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415 Cards in this Set
- Front
- Back
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Out of all the '-cains' which one is the only vasoconstrictor?
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cocaine! All others are vasodilators
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Which to more people have allergy to, ester or amide?
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ester
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Which local anesthetics are esters and which are amides?
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- amIdes have an 'i' in the first part of their name. i.e. Mepivacaine.
esters: the only 'i' in their name is in the 'cain' part. |
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What is the gold standard for LA?
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Lidocaine. This was the first amide LA. AKA Xylocaine
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Describe the general effects of lidocaine
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- 3-5 minute onset
- 1 hour pulpal duration -3 hour soft tissue duration |
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What is pKa?
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pKa is the pH of a drug at which 50% is ionized, and 50% is neutral
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Ionized or neutral: which form traverses the nerve sheath and which actually blocks the Na+ channel?
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- It is the neutral drug that passes across the nerve sheath
- only ionized drug blocks the Na+ channels |
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What causes termination of action?
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Termination of action is due to redistribution (NOT metabolism). Diffusion away from the site of action. The vascularity of the injection site is a strong factor determining length of action.
-LA is only metabolized in the liver, it only gets there via redistribution |
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Besides blood flow, what impacts redistribution?
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- protein binging characteristics of the LA. Increased protein binding = increased duration of action, the LA sits in the area for longer
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Properties of LA governing performance
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PROPERTY------------------------------> CLINICAL CORRELATE
-Lipid solubility --------------------> Onset & potency - Protein binding ------------------> duration - Dissociation Constant (pKa) ----> Time of onset -Amide vs. Ester --------------------> Clearance & biotransformation |
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Where do esters and amides get metabolized?
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esters: enzymes in the blood
amides: liver only |
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How does epi cause vasoconstriction?
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- stimulates Alpha receptors
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3 rationales for addition of epi in LA
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1. vasoconstriction keeps LA in local area for longer
2. reduces systemic toxicity by decreasing the rate of systemic adsorption, a given dose of local aesthete will be absorbed over a longer period of time, making the LA safer. 3. reduces bleeding in operative area |
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What is the 'trick' for calculating how many mg of LA in a given injection of X mL?
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- Add a '0' to the %# of LA to give mg/1mL
-ie. 2 % lidocaine= 20 mg/ 1 mL - 1 cartridge = 1.8 mL -therefore, (20 mg/mL) X 1.8 mL = 36 mg/ 1 cartridge |
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To calculate amount of anesthesia given:
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-one carpule = 1.8 ml
-% [ ] of anesthetic x 1.8 ml = # of mg of anesthetic/ carpule - ex. 1/3 of 2% Lido given - 20 (% x 10) x 1.8 = 36 ml of Lido - 36 ml / 3 = 12 mL Lido given |
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To calculate amount of Epi in one carpule
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-depending on epi listed on carpule:
- 1:100 000 = 1/100 = 0.01 X 1.8 = 0.018 mg epi -1: 50 000= 1/50 = 0.02 X 1.8 = 0.036 mg epi - 1:200 000 = 1/200 = 0.005 X 1.8 = 0.009 mg epi |
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To calculate amount of Epi given
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- more than 1 car pule: multiply # of carps by mg of epi per carp
- ex. 3 carps x 0.018 mg epi = 0.054 mg epi given - Less than 1 carp: divide amount given by mg of dpi in carp - ex. (1/3 given) 0.018mg epi = 0.006 mg dpi given |
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What is the max epi allowed to be given to a patient with cardiovascular disease?
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-0.04 mg
- that is 2 carps of 2% Lidocaine (0.036 mg dpi) |
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What was the first local anesthetic?
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topical cocaine
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What was the first nerve block ever done?
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Inferior alveolar nerve block
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Which local anesthetic is the only vasoconstrictor?
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only vasoconstrictor= cocaine
-all others= vasodilators |
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2 interesting things about Lidocaine
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- first amide local anesthetic
- is the 'gold standard' -AKA Xylocaine |
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the 'specs' of Lidocaine
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- 3-5 minute onset
- 1 hour pulpal duration - 3 hour soft tissue duration |
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The options with Mepivicaine
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- 3% plain
- 2% with levonordefrin 1:20 000 |
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Prilocaine options
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- 4% plain or
-4% with 1:200 000 epi |
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Buvicaine options
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-0.5% with 1:200 000 epi
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Articaine options
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-4% with 1:100 000 epi
- 4% with 1:200 000 epi - This is the most popular in north america, that doesn't mean its the best, it just has lots of marketing, it's more expensive (so ppl 'think' its better), its just as good as lidocaine |
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Pharmacology of local anesthetic chemical structure
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-aromatic ring= lipophilic
-intermediate linkage= ester or amide -terminal amide= either tertiary form (lipid soluble) or quaternary form (+ charged and water soluble) |
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T or F: all nerves are susceptible to blockade regardless of their function, this includes motor and sensory.
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True
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Which fibbers get frozen first?
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C fibers get frozen first (before A fibbers) because they are smaller in diameter. There are no B fibers in the mouth.
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Why does soft tissues freeze before pulpal tissues
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- The fibbers for soft tissues are on the outer surface of the nerve, whereas the pulpal fibbers are near the middle of the nerve, it takes longer for the LA to diffuse and penetrate to the middle of the nerve
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define pKa
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-pKa is the pH of the drug at which the drug is 50% ionized, and 50% neutral.
-pKa is fixed, specific value for any given drug -BUT the pH is variable depending upon many factors |
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pKa for lidocaine
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7.8
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Describe which form (charged or neutral) crosses the nerve sheath, nerve membrane and which blocks ion channels
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-neutral crosses the nerve sheath and membrane
- each time it crosses a barrier it has to re-equilibrate, depends on the pH of the fluid in each space - ionized actually blocks sodium channels |
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Termination of action is due to
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-redistribution (NOT metabolism)
- diffusion away from the site of action -therefore really depends on the vascularity of the site -Increased blood flow= shorter duration of action |
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Redistribution depends on:
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- vascularity
- protein binding characteristics of LA: increased protein binding= increased duration of action, sits in that area for longer |
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Clinical correlate of: lipid solubility
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onset and potency (% solution)
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Clinical correlate of: protein binding
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duration
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Clinical correlate of: dissociation constant (pKa)
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- time of onset (more neutral molecules that redistribute into nerve quicker)
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Clinical correlate of: amide vs ester
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- clearance and biotransformation (esters get metabolized in the blood, thought to be safer, less likely to OD BUUTT more patients are allergic. Amides metabolized in liver)
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How can you tell by the name of a LA if its an ester or amide?
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there is a 'i' in the name before the 'caine'.
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Primary rationale and mechanism for the addition of vasoconstrictors
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-to increase the duration of effect
- Mechanism: alpha stimulation--> arteriolar constriction--> decreased redistribution |
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Secondary rationales for addition of epi to LA
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-Reduce systemic toxicity by decreasing the rate of systemic absorption
- A given dose of LA will be absorbed over a longer period of time -Makes the local anesthetic SAFER -Reduces bleeding by decreasing blood flow to operative area (only infiltration) |
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Can you give LA with epi to cardiovascular pt?
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- YES! just limit the about give to ~2 carpules of 1:100 000 or 1 car pule of 1:50 000 or 0.04 mg. Why? bc you can't get complete LA with plain LA, so they feel pain--> their body releases way more dpi than you could give in a LA
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Lidocaine (2% and 1:100 000 epi). How many mg lidocaine and how many mcg of epi in 2.5 cartridges?
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90 mg lidocaine
45 mcg epi |
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1: 100 000; 1: 50 000; 1: 200 000= ? many mcg/mL?
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1:100 000= 10 mcg/mL or 0.01 mg/mL
1:50 000= 20 mcg/mL or 0.02 mg/mL 1:200 000= 5 mcg/ mL or 0.005 mg/mL |
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1: 100 000 epi = _____mg /cartridge
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0.018mg/cartridge
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1: 50 000 epi = _______mg/ cartridge
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0.036mg/cartridge
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2 things that our syringes must be able to do
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1. must be capable of aspiration
2. must be sterilizable or disposable |
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Tell me about the gauges of needles
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The larger the # of the gauge, the smaller the diameter of the needle
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How long is a long needle? short needle?
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-long= 32 mm
-short= 20 mm |
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Where is the most rigid part of the needle?
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at the hub, that is why it is also the weakest and will always break there.
***NEVER insert a needle into the tissue to its hub, unless it is absolutely essential for the success of the injection |
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Which needle is most likely to break?
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-30 gauge short
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Why is there no difference in efficacy and no difference in pain between 30 and 25 gauge needles
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- once you get smaller than 25 gauge, the pain receptors can't notice a difference
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Why is large gauge (25) preferred over small gauge (30)
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Large gauge is preferred because:
- less deflection (Small gauge bends when you go thru muscle, therefore does not get to the point you want!!= failed block - greater accuracy -easier aspiration -LESS CHANCE OC BREAKAGE |
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If you could only choose one needle to complete every block, which would you choose?
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- 25 gauge long
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How often should you change needles?
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-for sure: btw every patient
- every 3-4 penetrations |
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Shelf life of LA
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plain: 36 months
vasopressor: 18-24 months |
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Ingredients of LA containing vasopressor
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- LA drug
- vasopressor - sodium chloride - citric acid (lowers pH) - distilled water - sodium (meta)bisulfite- an antioxidant |
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Ingredients of LA plain
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-LA drug
- sodium chloride (LA is actualy a power, needs to be in a salt soln.) - distilled water |
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How long should topical be applied before injection?
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at least 2 mins
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If you do a supraperiosteal injection (AKA infiltration), what do you expect to be frozen?
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Infiltrations are for an maxillary tooth
- freezes the buccal soft tissues, supporting bone, pulp of that specific tooth -NO PALATAL SOFT TISSES OR BONE -Therefore, if you need to extract that tooth, or do anything on the lingual, you also need to freeze the lingual/palatal |
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The full spects of Supraperiosteal/ infiltration injection
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- indication: 1-2 maxillary teeth
-volume:0.6 mL or 1/3 of cartridge -Needle: 27 g short -Target: apex of tooth |
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Obv you should inject slowly. But HOW slowly?
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rate of 1 min/cartridge
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Describe HOW you would do a supraperiosteal injection?
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- insert needle into the height of MB fold over tooth
- advance needle until needle tip is at or above the apex of tooth, 3-4 mm past insertion - aspirate -deposite 0.6 mL |
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Where would you use a PSA block? what does it freeze?
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- for MAX molars
-Freezes buccal soft tissues, supporting bone -pulpal: max molars: 3rd, 2nd and part of 1st molar ( misses MB ~25% of the time) -NO PALATAL SOFT TISSUES OR BONE |
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What 3 words do you need to remember about the PSA block?
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Inwards, upwards, backwards
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The specs of PSA block
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Needle: 25 or 27 short
Insertion: mb fold over 2nd molar, short= 3/4 the needle, long=1/2 the needle Target: pterygomaxillary space volume: 0.9- 1.8 mL hematoma?= over insertion |
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Describe how you'd perform a PSA block?
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- insert needle in mb fold adjacent to max 2nd molar, distal 1/2
- bevel towards bone - direct the needle in a inward, upward and backward direction, 45 degrees in all planes - advance needle 16 mm - aspirate x 2 - slowly deposits 0.9mL (1/2 the cartridge) |
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What does the ASA block freeze?
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- MAX incisors, canine, premolar on that side
-buccal soft tissues - supporting bone - soft tissues on the anterior portion of the face -NO palatal soft tissues or bone |
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What pulpal anesthesia will you get from a ASA block?
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- incisors, canine, premolars
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What soft tissue anesthesia will you get from ASA block?
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- buccal soft tissues and bone over teeth
- lower eyelid, upper lip, lateral nose |
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The specs of ASA block
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- Needle: 25 long
-Insertion: mb fold over 1st premolar - Target: infraorbital foramen -Volume: 0.9 mL to 1.2 mL (1/2-2/3 of cartridge |
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Describe how you'd do a ASA block
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- place finger in IO foramen
- insert in mb fold over 1st premolar - advance until bone contacted - check syringe orientation -aspirate x2 -slowly deposit 0.9-1.2 mL -apply finger pressure for 2 minutes |
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What will you freeze with a palatal injection?
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- palatal soft tissues and bone
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2 types of anesthesia you can give your pt BEFORE an injection
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-topical
-pressure (before/during). Pressure with a Q-tip till blanching, place needle in this blanched tissue |
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Where will you freeze with a greater palatine nb?
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- posterior portion of hard palate and overlying tissues
-anteriorly to the 1st premolar -medial to midline |
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The specs on greater palatine nb
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- needle: 27 short
- insertion: palate anterior to greater palatine foramen, find foramen with Q-tip, usually btw 2nd and 3rd molar, blanching pressure with Q-tip, injected anterior to Qtip - Target: Greater palatine n - volume: 0.45-0.6 mL (1/4 cartridge) |
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Describe in detail how you would perform the greater palatine nb
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-Topical just anterior to the gp foramen
- pressure anesthesia on foramen angle across mouth - syringe at topical site -Maintain pressure, advance to bone -Aspirate 2X - deposit anesthetic |
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What will be frozen with a nasopalatine nb?
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- anterior portion of hard palate from mescal of right 1st premolar to medial of left 1st premolar
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specs on nasopalatine nb
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Needle: 27 short
Insertion: palatal mucosa lateral to incisive papilla Target: incisive foramen, beneath the incisive papilla volume: 0.45 mL |
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How much LA do you inject for: Supraperiosteal?
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0.6mL
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How much LA do you inject for: PSA
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0.9mL
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How much LA do you inject for: ASA
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0.9mL
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How much LA do you inject for: Greater palatine
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0.45 mL
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How much LA do you inject for: Anterior palatine
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0.45 mL
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Why don't you do infiltration blocks on the mandibular arch?
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because the cortical bone is very thick and dense and the LA doesn't reach the nerve.
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Which 2 injections do you always do together?
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Inferior alveolar block and the long buccal block
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Inferior alveolar nb: what does it freeze?
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- mandibular teeth to midline
-buccal soft tissues anterior to mandibular 1st molar -body of mandible, inferior portion -anterior 2/3 of tongue - lingual soft tissues, periosteum |
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In order to block nerve condition, how much nerve needs to be anesthesized?
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- 10 mm of nerve, which is 3 nodes of Ranvier
- 10 mm is quite long, which is why we want increased volume of anesthetic, not higher concentration for successful blockage. |
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The specs of the inferior alveolar nb
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-Needle: 25 long
- Insertion: soft tissues on the medial border of rams - Target: IA nerve on lingual aspect of ramus prior to entering mandublar foramen -Volume: 1.5 mL |
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What is the 'rule of thumb' if you are not successful on a IA nb?
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-if you missed the block, re-try but higher up on the ramus as this is the most likely alternate anatomy
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Describe how you would perform a IA nb?
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- place finger in coronoid notch
-visualize a line from your finger to the pterygomandibular raphe - Pick a spot about half way from your finger to the raphe, (~ 4-5 mm )anterior to the raphe - Place syngrine barrel in corner of mouth on opposite side, as far as possible - Advance needle to bone ( ~ 20-25 mm) - withdraw 1 mm - aspirate x 2 - deposite 1.5 mL |
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What does it mean if the needle hits bone 'to soon' when trying to do a IA nb?
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The needle tip is too anterior
- withdraw slightly, angulate the needle tip more posteriorly, then readvance to correct depth ( 20-25 mm ) |
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What does it mean if the needle doesn't hit bone when doing a IA nb?
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The needle tip is too posterior
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What should you do following completion of IANB?
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Seat patient comfortable upright, speeds onset of anesthesia
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What does the long buccal nb freeze?
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- soft tissues and periosteum adjacent to mandibular molar teeth
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When and how should a long buccal block be done?
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- after doing a IANB, save 1/4 of the cartridge, pull out and place back in at buccal nerve all in one motion
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the specs of buccal nb
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-Needle: 25 long
-Insertion: mucus membrane distal and buccal to last mandibular molar, going to hit bone almost right away, will only insert ~ 3 mm - Target: buccal nerve passing over border of rams -Volume: 0.3 mL |
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What does the Gow-Gates freeze?
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- inferior alveolar
-lingual -auriculotemporal -mylohyoid nerve - long buccal (75% of time) |
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What is the target point for the needle tip of the Gow Gates injection?
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- The medial aspect of the anterior portion of the condyle
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What does the patient do to help ensure the success of the Gow Gates injection?
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- open their mouth as wide as possible!!! This causes the condyle to rotate and translate forwards and downwards.
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Describe how you would perform a Gow Gates injection?
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-palpate condyle with the fingers while thumb retracts cheek
-Beginning from the contralateral canine, the needle is positioned so that a puncture point is made in the muccobuccal soft tissues adjacent to the distobuccal cusp of max 2nd molar -Needle is inserted to 30mm, contacting bone. -Injection must bot be performed unless bone is contacted, which prevents injection into the capsule of TMJ |
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How long does it take for the Gow Gates to freeze?
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10 mins, relatively long
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What injection does this describe?
- only blind mandibular block - dont hit bone - closed mouth technique |
Akinosi-Vazirani
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The spects of the Akinosi-Vazirani block
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- Needle: 25 long
- insertion: medial aspect of the ramus adjacent to max tuberosity at the height of the mucogingival junction of last max molar - Target: V3 on lingual aspect of man ramus - volume: 1.8 mL |
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What does the Akinosi-Vazirani block freeze?
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- inferior alveolar
-lingual - long buccal |
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When would the akinosi Vazirani block be useful?
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- uncooperative children
- patients with trismus |
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Describe how you would perform a Akinosi- Vazirani block?
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- Long needle inserted parallel to the max occlusal plane at the level of the max buccal vestibule
- depth of penetration is approx. half the mesiodistal length of the ramus (25 mm in adults, less in kids) - Endpoint: just superior to lingula ( hub of needle adjacent to mesial aspect of the max 2nd molar at height of mucogingival junction) |
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Why is the Akinosi-Vazirani block said to be 'blind'?
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because no bony endpoint exists
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The apecs on the Akinosi-Vazirani block
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-Needle: 25 long
- Insertion: medial aspect of ramus adjacent to max tuberosity at height of mucogingival junstion of last max molar - Target: V3 on lingual aspect of mand ramus - Volume: 1.8 mL |
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What does the incisive nb freeze?
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-Buccal mucous membrane anterior to mental foramen to midline
-skin of lower lip and chin -Pulp of incisors, canine and premolars |
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The specs of the incisive nb
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- Needle: 27 short
- Insertion: MB fold at or anterior to mental foramen -Target: mental nerve as it exits mental foramen - Volume: 0.6 mL - put finger pressure on foramen after to push LA into foramen |
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Describe how you would perform a incisive nb
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- Insert needle in buccal fold and advance towards mental foramen
- Aspirate X2 - Deposite 0.6 mL - finger pressure for 2 minutes placed over LA solution, forcing ti into the mental foramen |
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How much LA do you inject for: IANB
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1.5-1.8 mL
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How much LA do you inject for: long buccal nb
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- 0.3 mL
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How much LA do you inject for: mental / incisive nb
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0.6 mL
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How much LA do you inject for: Gow Gates mandibular nb
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1.8-3.0 mL
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How much LA do you inject for: Akinosi- Vazirani
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1.8 mL
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Which ASA levels can dentists treat in their office?
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ASA 1, 2, and select 3
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What is ASA 1?
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Normal, healthy.
-no systemic disease, -don't smoke, dont take medication |
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What is ASA 2?
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Mild systemic disease, but does not affect the way they live
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What is ASA 3?
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-Severe systemic disease, effects the way their live their life
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What is ASA 4?
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Incapacitating systemic disease
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What is ASA 5?
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24 hours to live
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What is ASA 6?
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organ harvesting
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What is ASA E?
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Emergency
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What sort of diseases would place a pt into ASA 2?
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-CVD: controlled hypertension
- Respiratory: asthma, smoker - Liver/Kidney: asymptomatic hep b and c -Endocrine: Controlled type 2 diabetes/hyper-hypothyroidism -Neurological: ADHD, depression |
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What sort of diseases would place pt into ASA 3?
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-CVD: controlled angina, aortic stenosis, pulmonary stenosis
- Respiratory: moderate asthma, taking steroids - Liver/kidney: Pt on dialysis -Endocrine: controlled type 1 diabetes |
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What sort of diseases would place a pt into ASA 4?
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- CVD: uncontrolled angina, critical aortic stenosis, pulmonary stenosis
- Respiratory: severe asthma - Liver/ Kidney: end stage liver, kidney failure -Endocrine: uncontrolled type 1 diabetes, uncontrolled hyperthyroidism |
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What constitutes uncontrolled angina?
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at rest, at night, more frequently than usual
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If a pt check off 'yes' to a systemic disease, what sort of probing questions should you ask them to investigate further?
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- stability, severity, treatment, complications
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Important questions to ask about hypertension
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- Has your GP every told you that you have high blood pressure?
- When were you diagnosed? -How often do you visit your GP? - home monitoring? - how long have you been on your current medications? - do you take them regularly? - any end organ damage? severity? |
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Types of 'cardiac pts'
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- hypertension
- acute angina - CVA in past 6 months - congestive heart failure - cardiac dusrhythmias - hyperthyroid (Graves Disease) |
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How does epi affect the heart?
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-increases heart rate, stroke volume, systolic blood pressure, myocardial oxygen consumption, cardiac automaticity
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Increased blood dpi will cause sequential changes in the CVS
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1 cartiridge of 1:100 000: increased heart rate
2 '' '' : increase systolic blood pressure 3 '' '' : increase diastolic pressure |
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What is bisulphate in LA?
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- bisulphate is an anti-oxidant, (not a preservative), used to keep the epi from oxidizing. Some people may be allergic to this; if that is the case, give them 'plain' LA
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What is the max dose of epi recommend for a normal pt ( ASA 1 or 2) from the New York Heart Association?
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- no more than 0.2 mg of epi in any form
- that is quite a bit, there is 0.3 mg in an epipen. |
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In 1 cartridge of 1.8 mL, how much epi is there if: 1: 100 000 epi?
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0.018mg epi
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In 1 cartridge of 1.8 mL, how much epi is there if: 1: 200 000 epi?
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0.009mg epi
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In 1 cartridge of 1.8 mL, how much epi is there if: 1: 50 000
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0.036 mg epi
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The typical [ ] of vasoconstrictors contained in local anesthetics are not contraindicated with CVD as long as:
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1. preliminary aspiration is practiced
2. monitor blood pressure before and after 3. the agent is injected slowly 4. the smallest effective dose is administered |
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What is max dose of of epi for a CVD pt in ASA 3 or 4?
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0.04 mg
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If 0.04 mg is the max epi a pt with ASA 3/4 CVD, then what is the max # of LA cartridges they can have depending on the epi concentration?
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1: 200 000=4 cartridges total ( 0.09 mg/ cartridge)
1: 100 000 = 2 cartridges (0.018 mg/cartridge) 1: 50 000= 1 cartridge (0.036 mg/cartridge) |
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T or F: In persons older than 50 years, systolic blood pressure greater than 140 mm Hg is a much more important CVD risk factor than diastolic BP
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True
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What is the 'rule of 2's' for Steroids?
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Red flag if pt has been on steroids for 2 weeks or more in the past 2 years
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Is local anesthesia, Nitrous oxide or oral/ IV sedation a risk for malignant hyperthermia?
|
No, those are all considered safe. only succinylcholine, inhaled vapors of sevoflurane, isoflurane, halothane, and desflurane are risks/triggers
|
|
|
What ASA class is a pregnant patient?
|
ASA 2
|
|
|
Discuss some steps taking with haemorrhagic disorder patients
|
- Elevate missing factor to 30%
- Aspirate repeatedly - slow injections - supraperiosteal rather than blocks - intraligamentary -Intraosseous - consider referral to hospital -blood work done the day of |
|
|
Is 4% Articaine better than 2% lidocaine?
|
- no difference btw in freezing, but there was 0.9% greater paresthesia incidence with articaine (higher%)
|
|
|
What is paresthesia?
|
- an abnormal sensation of the skin, such as numbness, tingling, pricking, burning or creeping on the skin that has no objective cause
|
|
|
Name some causes of Mandibular block failure
|
- presence of inflammation
- incorrect needle placement - anatomic variation - fear and anxiety |
|
|
How does the prescence of inflammation interact with LA?
|
-inflammed tissue has a low pH (5-6)
- non-inflamed tissue has pH (7.3) - Inflammation also leads to increased blood flow in the tissue - provide nerve block anesthesia at a site distant to the inflammation to avoid the decrease in pH - morphological changes occur along the nerve some distance away from the inflammation - mediators of inflammation may affect nerve transition and local anesthetics |
|
|
If a pt were to have anatomical variation in their nerves to freeze, what are 2 likely ones?
|
-mylohyoid nerve
- branches of the V3 nerve |
|
|
Describe the mylohyoid nerve and what it MIGHT innervate
|
- Mylohyoid N enters the mandible through 'retromental foramina' through lingual aspect of the mandible
-caries sensation anywhere from 1st molar to incisors -branches from IAN anywhere from 5-23 mm -mylohyoid innervation of mandibular teeth 60% |
|
|
Describe the most likely anatomical variation of branches of V3
|
-Branches of V3 enter mandible high and anterior to the mandibular foramen and innervate 2nd and 3rd molars
- branches that enter the mandible in the retromolar fossa area and innervate the 1st and/or 3rd molar |
|
|
What is the 'Stabident' system?
|
-freeze attached gingiva
- drill a hole through cortical bone into cancellous bone - needle inserted into hole and LA is injected into cancellous bone for almost instant and deep pulpal anesthesia |
|
|
What is 'Oraverse' and what does it do?
|
- a nonselective alpha-adrenergic antagonist
- increases blood flow to the area, thereby washes the LA away -Pt is back to having feeling in 1/2 the time |
|
|
Which injection was found that using articaine was MUCH more efficacious than lidocaine? (both same about of epi)
|
-infiltrations!!
IE: If you are doing an IAN block and want a higher % of being frozen, add a infiltration -the IANB should be done with 2% Lidocaine, and the infiltration should be done with 4 % articaine. |
|
|
What 2 main systemic complications are we worried about when administering LA to a patient?
|
--Allergy/ Psychogenic reactions
-toxic overdose |
|
|
When do most LA complications occur?
|
-within 5-10 minutes after injection
|
|
|
What do you have to chart after giving a LA injection
|
- type of block or infiltration
- length /gauge of needle used -amount of anesthetic used (in mg) - type of anesthetic used - concentration of vasoconstrictor - any adverse reactions |
|
|
Break time :) ok no question on this card, just read an example of how to chart an injection
|
-R-IANB with a 25g long needle. 36 mg of 2% lidocaine with 1:100 000 epi. positive aspiration, re-positioned, negative aspiration
|
|
|
What would a facial nerve palsy from a IAN block look like?
|
- generalized weakness of the ipsilateral side of the face
- inability to close the eyelids - obliteration of the nasolabial fold drooping of the mouth tot he unaffected side |
|
|
What would a facial nerve palsy from a PSA block look like?
|
-possibly caused by retrograde injection into the PSA artery--> middle meningeal artery--> petrosal artery branches--> facial nerve
-temporary blindness (due to a large quantity of LA diffusing through the inferior orbital fissure and coming into contact with the optic nerve) - abducence nerve palsy: double vision, limitation of abduction. |
|
|
T or F?: Vasoconstrictors should be included in ALL LA soln. unless there is a compelling reason for their exclusion
|
True
|
|
|
What are 2 reasons why you would use a PLAIN LA?
|
1. Short duration of action desired
2. Medical contraindication |
|
|
In most individuals, even those with heart disease, the CVS effects of conventional doses of adrenergic vasopressors are of little practical concern. However, when can they result in potentially serious outcomes?
|
-accidental intravascular injection
- unusual patient sensitivity - unanticipated drug-drug interactions - excessive doses |
|
|
What are some main categories where you should stop and consider if there is a contraindication to vasoconstrictors in dentistry?
|
- CVD
- hyperthyroidism, diabetes, sulfite sensitivity, cortico-dependent asthma, and pheochromocytoma - pharmacologic interactions |
|
|
Name some absolute contraindications for LA under the category of CVD?
|
- unstable angina
- recent myocardial infarction - recent coronary artery bypass surgery - refractory dyshythmias - untreated/uncontrolled severe high blood pressure - untreated/uncontrolled congestive heart failure |
|
|
Name some relative contraindications for LA under the category of pharmacologic interactions
|
- TCA (because of Levonordefrin)
- Monoamine oxidase inhibitors (COMT??) -Cocaine abuser (Causes stroke when mixed with LA) |
|
|
Which is the most missed block?
|
IAN
|
|
|
When would you use a 20% lipid emulsion
|
- to treat a severe, systemic drug toxicity or poisoning
|
|
|
What causes termination of action?
|
-Redistribution. Diffusion away from the site of action. Vascularity of the site. Maxilla vs. mandible. (max more vascular?)
-Increased blood flow = shorter duration of action -NOT metabolism. NO. Not EVER. - |
|
|
Where are amides metabolized? by what?
|
- Biotransformation occurs by HEPATIC microsomal enzymes
|
|
|
What is the half life of most amides?
|
- Lidocaine, Mepivacaine, Prilocaine= 90 minute half life
|
|
|
How long of duration do you get pulpal anesthesia from common amide LA?
|
- Most are 60 minutes of pulpal anesthesia
|
|
|
What is the pH of common LA?
|
plain= 6.5
Vasoconstrictor= 3.5 |
|
|
Why would a LA with a vasoconstrictor be more painful on injection than a plain LA?
|
- LA with vasoconstrictors are more acidic, and therefore may irritate the tissues more, therefore more painful on injection
|
|
|
What is the shelf life of LAs?
|
- plain= 36 months
- Vaso= 18 months |
|
|
What is pKa again and what does it mean for the LA molecules if they are in an environment that is more acidic than it's pKa?
|
pKa= that pH at which 50% of the anesthetic molecules exist in a charged (RNH+) form and 50% exist as uncharged molecules (RN).
-If in more acidic environment than pKA, there will be more charged molecules -Therefore, the lower the pKa value, the faster the onset of anesthesia, because there will be more neutral molecules in the same human tissue environment as compared to using a LA with a higher pKa. |
|
|
The _______ the pKa value of LA, the faster the onset of anesthesia
|
LOWER
|
|
|
What determines the time to onset of a LA?
|
pKa
|
|
|
What determines the POTENCY of a LA?
|
lipid solubility.
-The more lipid soluble a LA is, the greater its potency because a greater % of molecules diffuse through the lipid membrane |
|
|
What is the pH within a nerve?
|
7.37
|
|
|
How does a charged molecule of LA cause freezing?
|
- RNH+ enters Na- channel and attaches to receptor site
-RNH+ blocks entry of Na into interior of nerve when stimulation occurs, preventing propagation of nerve impulse -This produces a non-depolarizing section of nerve, stopping the propagation of a electrical impulse. |
|
|
What affects duration of anesthesia?
|
degree of protein binding, the more protein binding, the longer the LA will stay in one area.
|
|
|
How long does pulpal anaesthesia last? soft tissue anesthesia? (2% lidocaine with vasoconstrictor)
|
pulpal= 60 mins
soft tissue= 5 hours |
|
|
When will you get peak blood levels of LA if using:
-plain? - with epi? |
-plain= 5-10 minutes
- with epi= 20-30 mins |
|
|
If a pt is allergic to one LA, are they allergic to all LA?
|
-Not necessarily. All esters break down into the same PABA metabolite, therefore if pt is allergic to 1 ester, they will be allergic to all esters.
-Each amide breaks down into different metabolites, therefore you cannot be allergic to ALL amides. |
|
|
If you wanted to use a short acting LA, what would you use?
|
- short acting= 30 mins
- mepivacaine (3%) -prilocaine (4%) |
|
|
If you wanted to use a long acting LA, what would you use?
|
-long acting = >90 mins
-bupivacaine (0.5%) w 1:200 000 epi |
|
|
If you wanted to use an intermediately duration LA, what could you use?
|
- intermediate =60 mins
-Lidocaine 2% (1:50 000 or 1: 100 000 epi) - Mepivacaine 2% ( levonordefirin 1:20 000) - Prilocaine 4% ( epi 1:200 000) - articaine 4% ( epi 1:00 000 or 1: 200 000) |
|
|
Which [ ] of epi is safer to use?
|
1:200 000 ( lower concentration)
- Interesting fact: There is no difference in duration of action when there is different [ ] of epi bc duration of action depends on protein binding |
|
|
Out of 100 patients, how many would you expect them to react to LA injection 'normally'? hypo? hyper?
|
normal= 70%
hypo=15% hyper= 15% |
|
|
What are 2 explanations when a pt 'cannot get frozen'
|
- anatomical variation
- infection: decrease in pH, therefore less neutral molecules, more charged molecules, less available neutral molecules to cross the membrane |
|
|
What are some factors to consider that affect the duration of anesthesia in a pt?
|
- individual variation in response
- accuracy in deposition of drug - status of tissue at site (vascularity, pH) - anatomical variation -Type of injection (block vs. infiltration) |
|
|
T or F?: For ALL LA, both hard and soft tissue anesthesia will be of longer duration via NERVE BLOCK than via INFILTRATION?
|
True
|
|
|
Lidocaine is also known as
|
-xylocaine
-Octocaine -Alphacaine -ligonospan |
|
|
How many mg of Lidocaine is there in 1 cartridge of 2% lidocaine?
|
-2%-->add a '0'--> 20mg/mL
-1.8mg/cartridge, therefore 1.8 X 20mg/mL= 36mg |
|
|
What is the 'onset of action' time for Lidocaine?
|
3-5 minutes
|
|
|
Lidocaine: duration of action?
|
- pulpal: 60 mins (infiltration)
-pulpal: 85 min (inferior alveolar block) -soft tissues: 200 mins |
|
|
What is the MAX recommended dose of Lidocaine?
|
- 7.0 mg/kg ( no difference if adult of child)
- Absolute max= 500 mg or 13 cartridges (based on a 70 kg adult, if you have a small female, weight her) |
|
|
How many mg is there in 1 cartridge of 3# mepivacaine?
|
3%--> add a '0'--> 30 mg/mL
-1.8 mL in a cartridge--> 30 X 1.8= 54 mg/cartridge |
|
|
What is the duration of onset in 3% mepivacaine?
|
3-5 minutes
|
|
|
What is the duration of anesthesia of 3% mepivacaine?
|
pulpal: (infiltration = 25 minutes) ( IAN= 40 minutes)
- soft tissues: 90-165 min |
|
|
What is the MRD of 3% Mepivacaine?
|
- 6.6 mg/kg
- absolute max= 400 mg or 7 cartridges |
|
|
Which is safer to use: epinephrine or levonordefirin?
|
Epi is safer....
- Levonordefirin prevents the reuptake of epi. Any pt on SNRi or TCA you will see a spike in the BP! Do NOT use Levonordefirin on a pt taking SNRi or TCA. Take pt hx!! |
|
|
Talk a little bit about the safety of Levonordefrin in cardiac pt...
|
-similar in structure to norepinephrine
- incorrectly considered to be safer for the 'cardiac pt' as it dow not increase heart rate - However, it does increase blood pressure - can have exaggerated response with TCA SNRi or Duloxetine - similar in strength to 1: 100 000 epi |
|
|
Which ASA class can you give LA to? Vasopressor?
|
LA: can give to all ASA classes
Vasopressor: only give to ASA 1, 2, and some 3, but limit for CVD) |
|
|
Sensitivities: Sulfa, sulfite, sulfur?
|
Sulfa: in antibiotics
Sulfite: in red wine Sulfur: in articaine (CANNOT be allergic) |
|
|
If a pt has a sulfite sensitivity, which LA could you NOT give?
|
Do not give any vasoconstrictors!! therefore can only use PLAIN LA
|
|
|
If a pt is on a TCA antidepressant, what would you avoid and why?
|
- Avoid levonordefrin, which is only found in 2% mepivacaine
-Levonordefrin acts like norepinephrine. The TCA prevents the re-uptake of norepinephrine, and therefore prevents uptake of levonordefrin too. -will cause an exaggerated BP response |
|
|
If a pt is on Monoamine oxidase inhibitors, what is their contraindication?
|
- MAO breaks down epi intraneuronally.
-COMT breaks down exogenous epi - Therefore, if on MAOi, it is okay to give pt epi bc it is broken down by COMT |
|
|
Why would you not give a cocaine user EPI?
|
- cocaine is a vasoconstrictor, epi is a vasoconstrictor, therefore may constrict blood vessels too much and cause stroke
- cocaine prevents the reuptake of norepinephrine, and therefore probably epi too--> too much vasoconstriction |
|
|
What are 3 things you would consider when deciding on which LA to use?
|
- duration of treatment/anesthesia required
- medical contraindications - need for hemostasis |
|
|
Which concentrations of epi provide hemostasis?
|
1:50 000, 1:100 000= adequate
1:200 000= inadequate |
|
|
What is the metabolite in ester LA that people are allergic to?
|
- Para-aminobenzoic acid (PABA)
|
|
|
If pt is 'allergic' to LA, what ingredient are they most likely allergic to?
|
- the 'other' ingredients
-Sodium metabisulfite: is an antioxidant included in ALL LA cartridges containing a vasopressor to slow the oxidation of the vasopressor - This is very unlikely (they are probably just confused btw sulfa (antibiotics) and sulfites (LA) -but just to be safe, use plain instead |
|
|
There is physiological different in a true allergy rxn and a psychogenic rxn. Describe a true allergic rxn
|
--puritus (itchiing)
- urticaria (hives) - angioedema (swelling) - difficulty breathing (laryngeal edema and/or bronchospasm), -Shock may develop within another 1-2 mins |
|
|
There is physiological different in a true allergy rxn and a psychogenic rxn. Describe a psychogenic reaction (AKA panic attack)
|
- anxiety induced
- syncope -hyperventilation - nausea -vomiting - alterations in heart rate and BP (but still ~ normalish) |
|
|
What would the BP be like in a anaphylactic rxn?
|
- BP DROPS (like it's hot). to like ~60/40
|
|
|
What is the MAX dose of LA you can give for kids?
|
7 mg/kg ( same for everyone!!)
-if |
|
|
Algorithm of ALL medical emergencies:
|
P: phone EMS
A: airway B: Breathing C: circulation D: |
|
|
The most common cause of cardiac arrest in healthy children is:
|
airway obstruction
|
|
|
Irreversible CNS damage develops with anoxia in ____ minutes
|
3 minutes
|
|
|
Toxicity of :A: as blood levels of LA increase, what systems are effected first?
|
1. central nervous system (seizure)
2. CVS (heart stops) |
|
|
Describe the progression of CNS LA toxicity
|
- biphasic (stimulation/depression)
- depression of cerebral inhibitory centres - upopposed facilitatory neurons causing random stimulatory firing of the neurons in the brain producing tonic-clonic seizures -respiratory center depression - increased oxygen consumption of tonic muscles -progression to hypoxia, cyanosis, cardiac arrest |
|
|
how many mcg/ml are found at each of the 3 stages of CNS toxicity?
|
- 0.05 - 4 mcg/ml: anticonvulsant and sedative effects
- 4-7 mcg/ml: mild CNS stimulatory signs - 7.5-10 mcg/ml: generalized tonic-clonic seizures |
|
|
Mild signs of CNS stimulation from LA OD
|
- talkativeness
-slurred speech -apprehension - localized muscle tqitching - lightheadedness and dizziness - circumoral numnbess / tongue numbness - tinnitus - difficulty focusing the eyes/double vision - disorientation -ringing in the ear |
|
|
Progressive symptoms of CNS stimulation from LA OD
|
- lethargy
- unresponsiveness -lack of movement of the extremities -drowsiness and sedated - lack of muscular tone - mild drop in blood pressure, heart rate and respiratory rate |
|
|
What happens to the CVS system with toxic levels of LA?
|
-LA produce direct depression of the myocardium, slow conduction of impulses through the AV node, and prolong the refractory period
|
|
|
What [ ] of LA in the blood give certain S&S of CVS toxicity?
|
>5mcg/ml: moderate to severe myocardial depression
7.5-10 mcg/ml: generalized tonic-clonic seizures >10mcg/ml: severe vasodilation--> ventricular fibrillation--> asystole |
|
|
Calculation to estimate the weight of a child under 10 years old (if you are dumb enough to not have a scale in your office)
|
(Age x 2) + 9= weight in Kg
|
|
|
What is a good rule of thumb for the dosage for blocks in children?
|
- the dose for kids is ~ half the dose used in adults
|
|
|
What is the max dose of lidocaine?
|
7 mg/kg
|
|
|
If a child weighs 15 kg, how many cartridges of lidocaine can you give them?
|
Max= 2.9 cartidges
|
|
|
What is the max dose of mepivacaine?
|
6.6 mg/kg
|
|
|
If a child weighs 15 kg, how many cartridges of Mepivacaine can you give them?
|
MAX=1.8 cartridges
|
|
|
What is the max dose of prilocaine?
|
8 mg/kg
|
|
|
If a child weighs 15 kg, what is the max number of cartridges you can give them?
|
MAX=1.67 cartridges
|
|
|
What is the max dose of articaine?
|
7 mg/kg
|
|
|
If a child weighs 15 kg, what is the max number of cartridges you can give them?
|
max= 1.4 cartridges
|
|
|
What is unique about articaine?
|
- ester-amide hybrid
-Metabolic pathway: amide= primary. Ester= secondary. Biotransformed in both plasma and liver. |
|
|
Where is the most likely place to get post La parasthesia? following which injection?
|
- following anesthesia of the mandibular arch,
- following injection of articaine and prilocaine (both 4%) -tongue most likely to be symptomatic, followed by the lip - |
|
|
Ratio solutions of vasopressors:
|
1:50 000= 20 mcg/mL
1:100 000= 10 mcg/mL 1:200 000= 5 mcg/mL |
|
|
How many mg of lidocaine and mcg of epi does 2.5 cartridges of 2% lidocaine (1:100 000) have?
|
90 mg lidocaine
45 mcg epinephrine |
|
|
Why is bupivacaine's time to onset longer than all other LA?
|
bc it's pKa is higher, there are less neutral molecules in the ratio in tissue's 7.38 pH environment
|
|
|
how many mcg of epi are in 1 cartridge of 2% lidocaine 1:100 000?
|
18 mcg epi / cartridge
|
|
|
how many mg of lidocaine in 1 cartridge of 2% lidocaine?
|
36 mg lidocaine/cartridge
|
|
|
Max dosage of lidocaine
|
7 mg/kg or 13 cartridges
|
|
|
Max dosage of articaine
|
7mg/kg or 7 cartridges
|
|
|
Max dosage of bupivacaine
|
2.0 mg/kg or 10 cartridges
|
|
|
Max dosage of mepivacaine
|
6.6 mg/kg or 11 cartridges (7 if plain)
|
|
|
Max dosage of prilocaine
|
8.0 mg/kg or 8 cartridges
|
|
|
4 reasons that could cause failure of the mandibular block
|
- presence of inflammation
-incorrect needle placement - anatomic variation -fear and anxiety |
|
|
Why might articaine be more successful at freezing with infiltrations?
|
articaine is more lipid soluble than lidocaine
|
|
|
What was found to have the most success for mandibular blocks?
|
IANB with 2% lidocaine with infiltration of 4% articaine
|
|
|
Which injection would you use?
-15 end |
infiltration
|
|
|
Which injection would you use?
impacted 18 |
-PSA/greater palatine
|
|
|
Which injection would you use?
47crown prep |
IANB with long buccal
|
|
|
Which injection would you use?
44MO |
incisive NM
|
|
|
Which injection would you use?
44 exo |
incisive NB with lingual infiltration
|
|
|
Which injection would you use?
41 exo |
-incisive NB and lingual infiltration
- often cross innervation on the central ( 11/21 and 31/41) therefore add a buccal infiltration - alternate: do incisive injection on both sides and a lingual infiltration |
|
|
Which injection would you use?
-root planing and scaling quad 1: |
PSA, ASA, infiltration @ 6 + lingual = GP/ NP
|
|
|
Which injection would you use?
- Flap from 32-35 |
mental block
*don't need pulpal anesthesai, only soft tissue anesthesia |
|
|
Why is the half life of articaine only about 20 minutes?
(compare 1/2 life of lidocaine at 90 minutes) |
articaine contains both an amide, and a ester chain. This ester chain is hydrolyzed by plasma esterases rending the molecule inactive. This allows articaine to have less risk for SYSTEMIC toxicity ( but remember it has greater risk for LOCAL toxicity, manifesting as parasthesias.
|
|
|
If articaine is both an amide and a ester, does it have risks to cause allergy to PABA like other esters?
|
No, does not have any cross reactivity to PABA derivatives.
|
|
|
What if you have a VERY long appointment that outlasts the half lives of LA, and need to administer more that the MAX DOSE?
|
can add 25% of max dose of the LA agent can be added during each subsequent hour of the procedure , provided the patient is totally healthy.
|
|
|
What if you are MIXING 2 different agents? how do you know when you have hit the max dose you can give?
|
- if half the max dose for lidocaine has been administered, it would be safe to administer up to half the max dose for mepivacaine.
|
|
|
How does levonordefrin differ from epinephrine's reactions on the CVS?
|
-Nevonnordefrin closely resembles norepinephrine rather than einephrine and lacks activity at Beta 2
- Epinephrine increases heart rate and systolic pressure but lowers diastolic pressure - In contrast, systemic administration of norepinephrine increases systolic, diastolic and mean arterial pressures, and this triggers a reflex slowing of heart rate |
|
|
So, considering levonordefrin slows heart rate, that means it's safer for 'cardiac' patients right?
|
- consider the undesirable influence on blood pressure. the 1:20 000 levonordefrin [ ] is considered equipotent to 1:100 000 epi [ ] in terms of alpha receptor activity (vasoconstriction).
- equivalent efficacy for constricting vessels, decreasing local hemorrhage, and anesthetic absorption similar |
|
|
Guidelines to follow if using vasopressors in pt medicated with beta blockers
|
- avoid using vasopressors, if reasonable
- if a vasopressor is to be used, record blood pressure and heart rate, then proceed as follows: (a) after the injection of each cartridge, pause 5 minutes and re-assess vital signs before administering any additional LA or (b) infiltrate the entire region to be treated by using a vasopressor to constrict local vessels, then reinject the region with a LA free of vasopressor |
|
|
After give a vasppressor, when would you expect peak serum levels?
|
- peak serum levels of epi are within 5 minutes and decline rapidly due to inactivation by COMT
-generally, the hemodynamic influences of epi are witnessed within minutes of injection, and have completely subsided in 20 mins. |
|
|
What is the only naturally occuring local anesthetic?
|
Cocaine
|
|
|
Characteristics of Nococain
|
- slow onset (10-15min)
- Short duration (5-20min) - Inconsistent anesthesia - tendancy to cause allergies (ester) |
|
|
What concentrations does mepivacaine come in?
|
3% plain
2% with levonordephrin 1:20,000 |
|
|
What concentrations does priolocaine come in?
|
4% plain
4% with 1:200,000 epi |
|
|
What concentrations does bupivicaine come in?
|
0.5% with 1:200,000 epi
|
|
|
What concentrations does articaine come in?
|
4% with 1:100,000 epi
4% with 1:200,000 epi |
|
|
Is articaine superior to lidocaine?
|
It is one of the most popular in Canada, but no best. Just as good as lidocaine.
- increase popularity likely due to the "wine effect" in marketting |
|
|
Chemical structure of esters and amides
|
aromatic ring (lipophilic)
intermediate linkage terminal amide |
|
|
What differentiates and amide from an ester chemically
|
the intermediate linkage
|
|
|
different types of terminal amides
|
tertiary form = lipid soluble
quaternary form = charged and water soluble |
|
|
In what order does sensation diappear and reappear?
|
disappear: touch --> pressure --> pain
reappear: pain --> pressure --> touch |
|
|
Which nerve are anesthetized first?
|
smaller ones (ie C fibers)
|
|
|
Which nerve fibers are anesthetized first?
|
the outer fibers (soft tissue anesthesia)
|
|
|
How much lidocaine is neutral inside cartridge?
|
1% neutral (99% ionized) at pH 4
|
|
|
What is pKa of lidocaine
|
7.8
|
|
|
Given the pH in the extracellular space and nerve membrane is 7.3, would there be more neutral ion present or less compared to lidocaines pKa?
|
pKa 7.8 which is less acidic than 7.3 --> more neutral molecules
20% neutral, 80% ionized |
|
|
What is pH of periaxonal fluid?
|
7
|
|
|
Clinical correlate relating to lipid solubility of anesthetic
|
Onset and Potency (% solution)
|
|
|
Clinical correlate relating to protein binding of anesthetic
|
Duration of action
|
|
|
Clinical correlate relating to dissociation constant (pKa) of anesthetic
|
Time of onset
|
|
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Clinical correlate relating to presence of amide vs ester in anesthetic
|
Clearance and biotransformation
(amide blood breakdown, ester liver breakdown |
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How to convert % solution to mg/ml?
|
move decimal place to the right
ex 2% = 20mg/ml |
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How many mcg/ml is 1:100,000 epi soln?
|
10mcg/ml
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Length of long vs shot needle
|
long: 32mm
short: 20mm |
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What is Dr. Chanpongs advice following a needle breakage?
|
often best leave it in the tissue - more damage will be made trying to remove it than leaving it in there.
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Efficacy and pain difference bw 30 and 25 gauge needles>
|
No difference
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Ingredients found in plain and vasopressor containing cartriges?
|
LA drug
Sodium chloride Distilled water Only in vasopressor containing? - Vasopressor - Citric acid (lowers pH) - Sodium (meta)bisulfite ( antioxidant not a preservative) |
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What is usually most painful: insertion or injection?
|
Injection
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for infiltrations (supraperiosteal).
|
Pulpal: any max tooth
other: buccal tissue and supporting bone Needle: 28S Insert: Height of MB fold Path: // to alveolar bone Target: at or above root apex Volume: 0.6ml (1/3 cartridge) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for PSA.
|
Pulpal: Max 6-8 (72% MB root of 6)
other: buccal tissue and supporting bone Needle: 25L, 27S Insert: MB fold over 7 Path: upward, inward and backward 15º Target: Ptergomax space 16mm inwards (3/4 of short needle, 1/2 of long needle) Volume: 0.9ml (1/2 cartridge) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for MSA nb.
|
Pulpal: Max 4-5 (28% MB root of 6)
other: buccal tissue and supporting bone Needle: 27S Insert: MB fold over 5 Path: // to alveolar bone Target: Above root apex Volume: 0.6ml (1/3 cartridge) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for ASA nb.
|
Pulpal: Max 1-5
other: buccal tissue and supporting bone + anterior tissue on face Needle: 25L (27S) Insert: MB fold over 4 Path: Contact bone Target: Infraorbital foramen (1-2 min pressure) Volume: 0.9ml (1/2 cartridge) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for greater palatine nb.
|
Pulpal: n/a
other: hard palate in posterior Needle: 27S Insert: Palate anterior to greater palatine foramen Path: Contact bone and use pressure anesthesia Target: Greater palatine nerve Volume: 0.45ml (1/4) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for anterior palatine nb.
|
Pulpal: n/a
other: hard palate in anterior Needle: 27S Insert: Lateral to incisive papilla Path: Contact bone and use pressure anesthesia Target: Incisive foramen Volume: 0.45ml (1/4) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for IA nb.
|
Pulpal: Mand 1-8
other: ant buccal tissue, body of mandible, ant 2/3 tongue, lingual tissue Needle: 25L Insert: 3/4 of the way from coronoid notch to raphe Path: Contact bone and withdraw. Approach from opposite side of mouth Target: IAN prior to entering mandibular foramen Volume: 1.5-1.8ml (almost all) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for long buccal nb.
|
Pulpal:n/a
other: post buccal tissue Needle: 25L Insert: MB area distal and buccal to last mand molar Path: contact bone Target: buccal n. passing over border of the ramus Volume: 0.3ml (1/6) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for gow-gates nb.
|
Pulpal: IAN, Lingual n., auriculotemporal n., mylohyoid n., and long buccal (75%)
Needle: 25L Insert: MB area adjacent to max 6, ptn much open wide Path: contact bone, approach from across (canine area) Target: lateral aspect of aneterior portion of condyle (1-2 min keeping mouth open) Volume: 1.5-1.8ml (almost all) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for akinosi-vanosi nb.
|
Pulpal: IAN, lingual n., local buccal n.
other: Needle: 25L Insert: distal to MB fold adjacent to tuberosity Path: // to occlusal plane in max vestibule Target: V3 on lingual aspect of ramus Volume: 1.5-1.8ml (almost all) |
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Describe: anesthetized tissues, ideal needle to use, insertion point, insertion path, target and volume of LA deposited for incisive nb.
|
Pulpal: n/a
other: ant buccal tissue, lower lip and chin Needle: 27S Insert: MB fold at mental foramen Path: advance towards mental foramen Target: mental n as it exits foramen (1-2 min pressure) Volume: 0.6ml (1/3) |
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How much of a nerve do you need to bathe in LA to block it?
|
10mm (3 nodes of ranvier)
|
|
|
What does success of gow gates nb mostly depend on?
|
how wide the ptn can open their mouth
|
|
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What does positive aspiration in gow gates generally indicate?
|
you are not high enough
|
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What is akinosi-vazirani block most useful for?
|
- uncoorperative children
- patients with trismus (mouth can be mostly closed) |
|
|
List examples of ASA II patients
|
- controlled HTN
- mild asthma - smoker - asymtomatic HBV or HCV (kidney) - controlled T2D - controlled hyper/hypothyroid - ADD/ADHD - depression |
|
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List examples of ASA III patients
|
- controlled angina
- aortic steonsis (dependant on grade) - pulmonary stenosis (dependant on grade) - moderate asthma/steroids - ptn on dialysis - controlled T1D |
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|
List examples of ASA IV patietns
|
- uncontrolled angina
- critical aortic steonsis - pulmonary steonsis - severe asthma (eg lives in hospital) - end stage liver / kidney failure - uncontrolled T1D - uncontrolled hyperthyroidism |
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|
ASA category of ptn with 24 to live
|
ASA V
|
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What history could make someone a "cardiac patient"?
|
- HTN
- acute angina - CVA in previous 6 months - congestive heart failure - cardiac dysrythmias - hyperthyroid (graves disease) |
|
|
What physiological effects does epi have on body?
|
- increase HR
- increase stroke volume - increase SYS BP - increased myocardial o2 consumption - cardiac automaticity |
|
|
What is the threshold of epi necessary to cause these physiological changes
|
- 1 cartridge of 1:100K (50-100pg/ml) epi to cause increase HR
- 2 cartridges of 1:100K (75-150pg/ml) epi to cause increased SYS bp - 4 cartridges of 1:100K (150-200pg.ml) to cause increase DYS bp |
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|
Max dose of 1:100K epi in healthy ptn?
|
0.2mg (20ml) or 11 cartridges
|
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Max does of 1:100K epi in ASA III or IV CV patient?
|
0.04mg (4ml) or 2 cartridges
|
|
|
What are some identifiable causes of HTN?
|
- sleep apena
- drug induced - chronic kidney disease - primary aldosteronism - renovascular disease - chronic steroid theraphy - cushings syndrome - coarctation of the aorta - thyroid or parathyroid disease |
|
|
Management of chronic stable angina
|
- treat risk factors agressively esp smoking and hyperlipidemia (goal LDL <2.5)
- sublingual NTG as needed - aspirin 325mg/day (or clopidogrel) - beta blocker and nitrate - CCB for symtom control - if on antiplatelet, tripple therapy and still symtpomtic --> add 2nd class CCB |
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|
If patient is on a nonselective beta blocker, which precautions should be taken?
|
do not give LA cartridge
|
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DDS IHP protocol
|
- vital signs
- stress reduction ( chairside manner, profound LA, sedation) - limit epi to 0.04mg - aspirate several times, injects slowly - use smallest effective dose (ex 1:200K) - never used retraction cord with epi! Consider: - oxygen by nasal cannula - avoiding elective tx within 6mo of an MI (emergency tx in hospital ok after 1 month post MI) |
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|
When is steroid coverage recommended?
|
Major surgery : give steroids if they have been on steroids over past 30 days
OR If the reason they are on steroids is a primary reason |
|
|
What are trigger agents for malignant hyperthermia?
|
- succinylcholine
- inhalation vapor |
|
|
What is bridging therapy?
|
take a ptn off a blood thinner that affects their INR and put them on another that acts as an anticoagulent
|
|
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When not to treat pregnant patietn?
|
avoid 1st trimester
|
|
|
Some recommendation for patient with haemorragic disorders
|
- elevate missing factor to 30%
- aspirate repeatedly - slow injections - infiltractions rather than blocks - intraligamentory or intraosseous - consider referral to hospital |
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|
Half lives of lido, mepivicaine, prilocaine
|
90minutes
|
|
|
Why may LAs with epi be more painful on injection?
|
plain ~ pH 6.5
vaso ~ pH 3.5 (if does not have epi, does not need low pH) |
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|
The lower the pKa, the _________ the onset of action.
|
faster
pKa<pH --> less neutral molecules, more charged --> more binding and blockage of Na channels |
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|
How does potency relate of lipid solubility and %soln?
|
the more lipid soluble an LA, the greater its potency
the higher the %, the lower the lipid solubility and thus the less potent the LA is |
|
|
Which LAs, in the % generally sold, are the most/least lipid soluble
|
procaine - lowest
bupivacaine - highest |
|
|
How do ionized molecules act to stop nerve impulse?
|
- block entry of NA into interior of nerve when simulation occurs --> preventing propagation of nerve impulse
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|
|
Where should you redeliver LA if more needed?
|
Higher from previous point
|
|
|
Relationship bw duration of action and protein binding
|
increased protein binding, increases duration of anesthesia
|
|
|
What causes a shorter duration of action?
|
- diffusion away from nerve (blood vessels, and lymphatics)
- redistribution of LA |
|
|
Time of Peak blood levels of plain LA?
|
5-10min
|
|
|
Time of peak blood levels of LA+epi
|
20-30min
|
|
|
What are the breakdown products of esters and amides?
|
all esters --> PABA
amides --> breakdown products differ between types |
|
|
List short acting LAs and time of duration
|
~30min
- mepivacaine plain - prilocaine plain (infiltration) |
|
|
List long acting LAs and time of duraction
|
>90min
- bupivacaine w/ epi |
|
|
Intermediate acting and time of duration
|
- lidocaine w/ epi
- mepivacaine w/ levo - prilocaine (nb) - prilocaine w/ epi - articaine w/ epi |
|
|
does concentration affect duration of action?
|
no, it affects potency !
|
|
|
Describe the normal distribution curve in relation to individual response (duration of action) to lidocaine
|
70% respond appropriately (60min pulpal)
15% hyporespond (<60min pulpal) 15% hyperrespond (>60min pulpal) |
|
|
Factors to consider affecting duration of action
|
1. individual variation
2. accuracy of deposition 3. status of tissue at site (vascularity and pH) 4. anatomical variation 5. type of injection (block > infiltration) |
|
|
Average duration of action for lidocaine
|
pulpal: 60min (infiltration); 85min (IANB)
soft tissue: 170-190 |
|
|
Max recommended dose for lidocaine HCl
|
7mg/kg
absolute max = 500mg |
|
|
Max recommended dose for 3% mepivacaine HCl plain
|
6.6mg/kg
absolute max = 400mg |
|
|
Max recommended dose for 2% mepivacaine HCl with vasoconstrictor
|
6.6mg/kg
absolute max= 400mg |
|
|
Duration of anesthesia for mepivacaine with vaso
|
pulpal: 50min (infiltration); 75min (IANB)
soft tissues: 130-185 |
|
|
Levonordephrin vs epi
|
- similar structure
- does not increase HR - does increase BP - similar strength to 1:100K epi - may have exaggerate response with TCA, SNRI, Duloxetine |
|
|
Max recommended dose for prilocaine
|
8mg/kg
absolute max = 500mg |
|
|
duration of anesthesia for 4% plain prilocaine and with vasoconstrictor
|
pulpal: 20min (infiltration); 55min (nb)
soft tissue: 105-190min (inf - nb) with vasoconstrictor: pulpal: 40min (inf); 60min (IANB) soft tissue: 140-220 |
|
|
Max recommeneded dose for bupivacaine
|
2mg/kg
absolute max = 90mg |
|
|
duration of anesthesia for bupivacaine
|
pulpal: 20-40mim (inf) or 240min (IANB)
soft tissue: 340-440min !! (remember bupivicaine has a high degree of protein binding) |
|
|
When to avoid long acting anesthetics?
|
children and special needs ptns
|
|
|
Max recommended dose for articaine
|
7mg/kg
absolute max = 500mg |
|
|
Is articaine an ester or an amide?
|
ester-amide hybrid
- primary amide linkage - secondary ester linkage |
|
|
Duration of anesthesia for articaine
|
pulpal: 60min (inf); 90min (IANB)
soft tissue: 190-230min |
|
|
What is the relationship between half life of a drug and its clinical duration of action
|
shorter halflife = longer duration of action ?
|
|
|
Which LAs are most likely to case parasthesia?
|
1. articaine
2. prilocaine |
|
|
Rank lido, mepi, mepi plain, prilo, prilo plain, arti and bupi in order based on protein binding
|
(highest)
bupi articaine lido prilocaine = mepi |
|
|
Rank lido, mepi, mepi plain, prilo, prilo plain, arti and bupi in order based on onset
|
(slow)
bupi lido, arti, prilo, mepi (fast) |
|
|
Rank lido, mepi, mepi plain, prilo, prilo plain, arti and bupi in order based on duration of pulpal anesthesia (inf)
|
(longest)
articaine = lido mepi prilo = bupi mepi plain prilo plain |
|
|
Rank lido, mepi, mepi plain, prilo, prilo plain, arti and bupi in order based on duration of pulpal anesthesia (IANB)
|
(longest)
bupi>>> arti lido mepi prilo prilo plain mepi plain |
|
|
Vasoconstrictors should be included in all LA soln unless there is compelling reason for their exclusion such as..
|
1. short duration of action desired
2. medical contraindication |
|
|
Absolute contraindication for LA w/ vasoconstrictors in CV patients
|
Unstable angina
Recent myocardial infarction Recent coronary artery bypass surgery Refractory dysrhythmias Untreated / uncontrolled severe high blood pressure Untreated / uncontrolled congestive heart failure |
|
|
Absolute contraindication for LA w/ vasoconstrictors in ptns with Hyperthyroidism, diabetes, sulfite sensitivity, cortico-dependent asthma, and pheochromocytoma.
|
Uncontrolled hyperthyroidism
Sulfite-sensitivity Pheochromocytoma |
|
|
Contraindications to vasoconstrictors in dentistry: Pharmacologic interactions
|
- Tricyclic antidepressants and levonordephrin
- Monoamine oxidase inhibitors breaks down - Cocaine abuser |
|
|
Can patient be allergic to local anesthetic?
|
Yes.
allergies 1-10% of US pop - allergy to breakdown product of esters PABA - allergy to "other" ingredients like: sodium metabisulfite (used to slow down oxidation of vasopressor) |
|
|
Presentation of a psychogenic reaction LA
|
Anxiety induced:
- syncope - hyperventllation - nausea - vomitting - alteration in HR and BP |
|
|
Presentation of allergic reaction to LA
|
- pruritis
- urticaria - angioedema - difficulty breathing - shock (within another 1-2min) |
|
|
Are LA generally safe to use?
|
yes
|
|
|
how much LA is needed to anesthetize all 20 primary teeth at one time?
|
you would never do this!
(but technically would take <2 cartriges) |
|
|
what drug would you used to anesthetize child?
|
LA with epi
|
|
|
Is a cooperative or non-cooperative child more at risk in the hands of a young inexperienced dentist?
|
cooperative child because they will allow you to give injections all at once
|
|
|
When are peak blood levels reached following intraoral admin?
|
10 minutes after
|
|
|
What are some strategies to reduce chance of adverse effects in LA admin to children?
|
- nerve block preferred to infiltration ( incicive nb, ASA nb)
- administer appropriate volumes - select appropriate drug for procedure (should contain vasopressor) |
|
|
CNS toxicity - physiologic effects
|
- biphasic (stimulation/depression"
- depression of cerebral inhibitory centers - unopposed facilitatory neurons causing random stimulatory firing of the neurons in the brain producing tonic$clonic seizures - Respiratory arrest is not uncommon - incr oxygen consumption of the tonic muscles - Progression to hypoxia, cyanosis, and cardiac arrest |
|
|
What CNS effects would be expected to occur when LA levels are between 0.05 and 4mcg/ml?
|
anticonvusant and sedative effects
|
|
|
What CNS effects would be expected to occur when LA levels are between 4-7mcg/ml?
|
mild CNS stimulatory signs
|
|
|
What CNS effects would be expected to occur when LA levels are between 7.5-10mcg/ml?
|
generalized tonic-clonic seizures
|
|
|
MILD Signs and symptoms of CNS stimulation
|
- talkativeness
- slurred speech - apprehension - localized muscle twtiching - lightheadedness - circumoral numbness or numbness of tongue - tinnitus - difficulty focusing the eyes/double vision - disorientation |
|
|
Progressive symptoms of CNS stimulation
|
- lethargy
- unresponsiveness - lack of movemetn of the extremities - drowsiness and sedated - lack of muscular tone - mild drop in BP, HR and RR |
|
|
What cardio effects would be expected to occur when LA levels are between >10mcg/ml?
|
severe vasodilation --> ventricular fibrillation --> asystole
|
|
|
What cardio effects would be expected to occur when LA levels are between 7.5-10mcg/ml?
|
generealized tonic-clonic seizures
|
|
|
Cardio toxicitiy by LA - physiological effects
|
LA produce a direct depression of the myocardium, slow conduction of impulses through the AV node, and prolong the refractory period
> 5 mcg/ml, moderate to severe myocardial depression Up to 10 mcg/ml, bradycardia, negative inotropic actions, and peripheral vasodilation |
|
|
Easy formula for calculating max dose for children?
|
(age x 2) + 9 = weight in kg
max allowable dose (mg/kg) x weight in kg |
|
|
Max allowable dose in mg/g for lido, mepi, prilo and arti in children?
|
lido and arti : 7mg/kg
mepi : 6.6mg/kg prilo: 8mg/kg |
|
|
Max # cartriges for lido, bupi, mepi, prilo and arti in children?
|
0.5% bupi: 3.3
2% lido: 2.9 3% mepi: 1.8 4% prilo: 1.67 4% arti: 1.4 |
|
|
Features of facial nerve palsy due to IANB
|
• generalized weakness of the ipsilateral side of the face • inability to close the eyelids
• obliteration of the nasolabial fold • drooping of the corner of the mouth • deviation of the mouth to the unaffected side |
|
|
How could a PSA nerve block lead to facial nerve palsy?
|
• Possibly caused by a retrograde injection into the PSA artery --> middle meningeal artery--> petrosal artery branches --> facial nerve
|
|
|
How could PSA nerve block lead to temp blindness? Whic other nerve block could this happen?
|
due to a large quantity of local anesthetic under great pressure diffusing through the inferior orbital fissure and coming into contact with the optic nerve.
Also: IANB, V2NB |
|
|
Features of abducens nerve palsy resulting from PSAnb
|
- double vision
- limitation of abduction LA reaches the abducens nerve within the cavernous sinus, arriving via the infratemporal fossa and the pterygoid plexus and its connecting emissary veins passing through the foramen ovale and lacerum. |
|
|
In most individuals, even those with
heart disease, the CVS effects of conventional doses of adrenergic vasopressors are of little practical concern. What are the exceptions? |
- Accidental intravascular injection,
- Unusual patient sensitivity, - Unanticipated drug-drug interactions, - Excessive doses |
|
|
Describe accessory innervatoin of mandible by mylohyoid nerve?
|
- Mylohyoid nerve enter the mandible through “retromental foramina” through lingual aspect of the mandible
- Carries sensation anywhere from 1st molar to incisors - Branches from IAN anywhere from 5 to 23 mm - Mylohyoid innervation of mandibular teeth 60% |
|
|
Describe accessory innervatoin of mandible by branches of V3?
|
- Branches of V3 enter
mandible high and anterior to the mandibular foramen and innervate 2nd and 3rd molars - Branches that enter the mandible in the retromolar fossa area and innervate the 1st and / or 3rd molar |
|
|
What is OraVerse? Is it worth spending money on?
|
- Reverses the freezing by causing vasodilation to increase (return to normal sensation in 1/2 the time)
- Might be useful for patient with special needs or severe dementia. - Big drawback is $$, esp for something that doesnt work instantly. - Not availible in Canada. - Effects are not instant like LA - Reduced the length of time the patient is frozen Bottom line: doesn't work fast enough to make it worth it |
|
|
How many mg per cartridge of 2% lido?
|
36mg
|
|
|
How many mg per cartridge of 3% mepivacaine?
|
54mg
|
|
|
How many mg per cartridge of 2% mepivacaine?
|
36mg
|
|
|
How many mg per cartridge of 4% prilocaine?
|
72mg
|
|
|
How many mg per cartridge of 0.5% bupivacaine?
|
9mg
|
|
|
How many mg per cartridge of 4% articaine?
|
72mg
|
|
|
Is levonordephrin (mepivacaine 2%) safer for cardia patients?
|
no.
(α > β – still increases BP), 1:20K levo equal to 1:100 000 epi |
|
|
beta blockers cause..
|
decrease force and rate of heart contraction (Beta 1)
and vasoconstriction of skeletal m. arteries + bronchodilation (beta 2) |
|
|
drugs that block alpha receptors cause...
|
decrease arterial smooth m. contraction
(nb when non-selective beta blocker present, alpha receptors will be uninhibited and epi can bind to them instead causing increase arterial smooth m. contraction --> increase BP) |
