Local Anaesthetic Flashcards
How do we prepare the syringe for LA administration
- Check the expiry date and batch number
- Clear rubber bung goes on (the flared part goes on first)
- Put the cartridge into the needle (gold bit goes in first)
- Bring the anchor all the way up and attach it to the syringe, looking for a single click
- Pull back the casing for a single click
What length is a yellow needle
35mm
What length is a blue needle
25mm
How do you administer an IDB
- Hold the ramus and coronoid process
- Stretch the tissues and look for the raphe
- Come across from the premolars on the other side
- Inject 6-10mm above the last standing molar and to the left of the raphe
- Advance until you hit bone then retract slightly (aspirate) and inject
- After injecting about ⅔ then retract about a cm and inject the rest to catch lingual nerve
What are the two types of LA
amide
ester
What are the 3 types of amide LA that are used through out the dental school
lidocaine
prilocaine
articaine
What is the concentration of lidocaine in the cartridge
2.2ml lidocaine 2% + adrenaline 1:80000
What is the concentration of prilocaine in the cartridge
3% with or without felypressin
What is the concentration of articaine in the cartridge
- articaine 4% with adrenaline
Where is lidocaine metabolised
liver
by enzymes
Where is prilocaine metabolised
liver + kidney
Where is articaine metabolised
serum
by plasma cholinesterases
Where are plasma cholinesterases produced
liver
note this with liver disease
What drugs should you watch out with when it comes to LA
main ones:
- tricyclics
- beta blockers
- non-potassium sparing diuretics
What is the risk of giving LA to someone on tricyclics
risk of hypertension because of adrenaline
How much LA should you give to someone on tricyclics
- 2 cartridges of 1:80000
What is the risk of giving LA to those taking beta blockers
- beta blockers block adrenergic receptors
- adrenaline will compete for these receptors, reducing effectiveness
Restrict quantity of LA
What is the risk of giving someone who is on non-potassium sparing diuretics LA
- low potassium may be enhanced by adrenaline’s potassium lowering action
What is an example of a non-potassium sparing diuretic
furosemide
Who should you avoid octypressin/felypressin in
pregnant people
can induce labour
How much LA should you give those with cardiovascular issues
no more than 3 2.2ml cartridges
How do you calculate LA dose
X% = X mass / volume
Calculate the dose for 3% prilocaine
3g/100ml
= 30mg / 1ml
you have given a 2.2ml cartridge so its 2.2 x 30
What is the maximum dose of lignocaine
4.4mg/kg
How long will lidocaine last for if given as infiltration
an hour
How long will lignocaine last if given as a block
90 minutes
How long will soft tissue anaesthesia last (articaine, lignocaine, prilocaine)
180-300 minutes