local # 2

Question 1

structure of local anesthetic

Answer 1

aromatic end, intermediate chain, amine end

Question 2

amide

Answer 2

0=c-n-r

Question 3

ester

Answer 3

0=c-or

Question 4

infiltration long and short acting

Answer 4

bupivicaine long acting, tetracaine short acting

Question 5

peripheral block long and short acting

Answer 5

short-lidocaine, long- bupivicaine

Question 6

SAB long and short acting

Answer 6

short- idocaine/procaine, long- bupivicaine or tetracaine with epi

Question 7

epidural long and short acting

Answer 7

long- bupivicaine or ropivicaine with epi, short chloroprocaine

Question 8

mechanism of action of locals

Answer 8

inhibit na+ influx through na specific ion channels in neuronal cell membrane.

Question 9

what must locals be to cross cell membrane and exert action?

Answer 9

non-ionized and lipophilic,then ionized binds to sodium channel

Question 10

pka procaine and onset

Answer 10

8.9 onset- slow

Question 11

tetracaine pka

Answer 11

8.6 slow onset

Question 12

bupivicaine and ropivicaine pka

Answer 12

8.1, moderate onset

Question 13

pka chloroprocaine

Answer 13

9.1, but fast onset

Question 14

lidocaine/etidocaine pka

Answer 14

7.7, fast onset

Question 15

mepivicaine pka

Answer 15

7.6 fast onset

Question 16

decreased pka =

Answer 16

fast onset

Question 17

problem with local toxicity is when

Answer 17

local gets into plasma

Question 18

higher absorption

Answer 18

intercostal>caudal>epidural>brachial plexus>sciatic nerve

Question 19

elimination of locals

Answer 19

prilocaine>etidocaine>lidocaine>mepivacaine>bupivacaine

Question 20

what can be excreted ionized or unionized

Answer 20

unionized are not excreted

Question 21

liver disease and metabolism locals

Answer 21

decreased blood flow, increased metabolism time

Question 22

increased extracellular calcium does what to LA

Answer 22

antagonizes

Question 23

what does increased extracellular potassium lead to

Answer 23

increased action locals

Question 24

protein binding and bupivicaine, lidocaine and procaine

Answer 24

bupivicaine- 95%
lidocaine- 65%
procaine- 6%
protein binding deals with duration. greater protein binding, greater duration

Question 25

cns signs early to late

Answer 25

``` circumoral numbness tongue paresthesia tinnitus blur vision/dizziness agitation slurred speech/unconcious seizures respiratory arrest/death ```

Question 26

cardiovascular effects locals

Answer 26

depression of myocardial automaticity, abnormal pacer activity, decreased excitability, decreased contraction and conduction and arterial dilation

Question 27

if sodium channels are completely closed what happens

Answer 27

absolutely nothing

Question 28

which local is most toxic

Answer 28

bupivicaine

Question 29

what is treatment for bupivicaine toxicity

Answer 29

lipids

Question 30

respiratory effects of local

Answer 30

respiratory depression, decrease hypoxic drive, relaxation of smooth muscle, blok bronchospasm during intubation

Question 31

allergies with amides

Answer 31

very rare- due to methylparaben (preservative)

Question 32

allergies to esters

Answer 32

more common, due to PABA

Question 33

what do you do if there is an allergic reaction

Answer 33

``` d/c drug, 100% o2, epi 0.01-0.5 iv/im fluids 1-2L benadryl hydrocortisone intubation ```

Question 34

what can prilocaine levels greater then 10mg cause?

Answer 34

methemoglobinemia

Question 35

cauda equina from

Answer 35

lidocaine spinal- neuronal damage

Question 36

what channel is responsible for depolarization of neuronal cells?

Answer 36

voltage gated sodium channels

Question 37

local anesthetics work

Answer 37

on inside of cell, no action on outer

Question 38

weak bases will have more drug available

Answer 38

at ph higher then physiological, bases love bases

Question 39

1% lidocaine

Answer 39

10mg/ml

Question 40

2% lidocaine

Answer 40

20mg/ml

Question 41

1:100,000 epi

Answer 41

10mcg/ml

Question 42

1:200,000 epi

Answer 42

5mcg/ml

Question 43

.1% lidocaine

Answer 43

1mg/ml

Question 44

local anesthetic with pka closer to physiologic ph will have

Answer 44

greater concentration of nonionized base that can pass through nerve cell membrane and rapid onset

Question 45

what must la be to cross membrane

Answer 45

uncharged to penetrate membrane, then ionized to chared binds

Question 46

pka

Answer 46

50% unionized, 50% unionized at that ph

Question 47

if ph is lower then pk

Answer 47

more ionized then unionized

Question 48

if ph is higher then pka

Answer 48

more unionized

Question 49

decreased ph equals

Answer 49

greater h+ concentration