Inhalational Anesthesia Flashcards Preview

Brain and Behavior Part 2 > Inhalational Anesthesia > Flashcards

Flashcards in Inhalational Anesthesia Deck (29)
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1
Q

Can nitrous oxide alone be used as a general anesthetic?

A

No, but it can be when combined with things such as opioids.

2
Q

How do isoflurane, desflurane, and sevoflurane relate molecular-ly to diethyl ether? One important functional property that sets them apart?

A

They are fluorinated / halogenated diethyl ether derivatives (or very similar structures, at least). Unlike ether, they aren’t flammable, which is important when using electrocautery in the OR.

3
Q

What are 4 clinically relevant differences between inhaled anesthetic agents?

A

Potency
Solubility
Pungency
Cost

4
Q

What are 5 things that you want your general anesthetic to do?

A

Hypnosis
Amnesia
Immobility / Muscle Relaxation / Akinesia
Blunting of Autonomic Responses

5
Q

What kinetics for inhaled anesthetics are desirable?

A

Quickly induce anesthetic state, but be readily reversed when the gas is removed.

6
Q

What effects do inhaled anesthetics have on brain metabolism? How about on synchrony?

A
Decreased metabolism.
Increased synchrony (like sleeping?).
7
Q

How do you achieve a controlled, constant dosage of inhaled drug being delivered to the patient?

A

By a vaporizer. (not an ether-soaked cloth)

8
Q

What are the 3 compartments into which anesthetic will go? Which can hold the most drug?

A

Vessel Rich Group (Brain, liver, kidney)
Fat (biggest, lowest blood flow)
Muscle (intermediate blood flow)

9
Q

How are anesthetic gases eliminated from the body?

A

By exhalation, mainly. Very little metabolic breakdown.

10
Q

What variable that varies between tissue types greatly affects absorption?

A

Solubility. Inhaled drugs tend to be highly soluble in fat and less soluble in brain.

11
Q

How does solubility in fat affect recovery time?

A

Less soluble in fat, less recovery time.

12
Q

Three reasons why anesthetic gases that are less soluble perform better?

A

Less potent - (better? worse? unclear)
Faster onset / “offset”
Less accumulation in tissue / fat

13
Q

How do inhaled anesthetic drugs affect cerebral blood flow?

A

They increase it.

14
Q

Is the spinal cord affected by inhaled anesthetics?

A

Yes. Response to stimuli is blocked.

15
Q

4 effects of inhaled anesthetics on respiration?

A

Bronchodilation
Increased respiratory rate
Decreased tidal volume
Decreased respiratory reflexes (i.e. RR won’t increase in response to low O2 / high CO2)

16
Q

4 cardiovascular effects of inhaled anesthetics?

A

Decreased BP (vasodilation)
Blood redistributed from core to periphery (vasodilation)
Impairs autonomic reflexes to maintain BP (eg. carotid baroreceptor reflex)
Decreases contractile strength of heart muscle.

17
Q

What’s the MAC? How is it used?

A

Minimum Alveolar Concentration: % of total gas that must be anesthetic in order to make 50% of patients not move in response to surgical incision.
Used as a starting point from which the dosage is adjusted for the patient.

18
Q

3 factors other than MAC affecting the proper dose of inhaled anesthetic?

A

Intensity and type of surgical stimulus.
Age and medical condition of patient.
Concurrent use of other anesthetics (opioids, muscle relaxants).

19
Q

What are 4 common problems with inhaled anesthesia?

A

Nausea and vomiting
Respiratory depression
Cardiovascular collapse
Inhibition of uterine contraction (post-delivery bleeding)

20
Q

2 rare complications seen with inhaled anesthetics?

A

Malignant hyperthermia

Liver toxicity

21
Q

1 controversial problem with anesthesia?

A

Neurotoxicity.

22
Q

Are patients the only people who might be adversely affected by inhaled anesthetics?

A

No. They might harm the environment, esp. the ozone layer. (how about anesthesiologists, surgeons, nurses, and techs?)

23
Q

What’s the mechanism of action of inhaled anesthetics?

A

Trick question. Nobody knows.

24
Q

What’s the functional outcome of inhaled anesthetics, broadly speaking?

A

Disrupt normal patterns of neuronal transmission involved in consciousness, which we see on EEG.

25
Q

What does the fact that that these gases work on flies, snakes, fish, and zebras tell us?

A

It works on evolutionarily ancient, conserved machinery.

26
Q

What do we know about where, cellularly speaking, these drugs go?

A

They like membranes. It’s probably more about binding to proteins than altering membrane properties, though.

27
Q

Is there just one receptor that inhaled anesthetics bind to?

A

No. They seem to bind to many.

28
Q

Is there thought to be one receptor to which anesthetic gas binding is most important?

A

Yes. GABA-A appears to be pretty important.

29
Q

Why are there suspicions that anesthetic gases pose cognitive risks?

A

Some animal models suggest reduced synapse formation after exposure.
Many anecdotal reports of “not feeling like self” after general anesthesia.