Midterm Flashcards
What are the 3 parts of local anesthetic?
- Aromatic Group
- Intermediate Chain
- Secondary or Tertiary Amine
Confers lipophilic properties:
Aromatic group
Supplies spatial separation between lipophilic and hydrophilic ends and connects them with an ester or amide linkage:
Intermediate chain
Affects pKa (& lips vs. water solubility) and influences speed of onset:
Secondary or tertiary amine
T/F: secondary/tertiary amines are bases:
T
How strongly the organic base portion of the L.A. molecule holds onto its proton (AKA acid dissociation constant):
pKa
High or low pKa: weaker acid (stronger bases) Hold proton more tightly Remain positively charges and cross cell membranes poorly. Slower onset.
High pKa
High or low pKa:
Shed proton more easily.
Become non-ionized “free bases”.
Cross membranes more easily.
Low pKa
Which locals has a high pKa and slower onset?
- Bupivacaine (Marcaine)
Dbl T/F:
LAs stabilize cell membranes.
LAs act mainly be promoting rapid Na+ influx.
T
F: LAs act mainly by inhibiting rapid Na+ influx.
T/F: LAs are unusual in that they lose their effect when absorbed into the blood stream.
T
How does an LA stop working (numbness goes away)?
Redistributed
Duration of action is based on _____ ______ not metabolic transformation (half-life).
Protein bonding
Half- life has a bearing on _____, not duration of action.
Toxicity
Local are all vasodilators except for ____.
Cocaine
Vasoconstrictors are needed to slow _____.
Redistribution
Which area for anesthesia takes the longest to develop and leaves first?
Pulpal anesthesia
Which lasts longer, nerve blocks or infiltration?
Nerve blocks
Which amides are metabolized in the blood?
Only Articaine (septocaine). All others are metabolized in the liver.
Where are esters metabolized?
Cocaine = liver
Procaine (Novocaine) and Benzocaine = blood
Which LAs are excreted only in the kidneys, not as metabolites?
Mepivicaine (Carbocaine)
Bupivicaine (Marcaine)
Which LAs are excreted through the kidneys and as metabolites?
Lidocaine (Xylocaine)
Artisane (Septocaine)
Which 2 LA’s have a rapid onset?
Mepivicaine (Carbocaine)
Lidocaine (Xylocaine)
Rate at which local is removed from the plasma:
1/2 life
List duration of action of locals, shortest to longest:
- Mepivicaine (Carbocaine)
- Lidocaine (Xylocaine)
- Articaine (Septocaine)
- Marcaine (Bupivicaine)
Which LA is not recommended in pedo or cognitively impaired adults?
Marcaine (Bupivicaine)
Accumulation of orthotoludine in the blood can produce this:
Methemoglobin.
Which two LAs can produce methemoglobin?
Prilocaine and Articaine (Septocaine)
T/F: Methemoglobin is methylated hemoglobin:
F: it is hemoglobin where the iron has been oxidized to the ferric (Fe3+) instead of ferrous (Fe2+) state.
T/F: Methemoglobin has poor O2 delivery to tissues:
T
What is the max dose of Lidocaine w/Epi?
4.4 mg/kg
What is the max dose of Mepivicaine (Carbocaine)?
4.4 mg/kg
What is the max dose of Bupivicaine (Marcaine)?
1.3 mg/kg
What is the max dose of Septocaine (Articaine)?
7 mg/kg
2% LA = how many mg/ml?
20 mg/ml
1:100,000 Epi = how many mg/ml?
0.01 mg/mL = 10 mics/mL
What is the max dose of Epi for a healthy patient?
0.2 mg
What is the max dose of Epi for a cardiac patient?
0.04 mg
How many mg of local are in one carpule of Lidocaine 2%?
34: 20 mg/mL x 1.7 mL
What is the max dose of LA in 1 sitting?
300 mg (6 carpules)
How many carpules would you have to give to reach the max dose Epi for a healthy patient and a cardiac patient?
11 (healthy) : 0.2 mg/0.017mg = 11.7
2 (cardiac): 0.04mg/0.017mg = 2.35
How does Epi effect myocardium?
Increase cardiac output, stroke volume and O2 consumption.
Decrease overall efficiency of myocardium.
Is an increase in BP, HR, and RR a mile to moderate or moderate to severe sign of OD?
Mild to moderate
What are signs of moderate to high OD signs?
Tonic-clonic seizure
CNS depression
Decrease in BP, HR, RR.
Ester of benzoic acid
Poor absorption
Localized allergic reactions:
Benzocaine
Poorly soluble in H20
Used in [5%]
Used for oral ulcerations, HSV, mucositis from Chemo/radiation:
Lidocaine
Rapid onset Duration up to 2 hrs (rapid absorption and slow elimination (toxicity). Metabolized in liver. Excreted in urine. Overdose uncommon
Cocaine Hydrochloride
What are the 3 divisions of the trigeminal nerve?
- Ophthalmic
- Maxillary
- Mandibular
Which areas are anesthetized by a PSA nerve block?
Pulpal and lateral gingiva to the MB cusp of 1st molar.
What are the 3 landmarks for the PSA?
- Zygomatic Buttress
- Depth of vestibule
- Maxillary tuberostiy
What is the direction of the PSA needle?
Posterior, superior, medial
Which areas are anesthetized by the ASA nerve block?
Pulpal and lateral gingiva and mucosa from central incisor to MB root of 1st molar.
What are the 4 landmarks of an ASA?
- Medial aspect of pupil
- Infraorbital notch
- Depth of mucobuccal fold
- 5 mm lateral to long axis 1st premolar
Which area is anesthetized by greater palatine nerve block?
Posterior hard/solft palate to midline.
What are the 3 landmarks of the greater palatine?
- Midline of palate
- 2nd max. molar
- Greater palatine foramen at the junction of maxillary alveolar process and palatine bone.
Which area is anesthetized by an incisive canal block?
Anterior hard palate (lateral –> lateral)
What is the landmark for incisive canal block?
Incisive papilla
Which areas are anesthetized by a 2nd division block?
All upper teeth and buccal/palatal mucosa on injected side..
What are the 4 landmarks for 2nd division block?
Same as PSA but higher and deeper.
What is the landmark for common infiltration?
Mucobuccal fold at or above apex of root.
Which areas are anesthetized by IA?
Pulpal anesthesia for all lower teeth on side injected.
Does not anesthetize posterior lateral gingiva (long buccal).
Does not anesthetize lingual, although lingual is commonly anesthetized at same time.
What are the 5 landmarks of IA?
- Depth of coronoid notch
- Pterygomandibular raphe
- Bisection of thumbnail lying in coronoid notch (or higher)
- Contralateral premolars
- Occlusal plane
What is anesthetized by long buccal nerve block?
Lateral gingiva in posterior mandible
What are the 2 landmarks for buccal nerve?
Anterior, lateral border of ramus.
Superficial
What is the Gow gates nerve block and what does it anesthetize?
V3 block.
All lower teeth on injection side and givingiva, palate, mucosa (except posterior buccal mucosa).
What are the 5 landmarks for Gow Gates?
- Lower border of tragus
- Corner of mouth
- Needle tip just below ML cusp of max 2nd molar
- Penetrate soft tissue just distal to 2nd molar
- Contact with neck of condyle
Which has a higher success rate, Gow Gates or IANB?
Gow Gates (95%) IANB (80%)
T/F: N2O is not metabolized by body and has no adverse effects on liver, brain, kidneys, or respiratory system:
T
What is the amount of lbs per square inch gauge in a tank of nitrous?
745 psig
What is D.I.S.S.
Diameter Index Safety System
What is the ratio of nitrous to oxygen?
4:2 (67% nitrous oxide)
What is diffusion hypoxia and how can it be prevented?
- less than 10% alveolar O2 concentration.
- 100% O2 at end for 3-5 minutes.
What is the range of FBS in the MU oral surgery department?
> 90 and
What is the range of safety for INR?
2.0-3.5
If greater than 3.5 manage with warfarin.