Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology for Anesthesia > 07 - Local Anesthetics > Flashcards

07 - Local Anesthetics Flashcards

1
Q

Local anesthetics work by causing the loss of

A

sensory
motor
autonomic function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The resting potential of a cell membrane is due to _______. Voltage gated Na and K channels depolarize the membrane, leading to

A

Na-K-ATPase

action potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

LA enter the cell and bind to

A

Voltage-gated Na channels to prevent Na influx and slows conduction
May bind to other channels as well (K, Ca, NMDA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How many types of nerve fibers are there? List them in order from smallest to largest.

A

3

C < B < A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a differential block?

A

= Autonomic (C and B) -> Sensory (C and A) -> Motor (A)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Nerve fibers are surrounded by ____ and bundled into ______ which are surrounded by

A

endoneurium
fascicles
perineurium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Groups of fascicles surrounded by epineureum?

A

Axons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Nerves can be surrounded by a

A

myelin sheath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

LAs don’t fight their way through the myelin, they bind at ____ between the myelinated segments

A

Nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Myelinated fibers (B) are ____ to LA than nonmyelinated fibers (A, C)

A

more sensitive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The generalized notion that LA block the smallest fibers first or most is

A

CLEARLY WRONG

According to Miller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Small fibers (C) are ____ to LA than large fibers (A)

A

more susceptible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the sequence of a differential block?

A

B -> C -> A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the sequence of loss for sensory fibers?

A

Temp -> pain -> touch -> deep pressure -> proprioception

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Local anesthetics are ____. How do they become charged?

A

Weak bases

Accepting a proton on the amine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The protonated species of a LA is

A

More potent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

pKa of amides

A

7.6-8.1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

pKa of esters

A

8.2-9.0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The ability of an LA to penetrate membranes depends on its

A

lipid solubility, charge, size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Adding HCO3 with an LA ____ onset, but can cause

A

speeds

precipitation (bupivicaine)

21
Q

The density of a block depends on

A

concentration - need enough drug to saturate binding sites and prevent transmission of AP
volume - need to block a critical length of nerve fiber

22
Q

The duration of action of a block correlates with

A

lipid solubility

23
Q

LAs are rapidly absorbed through _____ but poorly through

A 
Mucous membranes (conjunctiva, trachea, oropharynx)
Intact skin
24
Q

What is EMLA cream?

A

Stands for Eutectic Mixture of Local Anesthetics - eutectic mixture of equal quantities by weight of lidocaine and prilocaine.

25
Q

What is the onset of EMLA cream and its depth of penetration?

A

1 hour

3-5 mm

26
Q

EMLA cream can cause?

A

Methemoglobinemia

27
Q

Systemic absorption of LA is proportional to ______ and

A

Vascularity, vasoconstriction

IV > tracheal > intercostal > caudal/epidural > peripheral nerves > subcutaneous

28
Q

Avoid epi on

A

fingers, toes, penis, nose

29
Q

The only local anesthetic that causes vasoconstriction is

A

COCAINE!!!

30
Q

Vasoconstriction with LA causes increased ____ and decreased _____. This is less pronounced with

A

Neuronal uptake
Redistribution

Bupivicaine

31
Q

Which LA are esters and which are amides?

A

Esters have one i and amides have two i

32
Q

How are esters metabolized?

A

Ester hydrolysis by pseudocholinesterase

Excreted in urine

33
Q

There is no pseudocholinesterase in

A

CSF

34
Q

Procaine/benzocaine can cause formation of PABA (4-aminobenzoic acid) which can cause

A

allergic reaction

35
Q

Which ester is partially metabolized in the liver?

A

COCAINE

36
Q

Amides are metabolized in the

A

liver

37
Q

T or F. Metabolization of esters is faster than amides.

A

True, ester hydrolysis is rapid

38
Q

Toxicity of LA is treated by

A

Benzos (caution with thiopental, propofol)

39
Q

Toxicity spectrum of LA

A

Circumoral/tongue numbess, dizziness, tinnitus, blurred vision
Restlessness, agitation, nervousness, slurred speech, drowsiness, LOC
Muscle twitching, seizures

40
Q

Lidocaince can ____ CBF and minimize increase of ____ with intubation

A

decrease

ICP

41
Q

A lidocaine infusion can decrease MAC by

A

40%

42
Q

What are the effects of COCAINE?

A

euphoria, restlessness, tremors, convulsions, respiratory failure

43
Q

Repeated doses of lidocaine and tetracaine can cause

A

Cauda equina syndrome

44
Q

What can be used to treat ventricular arrhythmias?

A

IV lidocaine

45
Q

LA can sometimes cause cardiac arrest. The cardiotoxicity is reversed by

A

Intralipid

46
Q

This LA rapidly blocks Na channels and can be difficult to resuscitate

A

IV bupivicaine

47
Q

Are esters or amides more likely to cause allergic reaction? Why?

A

Esters
They are derived from PABA

PABA = procaine and benzocaine allergy

48
Q

How does cocaine work?

A

Prevent NE reuptake

49
Q

Methemoglobinemia is commonly caused by ______. What do you use to treat it?

A

Prilocaine and benzocaine, sometimes lidocaine
Methylene blue

Met Hgb >10%
Met Hgb > 50% is severe

Pharmacology for Anesthesia (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions