Exam 2: Basic Pharmacology of Anesthetics Flashcards Preview

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Flashcards in Exam 2: Basic Pharmacology of Anesthetics Deck (83):
1

What functions are impaired in minimal sedation/anxiolysis?

Cognitive
Coordination

2

What additional functions are impaired in moderate/conscious sedation?

Level of awareness; pts respond purposefully to verbal command

3

What additional functions are impaired in deep sedation?

Level of awareness; pts respond purposefully to pain stimulus

Airway/ventilatory function (may need assistance)

4

What additional functions are impaired in general anesthesia?

Level of awareness (nonresponsive)

Airway/ventilatory function (will need airway assistance)

Cardiovascular function

5

Define general anesthesia:

Generalized, reversible central nervous system depression

6

Four characteristics of general anesthesia:

No sensory perception
Loss of consciousness
No recall of events
Immobility

7

Seven types of drugs used in general anesthesia:

Pre-op/sedation
Induction
NMB
Inhalational
Opioids/LA
Antiemetic
Reversal

8

Prototype benzodiazepine:

Diazepam

9

5 effects of all benzos:

Anxiolysis
Sedation
Anterograde amnesia
Anticonvulsant
Muscle relaxation

10

At what level do benzos cause muscle relaxation?

Spinal level

11

Benzo mechanism of action:

Potentiates binding of GABA to receptor

Increases GABA potency 3x

12

What changes do benzos cause in the neuronal membrane?

Increased Cl- influx
Hyperpolarization
Decreased excitability

13

During what perioperative stage(s) are benzos used? Why?

Pre-operative; very long half-life

14

Adverse effects of benzos:

Ventilatory decrease, especially with opioids; potential hypoxemia

Decreased SVR (high dose) and resulting hypotension

15

Contraindication(s) for benzos:

Pregnancy

16

At what level(s) do opioids suppress pain?

Spinal and supraspinal

17

What system do opioids activate?

Endogenous pain suppression system

18

Opioid mechanism of action:

Agonist at stereospecific opioid receptors

Increased K+ outflow - hyperpolarization

Ca++ channel inactivation

19

Where are the receptors that opioids affect?

Pre- and post-synaptic sites in the brainstem, spinal cord, and peripheral tissues

20

During which perioperative stage(s) are opioids used?

All of them

Pre-medication
Intra-op pain management
General anesthesia
Post-op pain management

21

Adverse effects of opiates:

Bradycardia
Respiratory depression
Miosis
Urinary retention
Constipation
Dependence
Sedation

22

Characteristics of opioid-induced respiratory depression:

Rate decreases
TV increases (but not enough to overcome)

23

Barbiturate mechanism of action:

Decreases rate at which GABA dissociates from receptors (prolongs Cl- channel opening)

Mimics GABA (activates Cl- channels)

24

What system do barbiturates depress?

Reticular activating system (thus inducing sleep)

25

Prototype barbiturate drug:

Thiopental

26

Anesthetic uses of barbiturates:

Sedation/hypnosis
Cerebral protection
Anticonvulsive
Induction of GA

27

In which patients is a barbiturate induction beneficial?

Pts with increased ICP or focal brain ischemia

28

Are benzos or barbiturates more effective anticonvulsants?

Benzos

29

Adverse cardiopulmonary effects of barbiturates:

SNS depressant (peripheral vasodilation, BP/CO decrease)
Ventilatory depression

30

Under what circumstances will barbiturates cause significant cardiac depression?

SNS not intact
Hypovolemia
Large doses

31

What occurs if barbiturates are injected intra-arterially?

Very high pH (10-11) - drug precipitates quickly if injected arterially, causes vasoconstriction, gangrene, nerve damage

32

Adverse metabolic effects of barbiturates:

Potent hepatic enzyme inducers

Accelerates production of heme

33

Drugs that barbiturates increase the metabolism of:

Muscle relaxers
Oral anticoagulants
Phenytoin
TCAs
Corticosteroids
Vitamin K

34

What condition is a strong contraindication to use of barbiturates?

Porphyria

35

Barbiturate allergies:

1 in 30,000
High mortality

36

Barbiturates and pregnancy:

Readily crosses the placenta

37

Propofol is supplied as:

1% solution in egg, soy, glycerol base

38

Preservatives used in propofol and related caution:

EDTA
Sodium metabisulfite - can cause rxn in asthmatics

39

Special care in drawing up propofol:

Highly susceptible to contamination

All vials are single-use; do not spike a bottle twice

40

Propofol mechanism of action:

Potentiates binding of GABA to B1 subunit of receptor

Decreases rate of GABA dissociation from receptor

41

Effects (5) of propofol:

Sedation/hypnosis
Antiemetic
Antipruritic
Anticonvulsant
Reduction in bronchoconstriction

42

Anesthetic uses of propofol:

IV sedation
Induction
Maintenance (TIVA)
Part of maintenance (combined technique)
Antiemetic

43

Consideration with injection of propofol:

Very painful - use lidocaine + opioid before propofol

44

Cardiopulmonary effects of propofol:

Ventilatory depression
Myocardial depression
Vasodilation
No reflex tachycardia (baroreceptor inhibition)

45

Muscular/tissue/hematologic effects of propofol:

Myoclonus (esp. with large induction doses)
Painful injection
Lipidemia with long-term infusion

46

Pre-synaptic events at the neuromuscular junction:

1. Action potential depolarizes nerve terminal
2. Ca++ channels open
3. Ca++ diffuses down gradient to nerve terminal
4. ACh spills into synaptic cleft

47

Post-synaptic events at the neuromuscular junction:

1. ACh combines with nicotinic receptors (both must be occupied)
2. Na+, Ca++ diffuse into cell, K+ diffuses out
3. Motor end plate depolarizes
4. Action potential
5. Contraction

48

Structure of ACh receptor:

5 protein subunits
Central cation channel

49

Which subunits on the ACh receptor must be bound to ACh to activate it?

Both alpha subunits

50

Succinylcholine class:

Depolarizing neuromuscular blockade

51

Succinylcholine mechanism of action:

Binds to nicotinic receptors

Causes a single contraction then muscles stay relaxed until drug diffuses back into circulation

52

Metabolism of succinylcholine:

Plasma esterases - NOT acetylcholine esterases in the synapse

53

Anesthetic uses of succinylcholine:

Optimize intubating conditions
RSI
Treatment of laryngospasm

54

Adverse effects of succinylcholine:

Cardiac dysrhythmias
Hyperkalemia
Muscle pain
Increased ICP, IOP
MH triggering agent

55

Conditions that predispose pts to hyperkalemia with succs:

Burns
Trauma
Nerve damage
Neuromuscular disease
Renal failure

56

Pts that should not receive succinylcholine:

Atypical acetylcholinesterase
Head injury patients

57

Vecuronium class of drugs:

Non-depolarizing muscle relaxant

Monoquaternary aminosteroid

58

Vecuronium mechanism of action:

Competitive antagonist at pre- and post-synaptic ACh receptors (occupies alpha subunit without conformational change)

59

Anesthetic uses for vecuronium:

Facilitate intubation
Optimize surgical conditions (abdominal surgeries)

60

Condition(s) that make effects of vecuronium prolonged/unpredictable:

Liver/kidney disease
Neuromuscular disease
Hypothermia
Electrolyte imbalances
Aminoglycoside antibiotics

61

Condition(s) that make patients resistant to vecuronium:

Burns

62

Signs of residual neuromuscular blockage:

"Floppy fish" appearance
TOF twitches not equally strong

63

Isoflurane class of drug:

Inhalational anesthetic

Halogenated methyl ethyl ester

64

What characteristic of isoflurane determines onset, duration, etc?

Lipid solubility

65

Isoflurane eliminated almost entirely via:

Lungs

66

Contemporary inhaled anesthetics eliminated via:

Minimal hepatic metabolism and renal excretion

67

Anesthetic uses of isoflurane:

Bronchodilation
General anesthesia (maintenance - Sevo best for induction)

68

Adverse effects of isoflurane:

Respiratory depression
Cardiac depression/vasodilation
Malignant hyperthermia

69

Physiology of malignant hyperthermia:

Ca++ channel interference
Muscle rigidity
Increased temperature
Increased CO2

70

Characteristics of isoflurane respiratory depression:

Increased rate
Decreased volume

71

Define MAC:

Mean alveolar concentration

Concentration at which 50% of patients do not move to noxious stimulus

72

MAC of isoflurane:

1.2%

73

MAC of nitrous oxide:

104%

74

Local anesthetic mechanism of action:

Inhibits Na+ channels during inactivated closed state and blocks impulse conduction during depolarizing phase

75

Prototype local anesthetic:

Lidocaine

76

Pharmacologic effects of local anesthetics:

Block afferent nerve transmission; analgesic/anesthesia without effect on consciousness

77

Three modalities that local anesthetics block:

Autonomic
Somatic sensory
Somatic motor

78

Classification of lidocaine:

Amide local anesthetic

79

Structure of local anesthetic molecule:

Lipophilic head (aromatic ring)
Intermediate chain (amide NH or ester COO-)
Hydrophilic tail (tertiary amine)

80

CNS s/s of local anesthetic toxicity:

Circumoral/tongue numbness, tinnitus, vision changes
Dizziness, slurred speech
Restlessness
Seizure
CNS depression
Apnea
Hypotension

81

Cardiac s/s of local anesthetic toxicity:

Hypotension
Myocardial depression
Reduced SVR/CO

82

Cardiac s/s of bupivicaine toxicity:

Arrythmias
AV heart block
Hypotension
Arrest

83

Cardiac s/s of cocaine toxicity:

Massive SNS outflow
Coronary vasospasm
MI
Dysrhythmias (v-fib)