anesthetics Flashcards
(104 cards)
1
Q
eliminate pain and other sensations in patients who undergo surgical manipulations
A
anesthesia
2
Q
define general anaesthesia
A
Reversible state of CNS depression
3
Q
What effects occur with general anaesthesia? (5)
A
- loss of consciousness: hypnosis
- loss of sensitivity: analgesia, anaesthesia
- loss of reflex activity: autonomic protection
- loss of motility: muscle relaxation.
4
Q
Define local anesthesia
A
intervention is limited to a small area or limb
5
Q
How does local anaesthesia work? (4)
A
- Reversibly nerve block
- ANS blocked (hypotension and vascular tone loss)
- block nociceptive receptors (sensory)
- no loss of consciousness
6
Q
Which anaesthesia makes you lose consciousness?
A
general
7
Q
Which anaesthesia doesnt make you lose consciousness?
A
local
8
Q
The smaller the diameter of nerve fibers (C fibers) the _____ sensitive they are to anaesthetics.
A
more
9
Q
How do we achieve differential blocking with local anesthesia? (2)
A
adjusting concentration and volume
10
Q
Order the nerve fibers from largest to smallest: (3)
A
- A
- B
- C (smallest)
11
Q
Order the nerve fibers from fastest to slowest conduction: (3)
A
- A
- B
- C (slowest)
12
Q
Aα nerve fiber function
A
Motor function and proprioception
13
Q
Aβ nerve fiber function
A
Touch-pressure
14
Q
Aγ nerve fiber function
A
Muscle tone
15
Q
Aδ nerve fiber function
A
Pain-temperature
16
Q
B nerve fiber function
A
Vasoconstriction
17
Q
C nerve fiber function
A
Pain-temperature
18
Q
Blocking order of nerve fibres: (6)
A
- B
- C & Aδ
- Aβ
- Aγ
- Aα
19
Q
Which nerve fibres are for pain-temperature?
A
C & Aδ
20
Q
Sequence of nerve blocking effect wise? (5)
A
analgesia:
- sympathetic block (vasodilation)
- pain block
- thermal and pain fibers
Anaesthesia:
- touch and pressure sensitivity
- motor and proprioceptive
21
Q
Anaesthesia mechanism of action (6)
A
decreased membrane permeability to sodium:
- inhibits Na+ voltage gated channels
- decreases action pot. porpagation
- incr. excitability threshold
- decr. conduction
- full conduction bloackade
22
Q
Physico-chemical characteristics of Local Anaesthetics:
A
- Aromatic benzene ring: lipid solubility (potency)
- Amine portion: hydrophilic (pharmacological action)
- Ester or amide linkage: rate of metabolism and toxicity
23
Q
if anaesthetics have high lipid solubility…
A
more potent
24
Q
if anaesthetics have high protein binding…
A
high duration of action
25
if anaesthetics are less ionized... (2)
- faster entry
| - lower latency period
26
all local anesthetics are _______ with a pKA of ______
- weak bases
| - 7.5-9
27
At physiological pH, local anethesia is....
ionized in high proportion
28
What causes a low pKa LATENCY PERIOD? what does it mean?
low = if pKa and pH are closer, there is more non-ionized drug and it passes through the membrane faster
29
How does the non ionized fraction of local anesthetics work? (3)
passes through lipophilic nerve sheath
- then goes to the axon membrane
- then finally the neuronal membrane
30
How does the ionized fraction of local anesthetics work? (2)
- interacts with the channel to produce pharmacological action
- can only access the binding site from inside the cell, through the channel when it is open
31
The ionized fraction of local anesthetics is....
a charged cation
32
The ionized fraction of local anesthetics is....
a charged cation
33
What happens to the pKa latency period with local anaesthesia when there is a local infection?
acidosis retards diffusion by increasing the ionized fraction
34
CLASSIFICATION OF LOCAL ANAESTHETICS According to the linkage: (2)
- ester
| - amide
35
What are the ester local anaesthetics? (4)
- COCAINE
- PROCAINE
- TETRACAINE
- BENZOCAINE
36
What are the amide local anaesthetics? (7)
```
ß LIDOCAINE
ß MEPIVACAINE
ß PRILOCAINE
ß BUPIVACAINE
ß LEVOBUPIVACAINE
ß ROPIVACAINE
ß ARTICAINE
```
37
What is the SHORT ACTION AND LOW POTENCY local anesthetics?
procaine
38
What are the INTERMEDIATE ACTION AND INTERMEDIATE POTENCY local anesthetics? How long is the action? (4)
- LIDOCAINE
- MEPIVACAINE
- PRILOCAINE
*150 min
39
What are the
| LONG ACTION AND HIGH POTENCY local anesthetics? (4) how long?
- tetracaine
- bupivacaine
- L-bupivacaine
- ropivacaine
*6-8 hours
40
local anesthetic elimination?
renal
41
Which class of local anesthetics have less toxicity?
ester
42
Which class of local anesthetics are allergenic and have cross reactivity?
ester
43
Which class of local anesthetics have a very short half life?
ester
44
Which class of local anesthetics have an average half life?
amide
45
For general anesthesia what drugs cause analgesia?
opiates
46
For general anesthesia what drugs cause loss of relfexes?
neuroleptics
47
For general anesthesia what drugs cause muscle relaxation?
muscular blockers
48
For general anesthesia what drugs cause amnesia and loss of conciousness
anaesthetics
49
To get the effects of general anaesthesia various drugs are going to be administered _____ & ______
simultaneously and sequentially
50
What are the 3 phases of general anaesthesia?
- (preanaesthesia)
- induction
- maintenance
- awakening
51
What drug do we use for general preanaesthesia?
anxyolitics - benzo
52
What drug do we use for induction of general anesthesia? (4)
- anticholinergic: atropine
- IV anaesthetic: (Thiopental-Barbiturate, Propofol, Etomidate, ketamine)
- muscle relaxant: succinylcholine
- opiate: fentanyl, remifentanyl, morphine
53
What drug do we use for maintenance of general anesthesia? (2)
- inhaled anaesthetic: enflurance
| - muscle relaxant: Atracuronium, Venocuronium
54
What drug do we use for awakening after general anesthesia? (3)
- anti-achetylcholinesterase: neostigmine
- anti-opiates: naloxone
- anti-benzo: flumazenil
55
what IV opiates do we use for general anaesthesia? (3)
fentanyl
remifentanyl
morphine
56
what IV barbiturate do we use for general anaesthesia?
thiopental
57
what IV neuroleptic do we use for general anaesthesia?
droperidol
58
what IV anticholinergic do we use for general anaesthesia?
atropine
59
what IV benzos do we use for general anaesthesia? (2)
midazolam
| diazepam
60
what IV anesthesia do we use for general anaesthesia? (3)
- ketamine
- propofol
- etomidate
61
What are the inhaled anesthetic classes and names? (4)
Volatile liquids:
- enuflurane
- halothane
- sio/sevoflurane
Gas:
-nitrous oxide
62
Mechanism of action for general anaesthesia? (4)
- alters synaptic transmission
- hyperpolarization of neuron membrane
- decreased ability of neuron to respond
- acts on ion channels
63
opioid bradycardia with general anesthesia can be controlled with this drug....
atropine
64
Which opioid do we prefer for general anesthesia?why?
fentanyl
| -rapid onset and short duration
65
How long is the effect of ketamine?
short action
66
ketamine indications?
- children
| - minor painful procedures
67
What effects do ketamine have? what effect does it not have (3)
- sedation
- analgesia
- NO respiratory depression
68
What are ketamines cardiovascular effects?
increased:
- sympathetic activity
- blood pressure
- HR
- intracranial pressure
69
Ketamine contraindications (3)
-hypertension
heart disease
stroke
70
Ketamine lipid solubility?
high
71
etomidate indication in anesthesia?
induction
72
etomidate effects?
hypnotic
73
etomidate theraputic index? side effects?
high
| respiratory depression
74
does etomidate cross the BBB?
yes
75
etomidate cross the BBB?
yes
76
length of etomidate action? why?
short because of rapid redistribution
77
etomidate recovery time?
very fast
78
propofol pharmacological effects? (2)
- sedation vs anaesthesia
| - hypnotic
79
propofol physiological effects? (3)
- hypotension
- bradycardia
- respiratory depression
80
propofol pharmacokinetic effects? (2)
Short duration of action, fast recovery
81
What drug has less laryngospasm than fluranes in children?
halothane
82
halothane indications? (2)
- maintence general anaesthesia
| - children
83
halothane pharmacological actions? adverse effects? (4)
sensitizes myocardium to catecholamines:
- high risk of arrhythmias
- respiratory depression
- hepatotoxicity esp. after repeated exposure
84
nitrous oxide adverse reactions?
- megaloblastic anaemia
| - leukopenia
85
to avoid hypoxia we use _____% of nitrous oxide
less than 70%
86
Effect and adverse effects of nitrous oxide?
- analgesic
- loss of consciousness
- myocardial depression
87
What concentration produces loss of consciousness with nitrous oxide?
-80%
88
What concentration of nitrous oxide do we use for analgesia?
- with 50% oxygen
89
What concentration of nitrous oxide do we use for sedation?
with 25% oxygen
| -75%
90
What affect do vasoconstrictions have on local anaesthetics? how? (3)
increased duration of action
- slower absoprtion = prolonged effect
- reduces risk of systemic toxicity
91
vasoconstrictors used with local anaesthetics cannot be applied _______. why? (2)
in distal areas
| risk of necrosis
92
What are the vasoconstrictors used with local anaesthetics ? (2)
- Epinephrine = adrenaline (the most used)
| - Phenylephrine
93
Which anesthetics produce intense vasodilation?
- procaine
- bupivacaine
- lidocaine
94
systemic side effects due to local anaesthesia?
- CNS: b/c lipid solubility
- cardiovascular: tachycardia
- allergic reactions (mainly esters)
- vasovagal rxns
- vasoconstriction adverse reactions
95
cardiovascular adverse effects with local anaesthesia?
- therapeutic doses: tachycardia
| - high doses: hypotension, bradycardia, decreased contractility
96
What does vasovagal mean?
droqp in blood pressure
97
Pregnancy and local anaesthesia?
caution when in first and third trimester
98
Risk of toxicity for local anesthesia is high for the... (2)
children and elderly
99
local anesthesia can cause _______ and _____ failure
renal
| hepatic
100
in what type of drug addicts can vasoconstrictors for local anaesethia not be used?
cocaine addicts
101
Drug interactions with local anesthetics?
1. ANTIARRHYTHMICS class I: Quinidine
2. CNS depressants: increased toxicity
Mainly: antihistamines H1, antidepressants, sedative drugs
3. Beta blockers and cimetidine: decrease the hepatic metabolism of amide local anaesthetics
4. Sulphonamides: local anaesthetics interfere with their antibacterial effects.
102
contradictions for local anaesthesia? (3)
- skin infection at injection site
- swollen/eroded areas
- large areas
103
topical local anaesthesia in dentistry? (2)
- LIDOCAINE: cream, aerosol, gel
| - prilocaine
104
infiltrated local anaesthesia in dentistry? (5)
LIDOCAINE 2%
LIDOCAINE 2% (every ml - 0,0125mg adrenaline) MEPIVACAINE 3%
ARTICAINE 4% (every ml - 0,01mg adrenaline) BUPIVACAINE 0,5% (every ml 0,005mg adrenaline)
