N16/17 - Anesthetics (Zhu) Flashcards Preview

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Flashcards in N16/17 - Anesthetics (Zhu) Deck (85):
1

Types of local anesthetics (chemical property)

Esters

Amides

2

local anesthetic that mainly exists in neutral form (pka 3.5)

Benzocaine

3

hydrophobicity of most effective LAs

moderate

4

2 changes due to binding of LA to binding site

occlusion

restriction of conformational change

 

- AP generation is blocked (prevented channel opening)

- AP conduction is blocked (prolonged refractory period)

5

modulated receptor hypothesis

Low binding affinity at resting state

 

High binding affinity at:

- intermediate closed state

- open state

- inactivated state: LA stabilizes channel in innactivated state, channel cannot be reopened even after repolarization

6

channel states when LAs have major effect

Intermediate closed - prevents opening

Inactivated - extends refractory period

7

attenuates effectiveness of LAs

hypocalcemia - increased Na excitability

8

Potentiates the effectivenss of local anesthetics

Hyperkalemia - membrane is persistently depolarized

9

General blockade order

First pain

Second pain

Temperature

Touch, proprioception (pressure, position, stretch)

Motor function

10

blocks pain, without significant motor block

Epidural bupivacaine

11

A-gamma fibers

muscle tone

12

A-delta fibers

First pain & temperature

13

C fibers

second pain & temperature

14

to avoid systemic absorption of LAs

co-administration of vasoconstrictors

15

Co-administered vasoconstrictor:

Except in which areas?

epinepherine

 

Except in: fingers, toes, ears, nose, penis

16

Pain relief

oral, nasal, laryngeal, rectal disorders, surgery

Topical: Mucous membrane application

17

Tx: pruritus

poison ivy, insect bites, eczema, venipuncture, chickenpox, etc

topical anesthesia: skin application

18

suturing wounds

removal of foreign bodies

dental procedures

Infiltration LA - intradermal or subq

Lidocaine, procaine, bupivacaine

19

toxicity due to 

systemic absorption

20

systems affected by LA toxicity

CNS - excitement followed by depression (inhibition of inhibitory pathways, then both excite & inhib)

Cardiovascular - vasoconstriction, then vasodilation

21

Acts as antiarrhythmic at very low concentration

Lidocaine

22

hypersensitivity

Ester-type LAs

met. product = p-aminobenzoic acid (PABA)

23

cautioned use for potentiation of neuromuscular blockers

Myasthenia gravis

(use great caution)

24

Vasoconstriction

cardiotoxicity

CNS stimulation

Tx: opthalmic, nasal surgery (blocks bleeding), topical

Cocaine

(Ester-type)

25

nasal surgery

Cocaine

26

No topical application

Procaine (Novocain)

Chloroprocain (Nesacaine)

(Ester-type)

27

High hydrophobicity

Fast onset

High potency

Long acting

Spinal & topical

Tetracaine

(Ester-type)

28

Weak

Used in nonprescription topicals

Benzocaine

(Ester-type)

29

Risk for hypotension & cardiotoxicity

Bupivacaine

30

Similar to bupivacaine

less cardiotoxicity

Levobupivacaine

Ropivacaine - structural analog

Mepivacaine - structural analog

(Amide-type)

31

Amide-type drugs - name hint

2 I's

32

Ester-type drugs: name hint

1 "I" in name

33

Topical & infiltraion anesthesia

Prilocaine

34

Infiltration and nerve block anesthesia

Etidocaine

35

Amide-type with ester group

dental procedures

Articaine

36

Lidocaine + Prilocaine combo

Topical - Venipuncture, lumbar, dental

EMLA (Eutectic mixure of local anesthetic)

37

Contain halogens in chemical structure

Inhaled anesthetics

(except nitrous oxide)

38

Contain ether bond in chemical structure

Intravenous anesthetics

39

Stage I anesthesia

Analgesia

40

Stage II anesthesia

Excitement

41

Stage III anesthesia

Surgical anesthesia

- unconscious

- regular respiration

- decreased eye movement

42

Stage IV anethesia

Medullary depression

- respiratory arrest

- cardiac depression & arrest

- no eye movement

AVOID THIS STAGE - REVERSE STAGES IN RECOVERY

43

Ion channel hypothesis

Potentiation of inhibitory channels

- GABA(A) receptors

Glycine receptors

44

No significant action on GABA(A) or glycine receptors

Ketamine

Nitrous oxide

45

Inhibits excitatory channels - NMDA glutatmate receptors

ketamine

46

Activates K channels

inhalational anesthetics

47

Partial pressure

P = (# Mol. of gas A / # Mol. of mixture) x 760 mmHg

48

coefficient correlated directly with potency

inversely correlated with minimal alveolar concentration (MAC)

Oil : gas partition coefficient

49

Coefficient inversely related with anesthesia induction rate

No relation to potency

Blood : gas partition coefficient

50

Meyer-Overton rule

Anesthetics with larger oil/gas are more potent

51

Most common cause of malignant hyperthermia

Halothane

 

Tx: Dantrolene

52

Driving force for equilibrium

alveolar partial pressure gradient

NOT blood concentration

53

Speeds up induction

High partial pressure of anesthetic

High ventilation rate

- agents with high blood/gas are affected most

54

Smaller blood:gas partition coefficient =

faster induction

55

Larger blood:gas partition coefficient = 

slower induction

56

Low cardiac output

high induction rate

57

high cardiac output

low induction rate

58

Reflects tissue uptake of drug

venous blood partial pressure

59

Drug significantly metabolized by the liver

Halothane

60

Inversely proportion to blood:gas

delayed w/ increased duration of anesthesia

profoundly decreased w/ long duration & high blood/gas

recovery rate

61

malignant hyperthermia

halothane

62

maintenence of in-patient anesthesia

pungent odor

isoflurane

63

fluoride ions formed from metabolism may cause renal toxicity

enflurane

64

outpatient surgery

not for induction

usually used with IV agent

desflurane

65

outpatient surgery

anesthesia induction in children

sweet-tasting

"compound A" may be renal toxic

Sevoflurane

66

diffusional hypoxia

nitrous oxide

67

primarily used as adjuct

dental procedures when full anesthesia isnt needed

nitrous oxide

68

N2O diffuses from blood to alveoli,

reduces PO2 in lung

diffusional hypoxia

69

upon discontinuation of N2O

100% O2 to avoid hypoxia

70

contraindications to nitrous oxide use

air-filled cavities (embolus, pneumothorax, etc)

Vit B12 deficiency

71

Most potent inhaled anesthetic

halothane

72

Least potent anesthetic

nitrous oxide

73

most analgesic of inhaled anesthetics

nitrous oxide

74

least analgesic of inhaled anesthetics

halothane

75

barbiturate

contraindicated w/ variegate prophyria

hepatic metabolism

renal excretion

not analgesic

hypotension

Thiopental

76

Rapid onset & recovery even w/ repeat dosing

Anti-emetic action

short day-surgery procedures

Propofol

77

young or head-injured patients

higher-dose infusions

metabolic acidosis, hyperlipidemia, rhabdomyolysis, liver enlargement

 

propofol infusion syndrome (PRIS)

78

minimal cardiovascular effects

etomidate

79

anesthesia induction in patients with cardiovascular diseases

etomidate

80

dissociative anesthesia - awake with profound analgesia and amnesia

ketamine

81

cardiovascular stimulating effects

bronchodilation

ketamine

82

benzodiazepines

midazolam

diazepam

lorazepam

83

opioids

morphine

fentanyl

sufentanil

84

pre-operative anti-anxiety and anterograde amnesia

benzodiazepines

85

anestesia with a combination of several inhaled and/or IV anesthetics, and adjuvant drugs

balanced anesthesia