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advanced pharm 2 for na > Nagelhout Video Local Anesthetics 1 - Exam 2 > Flashcards

Nagelhout Video Local Anesthetics 1 - Exam 2 Flashcards

1
Q

What are 2 main types of local anesthetics?

A

esters and amides
-esters have 1 “i” and amides have 2 (lidocaine = amide, procaine =ester)

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2
Q

3 parts of LA structure

A

Lipophilic Benzene Ring (aromatic group)

Hydrophilic Quaternary Amine (base)

Intermediate chain in between them (made of ester or amide)

-if chain has a N in it = amide
-if chain has 2 oxygen groups = ester

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3
Q

Which LA class has a higher allergy potential?

A

Ester
-metabolites are in common household items so pts can have ester allergies without having been exposed before

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4
Q

T/F If pt has an allergy to an ester, they can just have a different ester

A

false

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5
Q

T/F If pt has an allergy to an amide, they can just have a different amide

A

true
-can also have an ester too

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6
Q

How are amide LAs metabolized?

A

in liver by CYP1A2 and CYP3A4
-if pt is ultrarapid metabolizer will have a significant blood level

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7
Q

How are ester LAs metabolized?

A

catalyzed by plasma and tissue cholinesterase via hydrolysis
-does this rapidly

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8
Q

Are esters synthetic or natural?

A

mostly synthetic
-except cocaine

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9
Q

Which LA are longer acting and why?

A

amides
-more lipophilic and protein-bound, require transport to liver to metabolize

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10
Q

Longest acting LA ester?

A

Tetracaine

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11
Q

Examples of ester LAs

A

Cocaine
Procaine (Novacaine)
Chloroprocaine (Nesacaine)
Tetracaine (Pontocaine)
Benzocaine (Anbesol, Cepacol)

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12
Q

Examples of amide LAs

A

Lidocaine (Xylocaine)
Prilocaine (Citanest)
Ropivacaine (Naropin)
Bupivicaine (Marcaine, Sensorcaine)
Mepivicaine (Cabocaine)

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13
Q

The fatter the nerve, the _ it is to block.

A

harder
-Alpha a (motor and proprioception) is larger and is blocked last, comes back first
-heavy myelination makes it harder to block too

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14
Q

Order of nerve blocks by type (first to last):

A

-B (pre ganglionic- autonomic**)
-A Delta + C fibers (C>A deltapost ganglionic-pain/temp/touch)
-rest of A fibers (gamma>beta>alpha-proprioception +motor)

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15
Q

Neuraxial fiber recovery order occurs in _.

A

reverse
-motor/proprioception function comes back 1st
-A alpha>beta>gamma
-A delta > C
-B

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16
Q

***Neuraxial sensorimotor function block order:

A

sympathetic function
pain
temp, touch, pressure
proprioception
motor function

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17
Q

If LA is in tertiary form it is _ (non/ionized) and if it is in its quaternary form it is (non/ionized)

A

nonionized
ionized

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18
Q

T/F When injected into skin, LA becomes ionized.

A

False
-it is both

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19
Q

T/F When in the skin, ionized LA crosses into the nerve cells

A

False,
NON IONIZED

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20
Q

T/F When in the nerve cell, LA splits up again into ionized and nonionized versions and the ionized version travels to the sodium channel and blocks it from inside.

A

TRUE!!!

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21
Q

Which part of the LA molecule is ionized or hydrophilic?

A

Q Amine

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22
Q

Which part of the LA molecule is nonionized or hydrophobic?

A

Tertiary Amine

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23
Q

All LA are both lipophilic and hydrophilic and are weak _ (acids/bases)

A

bases
-all LA are bases bc they have a N group

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24
Q

How do LA work?

A

Block Na+ channels

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25
Q

The lower a LA’s pKa, the _(faster/slower) its onset will be bc the closer the pKa is to 7.4, the _ (smaller/ larger) its portion of NONionized drug is

A

faster
larger

-nonionized part penetrates the nerve
-EXCEPTION: Chloroprocaine, this is bc its given in such high concs which make it fast

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26
Q

T/F The higher the pKa on a LA, the faster it works

A

false

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27
Q

The more protein bound LA is, the _ (shorter/longer) its duration is

A

longer
-protein binding helps it stick around tissue and nerves longer

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28
Q

Long duration LAs:

A

-Cocaine
-Tetracaine
-Ropivacaine
-Etidocaine
-Bupivacaine

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29
Q

When adding vasoconstrictors to LA, the drug is usually Epi at a concentration of 1: _ or _mcg/mL

A

1:200,000
5mcg/mL

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30
Q

Adding vasoconstrictors to LA increases the _ and _ of them while decreasing their risk of _

A

depth and duration
toxicity

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31
Q

Extent in which epi prolongs the duration of regional and epidural anesthesia is dependent on which 2 factors?

A

-type of LA
-site of injection

-spinal anesthesia is actually a slower onset with epi

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32
Q

Why is the peak concentration of an LA decreased when you add Epi?

A

vasoconstriction slows the absorption of LA into system, prolonging its effect in tissue/nerves

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33
Q

Lidocaine 1% and 2% MAX with and without epi:

A

Lido: 4mg/kg
Lido + Epi: 7mg/kg

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34
Q

Bupivacaine 0.75% MAX dose with and without epi:

A

Bupi: 2.5mg/kg
Bupi + Epi: ~3mg/kg

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35
Q

Max dose of cocaine is _ mg and it can only be given _.

A

200mg MAX - not per kg
topically

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36
Q

Cocaine blocks the reuptake of _ and _ causing sympathomimetic effects

A

epi and norepi

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37
Q

In LA overdose, resp depression occurs, causing _ and _.

A

resp. depression
hypoxia
acidosis

38
Q

In LA over dose causing acidosis from respiratory depression, the acidosis could cause _ (increased/decreased) ionized LA in the brain which _ (increases/decreases) its ability to leave.

A

increased
decreases

-overdose is potentiated by the acidosis it causes by preventing it from leaving BBB bc its more ionized; higher CNS toxicity

39
Q

How to fix LA toxicity?

A

fix the acidosis is causes first, then treat toxicity

-can’t leave BBB with acidosis bc LA is more ionized

40
Q

Why would a fetus retain more LA than its mother?

A

fetal pH is lower, and more acidotic, so LA ionizes and leaves fetal system slower

-especially if mom is acidotic too.

41
Q

What will happen if LA is injected accidentally into septic tissue?

A

it will not reach the site of action due to the ACIDOTIC infected environment, it will ionize in the skin and linger

42
Q

Adding CO2 to LA has what effect?

A

Will diffuse readily into nerve, once in the nerve it will more readily accept H+ and ionize more, so there is a higher conc of LA at the site of action
-faster onset

43
Q

Adding bicarb to LA has what effect?

A

Improves diffusion of LA by making it more basic, increasing its NONionized portion which goes into nerve quicker = quicker onset!

-base+ base = NON ionized

44
Q

Lipid solubility of an LA is correlated with which factor?
A. Potency
B. Onset
C. Metabolism
D. Duration

A

A. Potency

-higher lipid solubility = better diffusion = needs less mg dose to work well

45
Q

Dissociation constant (pKa) of an LA is correlated with which factor?
A. Potency
B. Onset
C. Metabolism
D. Duration

A

B. Onset

-lower pKa = higher portion of tertiary (diffusible/nonionized) state = faster onset

46
Q

Chemical linkage (ester/amide) of an LA is correlated with which factor?
A. Potency
B. Onset
C. Metabolism
D. Duration

A

C. Metabolism

-esters = HYDROLYZED in plasma
-amides = BIOTRANSFORMED in liver

47
Q

Protein binding of an LA is correlated with which factor?
A. Potency
B. Onset
C. Metabolism
D. Duration

A

D. Duration

-higher affinity for protein at receptor site = prolonged presence of LA at site of action

48
Q

The MORE lipid solubility an LA has, the _ (more/less) it diffuses and the _ (higher/lower) dose is required to be effective

A

more
lower

49
Q

The LOWER the pKa LA has, a _ (smaller/larger) amount of tertiary (nonionized) molecules exist which can diffuse and _ (speed/ slow) the onset.

A

larger
speed

50
Q

Of the 2 kinds of LAs,
_ are hydrolyzed in the plasma and _ are biotransformed in the liver

A

esters
amides

51
Q

The HIGHER affinity an LA has for protein, the _ (shorter/ longer) the presence lasts at the site of action

A

longer

52
Q

LAST Lido classic progression
Therapeutic level/ Stage 1
-plasma conc (mcg/mL)

A

5mcg/mL

-lightheadedness, tinnitius, circumoral or tongue numbness

53
Q

LAST Lido classic progression
Stage 2
-plasma conc (mcg/mL)
-s/s

A

5-10mcg/mL

-muscle twitching, visual changes

54
Q

LAST Lido classic progression
Stage 3
-plasma conc (mcg/mL)
-s/s

A

10-20mcg/mL

-convulsions, coma, unconsciousnes

55
Q

LAST Lido classic progression
Stage 4
-plasma conc (mcg/mL)
-s/s

A

20-25+mcg/mL

-resp arrest, CVS depression

56
Q

T/F Bupivacaine can be used for IV regionals

A

FALSE HELL NAH
-doesn’t follow classic LAST progression like Lido (CNS s/s -> cardiac s/s)
-cardiac-specific binding causes extreme cardiac s/s (arrest) as 1st signs of LAST

57
Q

How is Ropivacaine different than Bupivacaine?

A

same MOA but does NOT possess same cardiac toxicity, so doesn’t have the same horrible cardiac LAST s/s

58
Q

T/F A pt experiencing LAST will always show CNS s/s first.

A

False
-not always

59
Q

The most common CNS s/s during LAST is _

A

seizures

-lots of arrhythmias as well, brady/asystole most common

60
Q

Most cases of LAST happen within _ min/s.

A

LESS THAN 1 min

-could be while injecting!

61
Q

LAST
-factors influencing plasma conc.

A

-dose
-rate absorbed
-site injected/ use of adjuncts
-biotransformation or elimination of drug

62
Q

LAST
-pvn

A

-US GUIDANCE
-benzos as premedication can lower seizure rate but mask s/s
-be ready for anything
-LA and resusc drugs close by
-double check dose(give LOWEST effective dose)
-deliver in increments (3-5ml w/ 15-30s pause between)
-aspirate Q injection!
-TEST DOSE! (45mg Lido 15mcg Epi!)
-VERBAL communication w pt

63
Q

LAST
-Tx, resp

A

O2-mask, LMA, ETT

64
Q

LAST
-Tx CV/meds

A

-lift legs, fluids, BP meds
-anticonvulsants (benzos, prop, thiopental)
-standard arrhythmia drugs (EXCEPT CCB, sodium valproate, phenytoin, vasopressin, and other LAs)

65
Q

LAST
-lipid infusion

A

if pt unresponsive to standard resusc. but can give immediately after securing airway*
-bolus
-infusion
-CHEST COMPRESSIONS TO CIRCULATE
-repeat bolus Q 3-5 up to 3mg/kg
-leave infusion on until CV stable

66
Q

LAST
-Intralipid 20% bolus dose

A

Pt <70kg :
1.5mL/kg IBW over 2-3minv
repeat bolus x3 for persistent CV collapse; upper limit 12mL/kg in 1st 30 min

Pt >70kg
20% Interlipid
100mL over 2-3 min

67
Q

LAST
-Intralipid infusion

A

Pt<70kg:
0.25-0.5mL/kg /min

Pt >70kg:
200-250mL over 10-20 min
-keep on for at leas t10 min after CV stable

68
Q

LA toxicity requires close control on what factor due to the factor’s influence on inotropic/chronotropic effects?

A

O2 + ventilation
-hypoxia, acidosis, and hypercarbia worsen this

69
Q

LAST
-TEST DOSE concentrations and actual dose

A

3mL of 1.5% Lidocaine + 1:200,000 Epi
= 45mg Lido + 15mcg Epi

70
Q

T/F My pt’s IV is just aight… they should be fine for a spinal block, right?

A

FALSE
-if they develop LAST you’re SOL
-have a GOOD IV and resusc tools ready

71
Q

T/F Negative needle aspiration means you definitely aren’t going intravascular with a LA

A

false!
there is a ~2% false negative aspiration rate

72
Q

When using a fixed needle approach for LA, the time between injections should encompass 1 circulation time which is ~ - sec

A

30-45sec

-give longer intervals for larger doses of LA

73
Q

Intravascular injection of a test dose of Epi (10-15mcg/mL) causes ~ _ beat increase in HR and ~ _ mmHg increase in BP

A

10+ beat

15+mmHg

-beta blocker, active labor, old age, and GA can mask this!

74
Q

Subtoxic test doses of intravascularly injected LA can cause s/s of mild systemic toxicity like:

A

excitation, auditory changes, metallic taste

-if fentanyl is part of test dose for laboring pts = sedation

all of this is true only if pt is NOT premedicated

75
Q

LAST
-early s/s

A

CAN BE MASKED IF PREMEDICATED W BENZO
-dizzy
-tongue numb*
-difficulty focusing
-tinnitis**
-confusion
-muscle twitching

76
Q

LAST
-late s/s

A

-ton/clon sx
-coma
-resp + cardiac arrest

77
Q

T/F A pt experiencing LAST can present initially with CNS and cardiac s/s at the same time

A

true
-could also just completely bypass CNS effects as well

78
Q

Delayed (1-5min) presentation of LAST s/s indicates suggests _ or _ intravascular injection

A

partial or intermittent

79
Q

Immediate (<60sec) presentation of LAST suggests intravascular injection of LA with direct access to the _

A

brain

80
Q

LAST can present > _ min after injection so it’s important for CRNA to monitor them for _ mins afterwards.

A

> 15 min
30 min

81
Q

T/F LAST has a higher association with pts suffering from underlying diseases

A

true
-watch out for your older ASA 3-5 pts more closely

82
Q

You successfully gave a test dose of LA with no problem, however, when you give our pt a spinal injection, they start experiencing a reaction. Their symptoms almost resemble late signs of LAST but you’re not 100% positive. How will you proceed?

A

Absolutely treat this like it’s LAST.

-keep a low threshold to treat for LAST especially if atypical symptoms arise and they received more than a test dose

83
Q

Goal of LAST airway management:

A

prevent hypoxia and acidosis by maintaining their airway/ventilation

84
Q

1st line treatment for a seizure during LAST:

A

benzos!
-give versed, let them relax if possible, let LA wear off and either try again or cancel case if pt unstable

85
Q

Your pt starts seizing after receiving a standard dose of LA spinal injection. They appear to be breath-holding and their SpO2 is dropping. What’s your next move?

A

-stop seizure (benzos, small doses propofol (if not hypotensive), or sux)
-give O2/ LMA/ intubate

86
Q

Why should large doses of propofol be avoided in a pt seizing who is experiencing LAST ?

A

cardio depressive, will bottom out BP when pt reaches their postictal state

87
Q

Which drugs should be avoided during ACLS on a pt experiencing LAST?

A

-standard dose epi (use 10-100mcg boluses)
-VASOPRESSIN
-CCB/ Beta blockers
-LIDOCAINE/PROCAINAMIDE :) lol

-Amio is the DOC for ventricular arrhythmias

88
Q

If pt does not respond to lipid emulsion or vasopressors during ACLS when experiencing LAST, what is the next option for them?

A

cardiopulmonary bypass

-if at a smaller hospital, not a bad idea to call for a neighboring hospital for a transfer as soon as cardiac s/s come up

89
Q

Which type of LA is more likely to cause LAST?

A

Amides

90
Q

LA block voltage-gated _ channels which interrupts the _ and _ of nerve impulses in axons.

A

Na+ channels
initiation and propagation

91
Q

If LA is put in a basic solution, it _ (will/will not) carry a charge, and if it’s put in an acidic solution, it _ (will/will not) carry a charge.

A

will not (nonionized)
will (ionized)

92
Q

CPR is especially hard with which LA drug’s cardiac toxicity?

A

Bupivacaine

advanced pharm 2 for na (14 decks)

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