Local Anaesthetics

Front 1

Local anaesthetic- MOA

Back 1

- reversibly binds Na channels at the INTERNAL part of the membrane, in nerves, to block conduction of AP thus prevents depolarization.
- Blocks both sensation and motor function of affected fibers.
- The membranes will be stabilized.
- active nerves are more senstive to the block
- nerves w/ small diameter more sensitive than large dm
- myelinated nerves are more sensitive than unmyelinated but size factor will predominate
- first will lose pain, temp then touch and last will lose pressure

Front 2

What other agent is given w/ local anaesthetics? In what area can you NEVER give this agent?

Back 2

1. vasoconstrictor-- epinephrine, to enhance local effects and not let the anesthetic spread all over (cocaine does not require epi-- so cocaine can be used in finer, nose, penis and toes)

2. never use in finger, nose, penis, toes-- necrosis can result

Front 3

Local anaesthetics are generally very ____ and thus are difficult to get into abscesses and infected tissue b/c these are generally ____. Thus must give a LOT of local anaesthetic to get to INTERNAL side of Na channel across the nerve membrane.

Back 3

1. basic
2. abcesses are acididc

Front 4

Local anaesthetics- AE

Back 4

- CNS, CD, hematologic
- CNS toxicity occurs before CV toxicity
- METhemoglobinemia-- increase in met Hb which does not bind O2 as well

Front 5

How to tx CNS toxicity?

Back 5

- dizzy, drowsy, convulsion, resp depression
- tx w/ anticonvulsant like diazepam and barbituates, DO NOT USE phenytoin which can potentiate the CNS sx

Front 6

CV depression adn hypotn b/c of ___-- leads to chest pain and palpitations.
How to tx?
Which of the local anaesthetics has MAJOR cardiotoxicity?

Back 6

1. vasodilation
2. tx w/ cardiac stimulants--NE, ephedrine
3. bupivicaine- may happen even before CNS SE

Front 7

Which local anaesthetic causes more metHb?
How to tx metHb?

Back 7

1. prilocaine
2. methylene blue -- but cant give too much

Front 8

Local anaesthetic-CI

Back 8

- allergy
- if pt is allergic to amine can give ester and vice versa

Front 9

Local anaesthetic- Use

Back 9

- minor surgical procedules, spinal anaesthesia-- given topically, local injection, as nerve block, or IV block w/ tourniquet( Bier block), spinal anesthesia in subarach space, and epidural

Front 10

Procaine, cocaine, tetracaine, chlorprocaine, adn benzocaine are ____ which are hydrolyzed by ____. What are product has similar allergen?

Back 10

1. ESTERS
2. plasma cholinesterases
3. sunscreen-- also contains PABA

Front 11

What is the max dose of the ____ procaine?
Procaine- duration of action?

Back 11

1. procaine is an ester
2. 7 mg/kg
3. short

Front 12

What is the max dose of the ____ cocaine?
Cocaine- Duration of action?

Back 12

1. cocaine is an ester
2. 1.5-3 mg/kg--given nasally
3. medium duration of action

Front 13

lIdocaIne, mepIvacaIne, bupIvacaIne, etIdocaIne, ropIvicaIne, and prIlocaIne are all _____. These are metabolized by ___ and are generally metabolized SLOWER than the other types of local anaesthetics. This means that amides can lead to more ___.

Back 13

1. AMIDES-- all have two I's in them
2. liver microsomal enzymes
3. are metabolized more slowly than esters thus can more easily lead to systemic toxicity

Front 14

Lidocaine- max dosage, duration of action

Back 14

1. lidocaine- 4.5 mg/kg w/o epi, 7 w/ epi
2. medium- 30-60 minutes

Front 15

Bupivicaine- max dosage, duration of action

Back 15

1. bupivicaine-1.6-2 w/o epi, 3 w/ epi
2. long- 120-240 minutes

Front 16

Mepivicaine- max dosage, duration of action

Back 16

mepivicaine- 7mg/kg ip to max of 400 mg, 45-90 mins

Front 17

Potency of local anesthetics dependant on ___.
Onset is dependent on ___.
Duration is dependent on strength of ___

Back 17

1. lipid solubility
2. pKa-- if pKa matches w/ site of injection more likly more quick onset
3. protein binding

Front 18

The ability of local anaesthetic to penetrate into the intracellular nerve depends on what form of the anaesthetic?

Back 18

1. the non-ionized base form

Front 19

General anesthetics characteristics-- primary will see loss of ___ then secondarily absence of perception, reduced reflexes, analgesia, muscle relaxation, and _____ on recovery

Back 19

1. consciousness
2. amnesia

Front 20

Partial pressure-- measures tendency to ___ a given phase
- at the same partial pressure the substance with ____ has lower steady state concentration

Back 20

1. escape
2. lower solubility

Front 21

At the same concentration the substance w/ ____ is more likely to escape and therefore has a higher ____.

Back 21

1. lower solubility
2. partial pressure

Front 22

MAC - min alveolar concentration-- this is the min partial pressure in the alveoli that produces ___ to noxious stimulus in avg pt.
MAC is a measure of _____
EXAM Q

Back 22

1. immobility
2. potency

Front 23

If a drug has low blood solubility then it will have rapid____.
If a drug has low lipid solubility then it is ____
EXAM Q

Back 23

1. low blood solubility-- rapid induction time
2. low lipid solubility - low potency

Front 24

Sedatives such as BZD, neuromuscular blocking agents such as succinyl choline, anti muscarinics for airway control and local anesthetics are used as ____

Back 24

1. adjuvants

Front 25

Diffusional hypoxia

Back 25

- when inhaled anesthetic is stopped, that which had been dissolved in blood ppts out in lungs- thus the O2 and CO2 in the lungs gets diluted leading to HYPOXIA

Front 26

Second gas effect-

Back 26

- when a large concentration of a primary gas is given, it makes a vacuum drawing in more of the secondary gas than would have been drawn in if the secondary gas was given alone

Front 27

Redistribution refers to the fact that the most ___ organs will receive the anesthetic first and will also be the first to get rid of it.

Back 27

1. most highly perfused

Front 28

Inhalational anesthetics- MOA, AE

Back 28

MOA: unknown
AE: HYPOTENSION, myocardial depression, increase in resp rate, N/V
- malignant hyperthermia if use inhalational anesthetic and succinyl choline- drastic increase in skeletal muscle oxidative metabolism
- some enhance hearts rxn to catecholamines-- which can cause arrhythmias

Front 29

How to tx malignant hyperthermia?

Back 29

- when succinyl choline and inhalaitonal anesthetic given together may lead to malignant hyperthermia- TREAT by ending anesthesia adn infusing DANTROLENE

Front 30

Sevoflurane- Class, Use

Back 30

- excellent control of depth, rapid recovery, and does not irritate airways
- inhalational anesthetic

Front 31

Isoflurane- Use, Class

Back 31

Class: inhalational anesthetic
Use: widely used, fast induction, good muscle relaxant, does not produce sz like EEG activity (unlike enflurane)

Front 32

Halothane- Use, AE

Back 32

Use: high lipid solubility, high blood solubiltiy- high potency, slow induction
AE: hepatotoxicity, arrhythmia, malignant hyperthermia, -- halothane HEPATITIS- seen w/ re-exposure

Front 33

Methyoxyflurane- Use

Back 33

- most potent, arrhythmias, nephrotoxicity via metabolite

Front 34

Enflurane- Use

Back 34

- proconvulsant, muscle relaxant

Front 35

NO- Use, AE

Back 35

- MAC-- 105%-- CANNOT use alone so must use 2nd gas effect
- low lipid solubility, low blood solubility- low potency, fast induction
- amnesia, analgesia
AE: trapped air pockets can cause pain

Front 36

Propofol- Use, Class
- rando CI

Back 36

Class: IV anesthetic
Use: rapid anesthesia, rapid emergence, littl epost op nausea, no impair on hepatic or renal fx- used for induction and maintenance of anesthesia and sedation-- is usually mixed w/ egg whites so do not give to pt who is allergic to eggs

Front 37

Thiopental- Use, Class

Back 37

Class: IV anesthetic
Use: barbituate that is high potency-- very lipid solubal- rapid induction into brain but SHORT duration due to redistribution
- used for induction of anesthesia
AE: myocardial depression is dose dependant- min resp depression

Front 38

Etomidate- Use, Class, AE

Back 38

Class; IV anesthetic
Use: hypnotic though NO ANALGESIA- used when risk of hypotension
AE: no CV?respiratory depression-- involuntary muscle movements seen

Front 39

Ketamine- Class, Use, AE

Back 39

Class: IV anesthetic
Use: acts as dissociative anesthetic-- pt non communicative but may move and seems awakke- GREAT analgesic
AE: CV stimulation, causes disorientation, HALLUCINATIONS as re-emerging

Front 40

DOC for hypnosis

Back 40

Barbituates or ketamine

Front 41

DOC for analgesia

Back 41

Opioids or ketamine

Front 42

DOC for amnesia

Back 42

BZD

Front 43

Concept of balanced anesthesia?

Back 43

Try to combo anesthetics to achieve mix of hypnosis, analgesia, and amnesia

Front 44

Pre-emptivve analgesia?

Back 44

using analgesic before gicing general anesthesia improves recovery post op