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192 Cards in this Set
- Front
- Back
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What color is the 27 gauge needle?
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yellow
*red is 25 gauge and blue is 30 gauge |
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What length needle would we use for an IAN block?
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the long needle (32) bc the average length is 25 mm.
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where do needles always break?
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the HUB
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why is a large gauge needle preferred?
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less deflection
easier aspiration less chance of breakage |
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what is the fluid standard in a cartridge?
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1.8 ml
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what is sodium bisulphite used for ?
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its an antioxidant in a vasopressor containing local anasthetic
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what is sodium chloride used for?
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to keep solution isotonic and bc its a powder
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What injection is best for 1 tooth?
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Supraperiosteal (.6 ml or 1/3 cartridge)
-aim for apex of tooth |
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What do you expect to be frozen from supraperiosteal?
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buccal soft tissue and the supporting bone.
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You want to freeze the maxillary molars on the buccal for some scaling. What block will you use?
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The PSA (.9 ml or 1/2 cartridge)
-aim for mucobuccal fold over 2nd molar upward inward and backward -16mm or 1/2 long needle or 3/4 short |
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what is the target for the PSA?
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the pterygomaxillary space
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If you were to use an ASA block, what teeth will be frozen?
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-the anterior teeth and the premolars on that side.
-(.9 ml or 1/2 cartridge) -apply pressure!! |
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if I want teeth blocked posterior to premolars on the left and on the palatal side ...what block?
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the left greater palatine
-.45 ml or 1/4 cartidge |
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If I wanted the mesial of right 1st premolar to mesial of left 1st premolar frozen what block?
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the nasopalatine
-about the size of your rubber stopper |
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First anathetic for dentistry given?
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1844-1846
NITROUS OXIDE -Wells/Cooley/Colton |
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First nerve block?
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IAN block with COCAINE (1886)
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is Novocaine an ester or amide?
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ester (so it has the allergy problem)
-short duration |
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Mepivacaine
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3 % plain
2% with levonordefrin 1:20 000 |
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Prilocaine
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4% plain
4% with epinephrine 1:200 000 |
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Bupivacaine
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.5% with epinephrine 1:200 000
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Articaine
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4% with 1:100 000 epinephrine
4% with 1:200 000 epinephrine |
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Which fibers are hit first?
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C fibers bc smallest.
-hit first but also lose freezing first |
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what is the pKa?
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the pH of the drug at which 50% is ionized
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What molecules pass through the membrane?
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neutral molecules
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what molecules block nerve conduction?
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ionized
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What causes the termination of action of local anasthetic?
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redistribution
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what changes with vascularity at the injection site?
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more vascularized means we need to be more concerned with overdose and a shorter duration of action
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If an anasthetic has increased protein binding what does that mean?
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increased duration of action
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what does lipid solubility mean as a property?
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Onset an potency..penetration
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Dissociation constant? PKA
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time of onset.
- A PKA closer to physiological @7 will have more neutral molecules to pass through the membrane and therefore a faster onset. |
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Amide is broken down?
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in liver
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Ester is broken down?
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In the blood
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Name the 5 Amides
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1. Lidocaine
2. Mepivacaine 3. Bupivacaine 4. Prilocaine 5. Articaine |
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Primary rationale of adding a vasoconstrictor?
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increase duration of effect. Decrease distribution
-secondary rationale is to decrease systemic toxicity |
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How many ug of epi is in 1 cartridge? )1:100 000
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18 ug
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How much lidocaine in 2% cartridge?
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20mg x 1.8 =36 mg/cartridge
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You use 2.5 cartridges of 2% lidocaine. How much epi and how much lido?
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epi= 18x2.5-->45ug
lido=36x2.5-->90mg |
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what are the 4 mandibular blocks we learned?
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IAN
Gow Gates Akinosi Vaziani incisive |
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If I want to block all mandibular teeth to the midline, I would use>?
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IAN
-1.5ml -3/4 of a long needle |
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where is the insertion for buccal nerve block?
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mucus membrane distal and buccal to last mandibular molar
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how many ml for buccal nerve block?
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.30 ml
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Which injection for a px with trismus?
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Akinosi Vazirani
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where do you insert for the incisive nerve block?
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MB fold at or anterior to mental foramen
-.6 or 1/3 cartridge -pressure just like ASA! |
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ASA class II
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"mild systemic disease"defines most patients, even if they are just taking an antidepressant.
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controlled type I diabetes
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ASA III
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1:200 000 means how many ug/cartridge?
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9ug epi
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1:50 000 means how many ug/cartridge?
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36ug epi
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The maximum dose of epi for px with heart disease?
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200 ug so no more than 11 cartridges of 1:100 000 (18 ug/cartridge) or .2 mg
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what is the maximum dose of epi for px with significant ASA III or IV heart disease?
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40 ug so no more than 2 cartridges of 1:100 000 (18ug)
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stage 1 hypertension
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140-159 (90-99)
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should u use retraction cord with epi?
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NO PLEASE NO!-THOSE SUCKERS ARE POACHED WITH EPI...you will easily exceed the limits
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MI
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wait 6 weeks and consider doing endo. No full mouth clearance or crazy things until 6 months
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which drugs cause malignant hypothermia?
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succinylcholine
inhalation vapor (iso/deso/sevoflurane) |
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Hemmoragic disorders
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CONSULT
-dont take of blood thinners. You can control a little extra bleeding . -the hospital is incharge of bridging and changing the blood thinners. |
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Why do you have to be careful giving LA with epi to a person who is on nonselective beta blockers?
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With non selective beta blockers, both the beta type receptors are antagonized, so the epi acts primarily on the alpha receptors. The epi will cause a spike in blood pressure and vasoconstriction.
*This doesn't happen with selective beta blockers bc epi can then act on a beta and alpha receptor. |
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How should we limit epi in a px with dysrhythmia?
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.04mg
*never use retraction cord with epi |
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How many cartridges of 1:50 000 could you give a cardiac patient
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(18ugx2 =36 ug)
40ug is the maximum. So 1 cartridge |
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how many cartridges of 1: 200 000 could you give to a cardiac patient?
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(18 ug/2 = 9 ug)
40ug is the maximum. So 4 cartridges. |
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Neurologic complications can be divided into ?
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1. those that arise as a direct result from procedure itself (IAN, PSA)
2. those due to toxicity of agents used |
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Name some complications that can arise from a IAN block
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facial nerve palsy
Transient Amaurosis Total body Hemiparesis Post injection paraesthesia Horners syndrome Transient paralysis of combinations of cranial nerves Sudden unilateral deafness |
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Name some complications arising from PSA block
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abducens nerve pulsy
Temporary blindness |
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What is the most common complication following a IAN?
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facial nerve pulsy
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What signs do you look for in a px with facial nerve pulsy?
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-generalized weakness of ipsilateral face
-inability to close eyelids -obliteration of nasolabial fold -drooping of the corner of the mouth -deviation of the mouth to the unaffected side |
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what does an upper motor lesion spare?
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the muscles of the forehead
-this area receives dual innervation from the cerebral hemispheres and the fibers then cross over |
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What does a peripheral nerve lesion affect?
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all muscles of the face
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What causes Horners syndrome?
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Penetration of the LA through the lateral pharyngeal and prevertebral spaces, causing blockade of the stellate ganglion
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signs of HOrners
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-same side flushing of the face
-ptosis of eyelid -vasodilation of conjunctiva -pupillary constriction -occasionally a rash over same side shoulder and arm |
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Transient paralysis is most likely caused by what injection?
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Gow Gates bc it goes in deposited in superior position
-LA gains access to cavernous sinus from venous injection -paralysis of combined nerves VI, III, IV -dilated pupils and ptosis of eyelid |
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A patient complains of double vision, limitation of abduction of ipsilateral eye and parasthesia of lateral side of the upper and lower eyelids. what block did this and what is the dx?
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abducens nerve pulsy
PSA |
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benzodiazepine antagonist
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FLumazenil
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toxic buildup of LA is important for what two populations of patients?
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Liver failure (amides)
Renal failure |
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LAs interrupt nerve conduction by inhibiting influx of what ions?
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sodium ions
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What are the 3 components of a LA molecule?
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a)lipophilic aromatic ring
b)intermediate ester or amide chain c)terminal amine |
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What property correlates with potency?
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lipid solubility
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Why is bupivicaine prepared at a .5% (5mg/ml) solution unlike lidocaine 2%? (20mg/ml)
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it is more lipid soluble (more potent)
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For the LA base to be stable in solution , it is formulated as a ?
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hydrochloride salt
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The pKA of all LAs is greater than 7.4, therefore a greater proportion of the molecule exists as?
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the quaternary water soluble state that does not penetrate the neuron.
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The lower the pKA the more effective penetration of the neuron, therefore would you rather use bupivacaine or mepivacaine when you experience difficulty anethetizing inflamed tissues?
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mepivacaine (7.6)
*bupivacaine is 8.1so least effective |
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what property predicts the duration the LA will sustain its neural blockade?
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protein binding.
*bupivicaine is longest acting and has greatest protein binding |
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Characteristics and clinical correlates.
1.lipid solubility 2.dissociation constant 3.chemical linkage 4.protein binding |
1. potency- (lipid solubility)
2. time of onset- (lower pkA is faster onset) 3. metabolism 4. duration |
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what is the principal life threatening consequence of local aneasthesia overdose?
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convulsive seizures
-LAs must be respected as central nervous system depressants and potentiate any respiratory depression associated with sedatives and opioids |
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WHat is a safe practice in dosage?
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overestimate! example, consider each cartridge as 2ml instead of 1.8.
-3% mepivucaine contains 30 mg/ml -(30mg/ml x 2)-->60mg of mupivacaine. |
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consider the _____ not the ____ administered!
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dose not volume.
(20 ml of 3% is same as 30 ml of 2%) |
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in cases of infection and acute inflammation, it is best not to use what injection technique on the maxilla? What 3 options do you have?
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-do not use supraperiostial, instead use 3 alternatives
-ASA -PSA -maxillary |
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the maxillary nerve exits the cranium through?
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foramun rotundrum
-reaches pterygopalatine fossa and gives off several branches. |
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3 branches of maxillary nerve in the pterygopalatine fossa?
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zygomatic
pterygopalatine posterior superior alveolar |
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the PSA innervates the last 3 molars in the maxillary arch. What is the possible exception?
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the MB of the 6
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the maxillary nerve trunk becomes what nerve as it crosses the inferior orbital fissure?
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infraorbital nerve
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What does the infraorbital nerve give off that we dentists like to block?
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ASA! this supplies :
-incisors, canine and often premolars -facial ginigva -floor of nasal cavity and antrums |
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Why does the eyelid get blocked and sensory of the nose/lip when we do ASA then?
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bc the infraorbital nerve has other branches that get blocked when we apply pressure the the infraorbital foramen. These include branches to the lower eyelid and sensory to the side of the nose and the lip.
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Which drug has the longest onset?
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bupivacaine (6-10 mins)
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what preparations does lidocaine come in?
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plain 2%
1:50 000 1:100 000 |
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What preparations does mepivacaine come in?
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plain 3%
2% with levo 1:20 000 2% with Epi 1:100 000 |
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what preparations does prilocaine come in?
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4% plain
4% w epi 1:200 000 |
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wat preparations doe bupivacaine come in?
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.5% w epi 1:200 000
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wat preparations does articaine come in?
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4% w 1:100 000epi
4% w 1:200 000epi |
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max dose of 2% lidocaine?
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7mg/kg or
500 mg (13 cartridges) |
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max dose of 3% mepivacaine?
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6.6 mg/kg or
400 mg (7 cartridges plain) |
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max dose of 4% prilocaine?
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8 mg/kg or
400 mg (6 cartridges) *this is conservative |
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Max dose of .5% bupivacaine?
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2.0 mg /kg or
90 mg (10 cartridges) |
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Max dose of 4% articaine?
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7 mg/kg or
500 mg (7 cartridges) |
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which LA has the pKA most optimal for a patient with infection and why?
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Mepivacaine. Bc its pKa is the lowest (7.6), therefore in a very acidic environment in infection, it will have more molecules penetrating the membranes and better success. The other drugs have much higher pKAs.
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what LA is associated with permanent parasthesia?
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Articaine bc 4% solution.
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condition that contraindicates use of prilocaine
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hereditary methemoglobinemia
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If LA is needed before medical clearance of a supposed alelrgy, which 2 drugs are safest?
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plain privacaine
prilocaine |
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What accounts for the greater lipid solubility of Articaine when compared with lidocaine?
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thiophene ring instead of aromatic ring
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What is a benefit of Articaine?
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half life of only 20 mins so lowers systemic toxicity
*this is tempered by numerous cases of parasthesia after IAN blocks *therefore it is recommended to restrict the use to infiltration and save nerve blocks for failed attempts with other drugs |
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when using multiple agents, guidelines for maximum dose should be considered?
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additive
*ex. if you administer 1/2 the max dose for lidocaine (250mg), then you can administer up to half the max dose for mepivacaine (275mg) |
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If one accepts the fact that a cartridge is 2ml, then it follows that a 1:100 000 solution (10 ug/ml) is 20 ug of epinephrine. How can you quickly convert for a 1:200 000 and 1:50 000 solution?
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a) halve it for 1:200 000 ...so 10ug
b) double it for 1:50 000...so 40ug |
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why has levonodorforin been suggested for an alternative to epi when treating CVD?
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it lacks activity at Beta2 receptors and triggers a reflex slowing of heart or does not increase heart rate
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epi and levo are metabolized by which enzyme? what is the significance?
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catecholomethyltransferase
*this is significant bc px treated with MO inhibitors (anti depressants), are not affected. *be cautious with TCA drugs bc of the tendency for arrythmias with these drugs. Any additive sympathomimetic action should be avoided |
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patients taking nonselective betablockers have...?
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heightened sensitivity to the systemic affects of vasopressors.
*stroke and cardiac arrest bc of increase in BP then a reflex slowing of HR |
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2guidelines for LA in patients taking beta blockers
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1)avoid the use of vasopressors if reasonable
2)if a vasopressor is used, record BP and heart rate. After the injection of each cartridge wait 5 mins and reassess vital signs. OR infiltrate the entire region treated with a cartridge to constrict bvs then reinject with a PLAIN local. |
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significant cardiac disease means 40ug dose of epi is the limit. How many cartidges of 1:100 000 is this?
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2! (each cartridge has 20ug)
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Prilocaine is metabolized?
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kidneys and plasma and liver
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does an allergy to one amide rule out use of the rest?
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no
*but in esters it does! (breakdown product the same) |
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what should you avoid when a px is allergic to sulfites?
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vasoconstrictor bc metabisulfite is added as an antioxidant whenever vasoconstrictor is present
*no cross allergy with sulfa (antibacterials) |
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one cartridge of 1:20 000 levo is how many ug?
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90ug
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what LA is avoided in children?
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bupivacaine bc its long lasting
*chew off lip *also for disabled kids |
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what does the pterygomandibular space contain that we dentists want to anasthesize?
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the IAN and the lingual nerve
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what muscle is important to miss when inserting the needle for a Gow Gates block?
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the temporalis. It inserts into the coronoid process. So palpate it before you insert the needle.
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what are the nerves anasthetized by the Gow Gates block?
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-IAN
-lingual -mylohyoid -auriculotemporal -buccal |
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Do u need to perform a buccal nerve bock with Gates block?
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No , this is unlike the IAN. This is bc u are already blocking the buccal nerve.
*same for AKinosi |
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Top 2 drugs correlated with parasthesia and what nerve?
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4% articaine and prilocaine. lingual nerve
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most of the time, a +aspiration is in a ...
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VEIN
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What are the absolute contraindications for vasoconstrictors in cardiovascular diseases?
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-unstable angina
-recent myocardial infarction -recent coronary artery bypass surgery -refractory dysrhythmias -untreated/uncontrolled high BP -untreated/uncontrolled congestive heart failure |
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What constitutes unstable angina?
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at rest or change in frequency
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A patients has uncontrolled hyperthyroidism, should you use vasoconstrictors?
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NO, this is a contraindication
also: -sulfite sensitivity (not sulfa) -pheochromacytoma (tumor on adrenal glands) |
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Does plain local have sulfites?
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No! But Amides with vasoconstrictors do
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Your px is a recent cocaine user. What is your worry?
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stroke with LA block.
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So what are the 3 relative contraindications to vasoconstrictors in terms of drug interactions?
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-TCAs (levo)
-Cocaine |
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what happens with TCAs and vasoconstrictors?
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hugely elevated BP response.
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Is it the volume or concentration that matters most in terms of hemostasis need?
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the volume! its better to use a bigger volume of 1/200 000 than a few drops of 1/50 000
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allergenic component of esters?
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PABA (breakdown of all esters)
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When a px is allergic to "LA", they are commonly allergic to the ingredients in the cartridge. Therefore , wat compromises a vasopressor containing LA?
|
LA drug
vasopresser sodium metbisulfite**(antioxidant) sodium chloride citric acid distilled water |
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What comprises a cartridge of plain LA?
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LA drug
sodium chloride** distilled water |
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does the BP go up or down in anaphylactic shock?
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down
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A treating dentist administered 5 cartridges (1.8ml) of mepivacaine 3%. A total of 9.0 ml. How much local did he give?
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3x18=54
54x5=270mg! |
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Is 270 mg of mepivacaine ok for a 17 kg child?
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17x 6.6= 119 mg
NO!!. |
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To obtaine full mouth anasthesia in the primary dentition fewer than ____ cartridges of LA need be administered.
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2
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The most common cause of cardiac arrest in healthy children is ?
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airway obstruction or apnea
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What are 3 things we can look for in terms of mild signs of CNS stimulation after local?
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Tinnitus (ringing in ears)
difficulty focusing the eyes/double vision disorientation |
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What is a quick way to estimate max dose for children <10 yrs?
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(age x2)+9
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so what weight would u predict for a 3 yrs old?
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(3x2)+9=15 kg
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so for this px how many cartridges of 2% lidocaine can u give?
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7mg/kg x 15 kg= 105 mg max dose
105/(2x18)=2.9 cartridges |
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for a 30 kg patient, what would the max cartridges be for 3% mepivacaine?
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6.6mg/kg x 30kg=198 mg max dose
190/(3x18)=3.5 cartridges |
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For a 15 kg patient, what would the max cartridges be for 4%Prilocaine?
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8mg/kg x 15kg=120 mg
120/(4x18)=1.6 Cartridges |
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For a 30kg patient, what would the max cartridges be for 4% articaine?
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7mg/kg x 30kg=210 mg
210/(4x18)=2.91 cartridges |
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Can you use more or less cartridges for 2% lido vs 4% articaine for a given patient?
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You can use 1/2 the number of cartridges for articaine as you can for lidocaine.
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max dose of 2% lidocaine for a 3 yr old kid?
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2.9 cartridges
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max dose of 3% Mepivacaine for a 3 yr old?
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1.8 cartridges
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Max dose of .5 % bupivacaine for 3yr old?
|
3.3 cartridges
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Max dose of 4% prilocaine for 3 yr old?
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1.67 cartridges
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Max dose of 4% articaine for 3 yr old?
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1.4 cartridges
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most LA complications happens when?
|
5 - 10 mins after
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accessory innervation of mandible
|
mylohyoid nerve
branches of V3 |
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Is it the technique or the drug?
|
the TECHNIQUE
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4 reasons for mandibular block failure?
|
1. presence of inflammation
2. incorrect needle placement 3. anatomic variation 4. fear and anxiety |
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What teeth do possible branches of V3 innervate?
|
2nd and 3rd mandibular molars
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If you give an IAN with lidcaine and the patient still feels it, what can you do next?
|
Articaine for buccal infiltration. With infiltration we are not concerned about parasthesisa
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If you were to exo an impacted 18, what techniques would u use?
|
PSA
greater palatine |
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47 crown prep requires what injections?
|
IAN and long buccal
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44 MO resto?
|
incisive NB
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45 exo?
|
incisive NB and lingual infiltration
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41 exo?
|
inicisive NB +lingual and buccal infiltration
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root planing and scaling in quad 1?
|
PSA , ASA, greater palatine, nasopalatine.
*may need to do local infiltration MB cusp of 6 |
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Termination of action of LAs is due to?
|
REDISTRIBUTION
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What is the half life of lidocaine, mepivacaine and prilocaine?
|
90 mins
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what is the shelf life of plain LA?
|
36 months-thats double LA with vaso (18)
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the lower the pKA value, ...
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the faster the onset of anasthesia!
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The more lipid soluble an LA?
|
the more potent!!
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The greater the protein binding...
|
the longer the duration!
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blood level of LA increases as...
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drug is absorbed and redistributed
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peak blood level with epi is?
|
20-30 mins as opposed to without epi (5-10 mins)
|
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short acting amides
|
mepivacaine3%
prilocaine4% (infiltration) |
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long acting amides
|
bupivacaine .5%
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intermediate acting amides
|
lidocaine 2%
mepivacaine 2% priocaine 4% articaine 4% |
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MRD lidocaine 2%
|
500 mg
7mg/kg |
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MRD 3%mepivacaine
|
400mg
6.6 mg/kg |
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Levonordefrin drug interactions?
|
TCA
SNRI * you get an exaggerated response! (increase BP) |
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MRD prilocaine 4%?
|
500 mg
8 mg/kg |
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MRD .5% Bupivacaine?
|
90 mg
2 mg/kg |
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Articaine 4% MRD?
|
500mg
7 mg/kg |
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articaine is biotransformed both in...
|
plasma and liver!
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supraperiosteal injection
|
you must freeze lingual side too
1/3 cartridge (.6ml) |
|
|
PSA
|
you must freeze lingual side too
1/2 to full cartridge needle inserted above maxillary 2nd molar 16mm (1/2 long needle) |
|
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ASA
|
you must freeze lingual side too
1/2 to full cartridge needle inserted in mucobuccal fold above 1st premolar 16 mm (1/2 long needle) http://www.youtube.com/watch?v=_bGxcnufOB0 |
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Greater palatine
|
maintain pressure with q tip
1/4 cartridge (.45 ml) needle inserted anterior to greater palatine foramen http://www.youtube.com/watch?v=CYZ_OT-362A |
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nasopalatine
|
maintain pressure with q tip
volume of rubber stopper needle inserted lateral to incisive papilla http://www.youtube.com/watch?v=5DcNT_jH10A |
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which maxillary injections require half a cartridge?
|
PSA and ASA
|
|
|
which max injections require 1/3 cartridge?
|
supraperiosteal
|
|
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which max injections require 1/4 cartridge orless?
|
nasopalatine
greater palatine |
