Flashcards in Local Anaesthesia in Children Deck (31)
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1
Two types of LA
• Amides - majority
• Esters
• Amides less allergenic
• Lidocaine is most common
2
Mechanism of function
• Chemical roadblock between source of pain and brain
• Electrical signals in form of action potentials
• Local anaesthetic blocks the sodium channels
• Vasoconstrictor slows removal of anaesthetic from vicinity of nerve - prolonged action
3
Contraindications?
Lidocaine
Adrenaline
Prilocaine
• Lidocaine
- hypersensitivity
- acute porphyria
- heart block
• Adrenaline
- cardiac arrhythmia
- hyperthyroidism
• Prilocaine
- known allergy
4
Other contraindications
• Bleeding disorders
- block is more likely to cause a bleed - haematoma
• Infection at injection site
- consider block instead - may neutralise infection
5
Topical anaesthetic
• Xylonor gel (5% lidocaine)
• Benzocaine gel (20%)
• EMLA cream
- mixture of LA - lignocaine and prilocaine
- usually skin, pre-iv access
6
LA solutions
• 2% (20mg/ml) lidocaine with 1:80,000 adrenaline
- gold standard
- pulpal anaesthesia 45 mins
- soft tissue anaesthesia 2-3 hours
• 3% (30mg/ml) prilocaine/Citanest with felypressin
- similar spectrum of activity
- also found in 4% (40mg/ml) solution
7
Articaine
• 4% articaine with 1:100,000 or 1:200,000 adrenaline
- aka septanest
- metabolised quicker
- good for mandibular infiltration
not for <4s
- used for paed buccal infiltration
• Contraindicated in patiens with know hypersensitivity to amide LA or hypersensitivity to sodium metabisulfite
• Intravascular injection is strictly contra-indicated and associated with convulsions
• Anti-convulsant meds can be used
8
Maximum doses
Lidocaine
Prilocaine
Articaine
Bupivicaine
4.4mg/kg
6.0mg/kg
7.0mg/kg
2.0mg/kg
9
Method for quick calculation of weight
1 cartridge/10kg of body weight on average
body weight (kg) = (age +4) x 2
e.g. 3 year old
(3 + 4) x 2 =14kg
1 year old = 10kg
5 year old = 20 kg etc.
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e.g Maximum dose for 3 year old
14kg
Max dose of lidocaine: 4.4mg/kg
Max dose for 3 year old = 4.4x14 = 62mg
2% lidocaine = 2 parts per 100 = 20 parts
per 1000 = 20mg/ml
1 cartridge = 2.2ml = 44mg
62mg/44mg = 1.4 cartridges
11
Equipment
• Adv safety plus vs traditional syringes
• Sterile single use, aspirating syringe system prevent needle stick injuries
• No recapping necessary
• Bevel indicator in orientating the bevel to the bone
• Transparent barrel to allow visualisation of aspiration
12
Needle selection
Infiltration
Block
Intraligamental
• 30 gauge - 2cm
• 27 gauge - 3mm and aspiration
• 30 gauge 1cm around gingival cuff
13
Behaviour management
• Verbal and non-verbal communication
• TLC
• Tell-show-do
• Positive renforcement
• Control
• Distraction
• Relaxation
14
Anatomical considerations
ID blocks in children
ID foramen is more posterior and inferior
Parallel to occlusal plane
Apply from contralateral side across D
Halfway between coronoid notch and pterygomandibular raphe
15
LA delivery
• Apply topical for sufficient length of time (1 min)
• Pull mucosa taut
• Establish rest for barrel
• Rotate needle round long access for easier penetration
• Inject very slowly
16
Infiltration
• Pulpal analgesia
• Topical
• Retract mucosa so it's taught
• Advance needle and perforate mucosa
• Slow injection - 1ml/15-20 secs (ant. region)
• Routine aspiration
• Smooth withdrawal and protective sheath replaced
17
Maxillary molars
• Thick malar buttress
• Molar roots on buccal aspect
• Infiltration injections
• Mesial and distal to roots - more permeable
• Block if infiltration not possible or failed
18
Maxillary molar block
• If infiltration not poss or failed
• Primary and permanent molars
• Post +/- middle superior dental nerves
• Palpate max-zygomatic buttress
• Deposit anaesthetic distal to buttress
• Massage distal aspect of maxilla
• Ask pt to occlude (coronoid process)
19
Palatal anaesthesia - initial
• Extraction/rubber dam
• Intrapapillary injections to limit pain
1. Buccal infiltration
2. Test papillae with probe
3. Penetrate to depth of 1-2mm e.g mesial and distal to UR4
4. Syringe barrel is parallel to occlusal plane and perpendicular to line of arch
5. Inject slowly and advance
20
Palatal anaesthesia - post buccal
• Continue until observe blanching of palate
• Usually takes 20-30 secs
• Repeat with the other papilla until blanching joins
• Anaesthesia of complete gingival cuff achieved
• Can progress to palatal infiltration
• Also useful in mandible (<5years old)
21
ID blocks
• Inferior dental canal foramen
• More posterior and inferior
• At level of occlusal plane in 6-9 year olds
22
ID block technique
• TOPICAL
• Open as wide as possible
• Thumb palpates external oblique ridge
• Tauten mucosa between pterygomandibular raphe and the external oblique ridge
• Insert needle from opposite side of mouth
• Barrel over 1st primary molar of other side
23
ID Block Needle Entry
• Needle enters midpoint between the external oblique ridge and pterygomandibular raphe at level of occlusal plane
• Immediately deposit a small amount of anaesthetic solution
• Gently advance with slow injection and aspiration
• Bony resistance of internal surface of ramus
• Withdraw 1mm and deposit the rest of the solution
24
ID Block rules - bone is denser with age and infiltration may not be effective
• Count number of tooth from the midline and add tooth number
• Answer is the maximum age at which infiltration alone is likely to give pulpal anaesthesia
if (age of pt) + (tooth #) < 10 = infiltration
(e.g. [4 yrs] + [LLD=4] = 8)
With articane rule of TWELVE
25
Intraligamental
• If routine infiltration or block techniques fail
• Solution introduced via periodontium
• Majority escapes through lamina dura into cancellous bone
• Potential damage to developing permanent teeth
• Contraindicated in patients at risk from bacteremia
• Caution in acute periodontal inflammation/perio disease
26
IL Injections
• 'Peripress' system - high pressure/shielded barrels/protection
• Intro needle into the inter proximal perio sulcus at 50-60º angle to occlusal plane
• Gently advance until bony resistance felt
• Firm steady pressure to inject
• 'Back pressure'
• 0.4-0.6ml mesial and distal
• Immediate analgesia
• Lips/tongue not anaesthetised
27
Alternative delivery systems
• Computer- controlled delivery
- e.g. The Wand
- controls rate of admin
- slow delivery via a line and needle
- especially useful for direct palatal analgesia
• Jet injection
- e.g Index
- 'needleless'
- jet syringe injects LA solution under pressure through mucosa and bone
- useful for soft tissue analgesia prior to traditional LA methods
28
Operator safety
• Directive 2010/32/EU - prevention from sharp injuries in the hospital and healthcare sector
• Disposable
• No recapping required
• InSafe safety syringe
• Good positioning
• Calm approach
• Hand rest
29
Reasons for failure of LA
• Acute infection
• Incorrect site
- intramuscular
- intravascular
- dense buccal bone
• Insufficient amount
• Abnormal nerve supply
• Patient immaturity - psychogenic pain
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