Local Anaesthetic Flashcards

1
Q

How do we prepare the syringe for LA administration

A
  1. Check the expiry date and batch number
  2. Clear rubber bung goes on (the flared part goes on first)
  3. Put the cartridge into the needle (gold bit goes in first)
  4. Bring the anchor all the way up and attach it to the syringe, looking for a single click
  5. Pull back the casing for a single click
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2
Q

What length is a yellow needle

A

35mm

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3
Q

What length is a blue needle

A

25mm

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4
Q

How do you administer an IDB

A
  • 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
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5
Q

What are the two types of LA

A

amide

ester

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6
Q

What are the 3 types of amide LA that are used through out the dental school

A

lidocaine

prilocaine

articaine

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7
Q

What is the concentration of lidocaine in the cartridge

A

2.2ml lidocaine 2% + adrenaline 1:80000

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8
Q

What is the concentration of prilocaine in the cartridge

A

3% with or without felypressin

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9
Q

What is the concentration of articaine in the cartridge

A
  • articaine 4% with adrenaline
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10
Q

Where is lidocaine metabolised

A

liver

by enzymes

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11
Q

Where is prilocaine metabolised

A

liver + kidney

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12
Q

Where is articaine metabolised

A

serum

by plasma cholinesterases

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13
Q

Where are plasma cholinesterases produced

A

liver

note this with liver disease

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14
Q

What drugs should you watch out with when it comes to LA

A

main ones:

  • tricyclics
  • beta blockers
  • non-potassium sparing diuretics
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15
Q

What is the risk of giving LA to someone on tricyclics

A

risk of hypertension because of adrenaline

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16
Q

How much LA should you give to someone on tricyclics

A
  • 2 cartridges of 1:80000
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17
Q

What is the risk of giving LA to those taking beta blockers

A
  • beta blockers block adrenergic receptors
  • adrenaline will compete for these receptors, reducing effectiveness

Restrict quantity of LA

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18
Q

What is the risk of giving someone who is on non-potassium sparing diuretics LA

A
  • low potassium may be enhanced by adrenaline’s potassium lowering action
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19
Q

What is an example of a non-potassium sparing diuretic

A

furosemide

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20
Q

Who should you avoid octypressin/felypressin in

A

pregnant people

can induce labour

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21
Q

How much LA should you give those with cardiovascular issues

A

no more than 3 2.2ml cartridges

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22
Q

How do you calculate LA dose

A

X% = X mass / volume

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23
Q

Calculate the dose for 3% prilocaine

A

3g/100ml

= 30mg / 1ml

you have given a 2.2ml cartridge so its 2.2 x 30

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24
Q

What is the maximum dose of lignocaine

A

4.4mg/kg

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25
Q

How long will lidocaine last for if given as infiltration

A

an hour

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26
Q

How long will lignocaine last if given as a block

A

90 minutes

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27
Q

How long will soft tissue anaesthesia last (articaine, lignocaine, prilocaine)

A

180-300 minutes

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28
Q

What is the maximum dose of articaine

A

7mg/kg

29
Q

What is the duration of anaesthesia for articaine given by infiltration

A

120 minutes

30
Q

What is the maximum dose of prilocaine

A

6mg/kg

31
Q

How long will a prilocaine infiltration last

A

30-45 minutes

32
Q

How long will a prilocaine block last

A

60 minutes

33
Q

What is the maximum dose for mepivacaine

A

3mg/kg

34
Q

How long does a mepivacaine infiltration last for

A

20 minutes

35
Q

How long does a mepivcaine block last for

A

40 minutes

36
Q

What are the different nerve fibres

A

A alpha, A beta, A gamma, A delta
C

37
Q

What fibres are responsible for pain

A

A delta

C

38
Q

What fibres is responsible for mechanoreceptors e.g feelings of pressure

A

A beta

A delta

C

39
Q

What fibre is responsible for dull pain

A

C

40
Q

What fibre is responsible for sharp pain

A

A delta

41
Q

What is the order that LA blocks these fibres

A

A delta fibres first, then C fibres, the Abeta fibres, then Aalpha fibres

42
Q

How does LA work

A

by stopping nerve conduction by blocking the voltage gated sodium channels.

The LA binds to the sodium channels preventing sodium influx, preventing potential generation and propagation and thus the nerve will not respond to stimuli.

43
Q

You think you might have injured yourself with the LA syringe after administering it, what should you do

A

STOP what you are doing

take off your gloves

get clinician

investigate injury site

if no injury, make sure to get new sharp before commencing again

44
Q

You think you may have injured yourself with a used sharp, you take off your gloves and you can confirm an injury. What is the protocol

A

bleed it

wash it

cover it

report it

45
Q

What is meant by ‘bleed it’ after a sharps injury

A
  • squeeze it to encourage bleeding
46
Q

What is meant by ‘wash it’ after a sharps injury

A
  • wash with liquid soap under running water
47
Q

What does sharps AWARE stand for

A
  • Apply pressure and allow to bleed
  • Wash
  • Asess - what type of injury? With what type of material? How deep is the cut?
  • Risk - blood source risk?
  • Establish contact - report
48
Q

What nerve provide the maxillary molar pulps

A
  • posterior superior alveolar nerve
49
Q

What nerve provides the maxillary premolar pulps

A
  • middle superior alveolar nerve
50
Q

What nerve supplies the maxillary anterior teeth pulp

A
  • anterior superior alveolar nerve
51
Q

What nerve supplies the maxillary buccal gingivae

A

same as what provides the corresponding tooth’s pulp

52
Q

What provides the palatal gingivae of the maxillary anteriors

A

nasopalatine

53
Q

What nerve supplies the palatal posterior maxillary gingivae

A

greater palatine

54
Q

What will a buccal infiltration in the maxilla anaesthetise

A

one of the superior alveolar nerves and that will numb up the tooth + its buccal gingivae

55
Q

What will a palatal infiltration anaesthetise

A

you will be numbing either the nasopalatine or the greater palatine

56
Q

What are the blocks you can do in the maxilla

A

nasopalatine block, greater palatine block, posterior superior nerve block, middle superior nerve block, anterior superior nerve block

57
Q

What nerve supplies the posterior mandibular teeth pulp

A
  • inferior alveolar nerve
58
Q

What nerve supplies the mandibular anterior teeth’s pulp

A
  • incisive nerve (branch of IAN)
59
Q

What nerve supplies the lingual gingivae

A

lingual nerve

60
Q

What nerve supplies the buccal gingivae of mandibular posterior teeth

A

buccal

61
Q

What nerve supplies the buccal gingiva of the premolars forward in the mandible

A

mental nerve

62
Q

What will an IDB anaesthetise

A

IAN + lingual nerve.

63
Q

What will a buccal infiltration in the mandible anaesthetise

A

A buccal infiltration, if done, would catch IAN or its incisive branch depending on the tooth as well as the buccal/mental nerve

64
Q

What will a lingual infiltration anaesthetise

A

lingual nerve

65
Q

What will a mental block anaesthetise

A

soft tissue anaesthesia (chin and lip)

may also catch the terminal nerve fibres of the IAN going to the premolars

66
Q

Describe how to do a mental block

A
  • Looking to inject between apices of the lower premolars
  • Massage LA
  • Anaesthetising mental nerve
  • May also catch nerve for the premolars (different nerve though)
67
Q

What is the procedure for a buccal infiltration

A
  • Stretch cheek
  • Puncture mucosa with correct bevel of needle
  • Advance needle over the apex of the tooth
  • If contact bone withdraw slightly
  • Aspirate
  • Anaesthesia should take around 2 minutes
68
Q

How do you confirm anaesthesia

A
  • Ask patient how it feels
  • Numb?
  • Tingly?
  • For IDB - how does tongue and lip feel?
  • Ability to sense pressure remains
  • If carrying out extraction/surgical, test mucosa with probe
69
Q

Difference between block vs infiltration

A
  • infiltration = anaesthetic deposited around terminal branches of the nerve
  • block = anaesthetic deposited beside nerve trunk