Neuro Exam 2: General Anesthesia

Front 1

What is general anesthesia?

Back 1

a drug-induced LOC in which pts are not arousable, even by painful stimulation

Front 2

Explain the steps in the spectrum of consciousness.

Back 2

awake --> minimal sedation (anxiolysis) --> moderate sedation --> deep sedation --> GA

Front 3

What are the major stages in GA?

Back 3

Premedication
Induction
Maintenance
Emergence

Front 4

What is emergence?

Back 4

reversal of neuromuscular blockade, anti-emetic, analgesia

Front 5

What is important in the maintenance phase of GA?

Back 5

sedative/hypnotic, analgesia, autonomic stabalization

Front 6

What is important in the induction phase of GA?

Back 6

sedative/hypnotic, analgesia, muscle relaxation

Front 7

What is important in the premedication phase of GA?

Back 7

anxiolysis, antisalagogue, autonomic stabilization, analgesia

Front 8

What is the mechanism of action of inhalation anesthetics?

Back 8

it is LARGELY unknown (but probably something to do w/ inhibition of glutamate receptors and increased activity of GABA receptors)

Front 9

What affects the pharmacokinetics of inhaled anesthetics?

Back 9

CO and ventilation rate

Front 10

What determines the clinical effect of inhaled anesthetics?

Back 10

partial pressure of volatile anesthetic at the CNS

Front 11

What are the major pharmacokinetic principles of inhaled anesthetics?

Back 11

Absorption/Uptake (from alveoli to systemic circ)
Distribution
Metabolism/Biotransformation
Excretion/Elimination from the lungs

Front 12

What determines the transition from the vaporizer to tissue?

Back 12

Series of partial pressure gradients

Front 13

What is the key determinant of anesthetic uptake into the blood and distribution t/o the body?

Back 13

solubility

Front 14

__ agents have fast rise in alveolar concentration b/c they are not easily taken up by the blood

Back 14

insoluble (like nitrous)

Front 15

There is a __ relationship b/w blood solubility and rate of induction

Back 15

inverse

Front 16

T or F: Breathing and cardio systems are impaired in GA

Back 16

TRUE

Front 17

What is anxiolysis?

Back 17

taking the edge off

Front 18

Hyperventilation __ rate of anesthetic onset

Back 18

increases

Front 19

___ slows rate of anesthetic onset

Back 19

hypoventilation

Front 20

What are the 4 cornerstones of GA?

Back 20

LOC
Amnesia
Analgesia
Muscle relaxation

Front 21

What are some classes of inhalational anesthetics?

Back 21

Ether, N2O, halogenated hydrocarbons

Front 22

Less soluble -->

Back 22

faster onset of action

Front 23

More soluble -->

Back 23

slower onset of action

Front 24

Anesthetics that depress ventilation __ the rate of rise of alveolar concentratoin and create a negative feedback loop.

Back 24

decrease

Front 25

Higher CO/PBF --> __ alveolar partial pressure

Back 25

lowers

Front 26

__ relationship b/w CO/PBF and rate of induction

Back 26

inverse

Front 27

What are partition coefficients?

Back 27

the relative solubility of an anesthetic in air, blood, or tissue.

Front 28

Transfer from blood to tissue depends on __ and __ of gas in different tissues

Back 28

perfusion and solubility

Front 29

T or F: Areas w/ less blood flow have slower rate of rise of tissue gas concentration

Back 29

TRUE

Front 30

Which agent undergoes the greatest metabolism in the CYP P-450 system?

Back 30

halothane

Front 31

metabolism of halogenated anesthetics to free inorganic fluoride -->

Back 31

nephrotoxicity

Front 32

The majority of elimination occurs at the __

Back 32

alveolus

Front 33

Recovery from anesthesia depends on what?

Back 33

lowering the conc of anesthetic in brain tissue

Front 34

What is MAC?

Back 34

Minimum Alveolar Concentratoin of inhaled anesthetic that prevents movement in 50% of pts in response to a surgical stimulus

Front 35

T or F: MAC compares the potency of agents

Back 35

TRUE
The lower the MAC, the more potent the drug

Front 36

T or F: MAC values are additive

Back 36

TRUE

Front 37

What is the most insoluble agent?

Back 37

Nitrous oxide

Front 38

T or F: All agents cause dose-dependent myocardial depression (decreased contractility)

Back 38

TRUE

Front 39

What is the classic breathing response to GA agents?

Back 39

Increased RR and Decreased TV

Front 40

Which agent stimulates the SNS (by catecholamine release)?

Back 40

Nitrous oxide

Front 41

Why do you avoid nitrous oxide in pts w/ air containing cavities?

Back 41

b/c it is 25 times more soluble than nitrogen in blood and moves into and expands these spaces

Front 42

Which agent inhibits B12 dependent enzymes?

Back 42

N2O

Front 43

Which agent is the most potent bronchodilator?

Back 43

halothane

Front 44

Which agent causes reflex tachycardia?

Back 44

isoflurane

Front 45

which agent irritates upper airway reflexes, but is a potent bronchodilator?

Back 45

isoflurane

Front 46

Which agent has a low solubility in blood and tissue and low blood/gas partition coefficient which makes it good for fast onset and recovery?

Back 46

desflurane

Front 47

Which agent is a pungent, potential airway irritant?

Back 47

desflurane

Front 48

Which agent is nonpungent and has rapid increase in alveolar concentration making it good for mask induction?

Back 48

sevoflurane

Front 49

What causes malignant hyperthermia?

Back 49

mutation in ryanodine receptor Ryr1 in skeletal muscle

Front 50

What is malignant hyperthermia?

Back 50

uncontrolled Ca release from skeletal muscle triggered by volatile anesthetics leading to sustained muscle contractions producing a hypermetabolic response

Front 51

What is the major inhibitory NT in the CNS?

Back 51

GABA

Front 52

What is Ketamine?

Back 52

NMDA receptor antagonist (subtype of the glutamate receptor)

Front 53

Which agent is a "dissociative" anesthetic?

Back 53

ketamine

Front 54

What is a dissociative anesthetic do?

Back 54

dissociates the thalamus from the limbic cortex

Front 55

What is ketamine used for?

Back 55

central stimulation of SNS cause CV stability, maintained ventilatoin, increased CBF, ICP, CMRO2

Front 56

What does etomidate do?

Back 56

depresses the RAS and mimics inhibitory effects of GABA

Front 57

What is a side effect of etomidate?

Back 57

myoclonus (disinhibits the extrapyramidal motor activity) and adrenocortical suppression

Front 58

T or F: Propofol has a rapid onset and recovery

Back 58

TRUE

Front 59

How does dexmedetomidine work?

Back 59

lipophylic alpha-methylol derivative w/ a high affinity for the alpha-2 receptor

Front 60

HTN w/ rapid administration --> which drug

Back 60

dexmedetomidine

Front 61

Which drug can cause hypotension and bradycardia during ongoing therapy?

Back 61

dexmedetomidine

Front 62

T or F: Neuromuscular blockade contributes to the depth of anesthesia

Back 62

FALSE

Front 63

What is NMJ blockade used for?

Back 63

facilitate tracheal intubation
improves surgical condition and surgical exposure
prevents potential movement during critical surgical interventions
DOES NOT CONTRIBUTE TO ANESTHESIA

Front 64

__ are quaternary ammonium compounds w/ affinity for nicotinic ACh receptors due to positively charged N.

Back 64

neuromuscular blockers

Front 65

Which drug closely resembles ACh generateing muscle APs?

Back 65

succinylcholine

Front 66

What are the two classes of neuromuscular blockers?

Back 66

depolarizing and non-depolarizing

Front 67

What is an example of a depolarizing neuromuscular blocker?

Back 67

succinylcholine

Front 68

What are some non-depolarizing neuromuscular blockers?

Back 68

pancuronium, cisatracurium, vecuronium, rocuronium

Front 69

T or F: succinylcholine is metabolized by acetylcholinesterase.

Back 69

FALSE

Front 70

agonist or antagonist: succinylcholine

Back 70

ACh agonist

Front 71

How do non-depolarizing neuromuscular blockers work?

Back 71

bind ACh receptors but are incapable of opening ion channels <--> they are competitive antagonists

Front 72

How are depolarizing NMBs reversed?

Back 72

they diffuse from NMJ and are hydrolyzed in plasma and liver by pseudocholinesterase

Front 73

Which inhaled agent has a dose-dependent reduction of arterial blood pressure and direct myocardial depression?

Back 73

halothane

Front 74

what is a serious complication of halothane?

Back 74

hepatitis

Front 75

___ sensitizes the heart to the arrhythmogenic effects of epi

Back 75

halothane

Front 76

Which agent has minimal cardiac depression w/ mild beta-adrenergic stimulation?

Back 76

isoflurane

Front 77

Which drug gives elevation in HR, BP and catecholamine release with a rapid increase in concentration?

Back 77

desflurane

Front 78

Which agent directly dilates the cerebral vasculature leading to increased CBF and ICP?

Back 78

desflurane

Front 79

How do you treat malignant hyperthermia?

Back 79

Dantrolene Sodium and supportive care

Front 80

How are most GA agents administered?

Back 80

IV

Front 81

Which nonvolatiles agent may suppress adrenocortical function?

Back 81

etomidate

Front 82

Which nonvolatile agent can give myoclonus?

Back 82

etomidate

Front 83

Which nonvolatile agent is distributed in an oil-water immersion making it susceptible to bacterial growth? It also causes substantial pain on injection.

Back 83

propafol

Front 84

What is propafol approved for?

Back 84

moderate-deep sedation and GA (induction and maintenance)

Front 85

Which nonvolatile agent is a lipophilic alpha-methyol derivative with a high affinity for the alpha-2 receptor?

Back 85

dexmedetomidine

Front 86

How do you reverse nondepolarizing NMBs?

Back 86

cholinesterase inhibitors increase ACh at NMJ and compete with them.

Front 87

What are some anticholinesterase drugs?

Back 87

Neostigmine, Pyridostigmine, Physostigmine, Edrophonium

Front 88

Why do you give an anticholinergic when you give an anticholinesterase?

Back 88

to minimize the muscarinic effects and maximize the nicotinic effects

Front 89

What are some "antimuscarinics" (i.e. anticholinergics)?

Back 89

atropine, scopolamine, glycopyrolate

Front 90

Muscarinic -->

Back 90

sympathetic

Front 91

Nicotinic -->

Back 91

parasympathetic