Test 1 Flashcards
Length of Nerve affected needed for anesthesia to occur?
8-10mm
3 structural component of LA
Lipophilic part (benzoic acid derivative) Hydrocarbon chain Hydrophilic part (amino derivative of EtOH/AceH
In Low pH, which form of LA predominates
More cationic form RNH+
In High pH, which form of LA predominates
more basic form RN
Does the basic or cationic LA from have greater tissue perfusion?
Basic does
What does the cationic form bind?
It binds Na+ protein receptor sites
What is the greatest barrier to penetration by LAs?
the perineurium
Which fiber bundles are more apt to not be fully blocked?
The core fibers
How does increasing each of the following affect LA duration? Concentration Gradient Lipid Solubility Protein binding Vasoactivity
top three increase the duration
vasoactivity-vasodilators remove the LA from the area more quickly so that shortens the LA effective time
The only LA that is a vasoconstrictor is _______?
Cocaine
How does Luke like it?
a. Rough
b. Hardcore
c. In the butt
d. All by himself
D is correct
Once absorbed into the blood, where are highest concentrations of LA found?
In highly perfused organs: Heart, brain, liver, kidney, lungs, spleen
Tissue that contains largest percentage of LA?
Skeletal muscle b/c it has greatest mass is all
Esters: where are they metabolized?
in the plasma
Esters: what metabolizes them?
Pseudocholinesterase
Esters: What breakdown product is likely cause of allergic reactions associated with esters?
PABA (para-aminobenzoic acid) Side note: excreted unchanged in the urine pg 6 of first handout
Consequences of Atypical Pseudocholinesterase?
(affects 1/2800 ppl) prolonged levels of LA in blood
Primary site amides are metabolized at?
Liver
what 2 diseases/conditions can lead to toxicity if amide LAs are used?
Hypotension and Congestive Heart Failure (CHF)
What organ excretes both amides and esters primarily?
Kidneys
What system shows first clinical signs of overdose?
CNS
Signs of Overdose (4)
Slurred Speech Shivering Muscle Twitching Tremors of face/extremeties *Excitatory symptoms
Does Lidocaine cause inhibitory or excitatory symptoms?
Inhibitory, it is the exception. Mild sedation/drowsiness can be experienced
Do CNS or cardiovascular symptoms appear first in an LA overdose?
CNS, CV will appear later if LA concentration continues
Benefits of Vasoconstrictors? (4)
Decreased blood flow to injection site
Slower CV absorption
LA remains localized
Decreased bleeding at surgery site
Fxn of Beta1?
Cardiac Stimulation
Functions of Alpha 1/2?
Vasoconstriction of smooth muscles in vessels
Fxn of Beta 2?
Bronchodilation in bronchi
Vasodilation of vascular beds
what does 1:1,000 mean?
1 gram in 1000 mL or 1mg/mL
Where is epinephrine produced in animals?
Adrenal Medulla
What receptors does Epinephrine act upon? Which is dominant?
Both Alpha and Beta (dominant is beta though)
Low dose of Epinephrine affects blood pressure how?
Raises Systolic
Decreases Diastolic
High dose of Epinephrine affects blood pressure how?
Raises Systolic AND diastolic
As Epinephrine lvls decrease from an area, what activity dominates?
Beta2 begins to dominate over Beta1 and vasodilation occurs
Can rebound bleeding be expected with epinephrine?
Yes, it can occur up to 6 hours following surgery
(T/F) Epinephrine increases oxygen consumption in all tissues?
True
4 LA cartridges of 1:100,000 elicit what response in the liver and skeletal muscles?
Glycogenolysis via Beta action
Two step process to terminate epinephrine?
- Uptake by adrenergic nerves
2. Inactivated by COMT or MAO in liver/blood
Common side effects of epinephrine overdose?
Apprehension
Tachycardia
Sweating
Palpation
Epinephrine has 3 concentrations available for dentists, list them.
1: 50,000
1: 100,000
1: 200,000
Epinephrines 3 dilutions and their abilities for anesthetic duration?
All are equivalent
Epinephrines 3 dilutions and their hemostatis abilities?
1:50,000 has a strong reaction that does the other weaker dilutions
Maximum epinephrine dose in a healthy patient? How many cartridges?
0.2mg
11 cartidges or 20mL of 1:100,000
Max epinephrine dose in cardiovascular diseased patient?
0.04mg
2 cartridges or 4mL of 1:100,000
Norepinephrine produced where?
Adrenal Medulla
Mode of action of norepi?
90% alpha and some beta1
Norepi’s affect on heart rate?
Bradycardia
Norepi’s affect on blood pressure?
increase in both b/c of peripheral vasoconstriction
Levonordefrin, aka
Neo-cobefrein
Levonordefrin, mode of action (which receptors)
75% alpha
25% beta
Dose concentration of levonordefrin? and max dosage?
1:20,000
max dose is 1mg for all patients (20 mL or 11 cartridges)
Levonordefrin is the active ingredient in what LA?
Mepivacaine
Acidifying vasoconstrictors does what to shelf life?
Increases it to 18 months
Why is sodium bisulfate added to vasocontrictors?
It is an antioxidant, but this lowers pH so it burns more during injection
If patients are taking Beta-Blockers, why is this a concern if giving epinephrine? *2 exceptions though
Beta’s are blocked so no vasodilation can occur. Therefore, only alpha vasoconstriction occurs and blood pressures increases.
*Metoprolol and Atenolol
Patient has sulfite allergy, can we use an LA with vasoconstrictor?
NOPE, shit out of luck, work fast beotch.
Cocaine interferes with reuptake of what?
Norephinephrine, induces catecholamine sensitivity
If patient doesn’t lie, and states they have taken cocaine within the past 24 hours, can dental procedures still be done?
Not recommended, postpone dental treatment.
What two groups of people are at a greater risk to overdosing?
Small Children
Debilitated Elderly
If two different LA’s are used, how is max dosage figured out?
Use the lower of the two.
Lidocaine, trade name?
Xylocaine
Lidocaine, class?
Amide
Lidocaine, metabolized
Liver
% of lidocaine excreted from kidneys that is unchanged?
10% (hmmm, wonder what would happen if someone where to drink said urine…)
Lidocaine, onset of action time?
2-3 minutes
Lidocaine: Duration w/o vasoconstrictor?
5-10 minutes (no clinical uses)
Lidocaine: duration w/ vasoconstrictor? Pulp and soft tissure
Pulp: 60 minutes
ST: 3-5 hours
Lidocaine max dosage (I feel like he said he would give us the conversion factor)
Max dose is 500mg
Look at pg 14 for maximum dosage example
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Lidocaine, topical usage or not?
yes, it puts the topical on the skin or it gets the hose again.
Lidocaine overdose signs?
Drowsiness, then loss of consciousness and respiratory arrest
Mepivicain, trade name we have to know
Carbocaine
Mepivicaine, class?
amide
Mepivicaine, metabolized where?
liver
Mepivicaine, % unchanged upon excretion
1-16%…okay Dr. Harn, way to be precise there
Mepivicaine, vasoactivity?
slight vasodilation
Mepivicaine onset time?
1.5-2 minutes
Mepivicaine concentrations? (2)
2% with vasoconstrictor
3%without vc
Mepivicaine anesthesia duration:
2%, pulp/soft tissue
3% pulp/st
2%- pulp-60 minutes
st- 3-5 hours
3%-pulp-20minute infiltration or 40 min nerve block
st-2-3 hours
Max dosage of Mepivicaine?
400mg?
Mepivicaine topical usage?
nope
Prilocaine, trade name?
Citanset
Prilocaine, CLass?
amide
Prilocaine, metabolized where? breakdown products?
liver
kidneys/lungs a little bit
*Orthotoluidine
- Orthotoluidine can induce what?
2 How long after Prilocaine injection does it take to appear?
3 How long does it persist? - How is it reversed?
- methemoglobin formation (look for cyanosis with respiratory distress)
- 3-4 hours after injection
- 12 hrs
- IV methylene blue
Prilocaine onset of action?
2-4 min
Prilocaine toxicity compared to Lidocaine
less toxic
Prilocaine concentration?
4%
Prilocaine duration?
- w/o vasoconstritctor
- with vc
- Pulp- infiltration for 10 minutes, block for 60 minutes
- pulpal- 60-80minutes
st- 3-8 hours
Prilocaine max dosage?
600mg
Prilocaine topical usage?
nope
Articaine trade name
Septocaine
Articaine, class, why is this class unique?
Amide, unique derivative from thiophene which makes it more lipid soluble and has an extra ester linkage
Articaine, metabolized where?
90% plasma, 10% liver
Articaine can be reinjected how often? why?
every 30 minutes. it has a short half-life of 20 minutes
Articaine onset?
1-2minutes
Articaine duration?
Pulp- 45-60 minutes
Soft tissure- 2-5 hours
Bupivicain trade name
Marcaine
Bupivicaine class
amide
Bupivicaine metabolized where?
liver
Bupivicaine onset time?
6-10 minutes
Bupivicaine concentration?
0.5%
Bupivicaine duration?
Pulp-90-180 minutes
Soft Tissue- 4-12 hours
Bupivicaine max dose?
90mg
Bupivicaine toxicity compared to Lidocaine?
4 times less
Main problem with bupivicaine?
Little kids are idiots and will self-mutilate themselves and then you’ll get a lawsuit by the parents and apparently “you can’t fix stupid” isn’t a viable defense…ugh…sigh…
Benzocaine class?
Ester
Benzocaine given how?
Only as a topical, NOT AN INJECTABLE DRUG
Lidocaine concentration as a topical?
5% in the base from (recommended)
2% water soluble form also exists
Oraverse, what does it do?
It blocks alpha adrenergic receptors so LA can be removed quickly since no vasoconstriction going on (55-62% reduction)
Onpharma, purpose?
Sodium Bicarbonate added to this LA so pH is 7.35 instead of 3-5 and injection hurts less.
Oraverse, chemical name
Phentolamine Mesylate (this was a test question on the pharmacy pharmacology test for 2nd years last week)
If Harpoons disengages, what happens?
Can’t aspirate.
Needles 25 vs 27 vs 30 comparisons?
25 is the biggest and most accurate and easiest to aspirate with (patients can’t even notice difference b/w the 3 sizes)
Length of Long needle?
32mm
Length of short needle
20mm
How often should needles be changed?
every 3-4 insertions or sooner if bone was hit hard
What could be the issue if pain is felt when pulling the needle out of the mouth?
Fish hook barbs on the tip from striking the bone.
Is the diaphragm permeable or not?
It is semi-permeable
Can cartridges be autoclaved?
Nope
Can cartridges be soaked/stored in a solution?
Nope
What does sunlight do to cartridges?
It increases oxidation which will lower pH. Lower pH causes more pain on injection and decreases permeability of the LA (cationic form present more)
What can cause a large bubble in cartridge?
Freezing cartridge
Is no bubble good or bad?
bad, it means a disinfectant was absorbed into the cartridge and will sting worse if injected
Why shouldn’t tincture be used as a topical anesthetic?
It contains alcohol. It will burn more.
Step to prep a syring (5)
Retract piston insert cartridge engage harpoon and gently push it attach needle expel some solution
How to insert a second cartridge?
same steps, but must strike piston with a sharp blow to embed the harpoon
2 techniques for injecting that should be avoided?
- Using no handrest
2. Using the patient shoulders/arms (they will jerk these first upon pain)
During the insertion of the needle, what direction should palm be facing?
Palms up, easier to inject
Aspirating technique?
Aspirate and then rotate 45 degrees and aspirate some more
Length of time to inject single cartridge?
60 seconds
3 types of local anesthetic injections
Local Infiltration
Field Block
Nerve Block
Local Infiltration?
Solution into area to be treated
Field Block?
Solution near larger terminal nerve giving circumscribed area
Nerve Block?
Solution deposited at main nerve trunk at a distance from area of treatment
Supraperiosteal injection classification?
Field block by definition
Supraperiosteal inj success rate?
95%
PSA inj classification?
Nerve Block
PSA success rage
90%
PSA area numbed?
maxillary molars (MB root of 1st molar on MSA 28%)
PSA average penetration?
16mm
PSA technique
- 25 gauge short needle
- above maxillary 2nd molar at muccobuccal fold
- Up, in, and back at 45 degrees
PSA, if bone contacted early, how to adjust?
It means too great of an angle towards midline, angle needle more towards teeth and keep going
PSA common complications? (2)
Hematoma from pterygoid plexus v3 anesthesia (too lateral)
MSA area numbed?
Max 1/2 premolars and MB root of 1st molar 28%
MSA technique?
- 25 gauge short needle
- above second premolar at mucobuccal fold
- advance needle to apex of tooth
- aspirate
- deposit
ASA aka?
Infraorbital nerve block
ASA area numbed?
Central and Lateral Incisor
Canine/Cuspid
1st n 2nd Premolars 72% of the time
When is ASA done?
When the supraperiosteal injection was ineffective.
ASA technique?
- 25 gauge long
- insert needle at 1st premolar at mucobuccal fold
- Insert 16mm after infraorbital notch found
- Aspirate
- Inject
- Put pressure on infraorbital foramen for 1-2 minutes.
Greater Palatine Technique
- Place cotton swab on greater palatine foramen
- Around the 1st molar region
- Page 5 (lots of tiny detail on bevel placement…i’m lazy..sorry..)
Greater Palatine success rate?
95%
Nasopalatine area numbed?
Anterior portion of hard palate
Nasopalatine injection methods?
single needle penetration
multiple needle penetration