induction is inversely proportional to what ratio?

A

blood:gas partition coefficient

37
Q

time course of action of anesthetics depends upon solubility and what else?

A

distribution of the anesthetic in different tissues

agents more soluble in fat have a longer equilibrium and longer on/off time

38
Q

a larger fat:blood partition coefficient means that an anesthetic will _________?

A

remain dissolved in the fat for longer

39
Q

Is enflurane low or high blood:gas soluble and metabolised?

A

1.8, relatively high solubility and high metabolism

induction and emergence are slow

40
Q

what are the disadvantages of enflurane?

A
  • cardiovascular depression due to decreased cardiac contractility
  • seizures - no permanent damage
  • uterine muscle relaxant
41
Q

What are key things to know about Isoflurane?

A
  • most commonly used inhalation anesthetic in U.S.
  • 1 MAC =1.4%
  • blood:gas = 1.4, relatively low, somewhat rapid induction
42
Q

What are the pros and cons of isoflurane?

A

Pros

  • cardiac output maintained
  • systemic vessels dilate causing small decrease in BP
  • arrhythmias uncommon
  • potent coronary vasodilator

Cons

  • more pungent than haloethane
  • progressive respiratory depression
43
Q

what are the properties of sevoflurane?

A

blood:gas - 0.69

relatively low, fast induction

44
Q

What are the pros and cons of sevoflurane?

A

Pros:

  • can be used for outpatient because of its rapid on/off

Cons:

  • some reports of toxicity
45
Q

what are the properties of desflurane?

A

blood:gas 0.42

low, very fast induction and emergence (5-10 minutes)

46
Q

What are the pros and cons of desflurane?

A

Pros:

  • useful for outpatient surgery
  • not very soluble in fat

Cons:

  • more irritating to airway - can provoke coughing, salivation and bronchospasm
  • low volatility - requires use of specially heated vaporizer
  • may evoke tachycardia
47
Q
A

Pharmacology II (11 decks)

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