LA in children Flashcards
History of LA
1859 - cocaine isolated by Niemann
1880 - topical opthalmic anaesthetic, Koller
1884 - regional anaesthesia in oral cavity, Halstead
1905 - procaine synthesis
1943 - lidocaine
-1950s, 1960s, 1970s ‘modern anaesthetics’
Dental LAs
Two groups: amides and esters
Most are amides
Amides less allergenic than amides
Lidocaine - gold standard
How do anaesthetics work?
Chemical roadblock between the source of the pain and the brain
Electrical signals = action potentials
Local anaesthetics block the sodium channel –> nerve signals cannot be transmitted
Vasoconstrictor –> slows the removal of the anaesthetic from the vicinity of the nerve –> prolongs anaesthetic action
To use or not to use?
Avoid GA if possible, Poswillo report, 1990
‘LA is the mainstay of pain control during dental treatment’, GDC Standards 2005
Child - age, cooperation
Procedure - 1 filling or 8 fillings
Effects of painful experience? - 1 extraction fine, 2nd one will be scared
Primary teeth are ‘insensitive’ to pain - not true!
Possible contraindications
Lidocaine - known hypersensitivity - acute porphyrias - heart block Adrenaline - cardiac arrhythmias - hyperthyroidism Prilocaine - known allergy Bleeding disorders - infiltration techniques (more likely block will cause bleed) Infection at injection site - consider block techniques
Topical anaesthetic
Xylonor gel (5% Lidocaine) Paeds clinic - now used Benzocaine gel (20%), bubble gum flavoured - used to be used EMLA Cream (Eutectic mixture of local anaesthetics – 5% mixture lignocaine + prilocaine) usually skin, pre-iv access
Local anaesthetic solutions
2%(20mg/ml) lidocaine with 1:80,000 adrenaline (2.2ml syringe)
- gold standard
- pulpal anaesthesia 45mins
- soft tissue anaesthesia 2-3hours
3%(30mg/ml) prilocaine (Citanest) with felypressin
- similar spectrum of activity
- also 4%(40mg/ml) plain solution
Articaine solution
4% articaine with 1:100,000 or 1:200,000 adrenaline Septanest Similar performance Metabolism quicker Good for mandibular infiltrations? Not to be used<4 years
Articaine contraindications
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
Maximum doses
Lidocaine: 4.4mg/kg
Prilocaine: 6.0mg/kg
Articaine: 7.0mg/kg (children 5mg/kg)
Bupivicaine (used for longer procedures, longer acting) 2.0mg/kg
How much does a child weigh?
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. BUT a lot of children are overweight! Try to weigh them
Maximum dose for 3 year old
Weight = 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
LA maximum dose
1 cartridge per 10kg of body weight
e.g. 1/10 cartridge per kg
3-year-old=14kg
14/10=1.4 cartridges
La armamentarium
SafetyPlus system
Sterile, single use, aspirating syringe system, designed to prevent needle stick injuries
No recapping necessary, conforms with guidelines
Bevel indicator to assist in orientating bevel to bone
Transparent barrel to allow visualisation of aspiration
Needle selectiong
Infiltration anaesthesia
- 30-gauge 2cm needle
Block anaesthesia - 27-gauge 3cm needle - ability to aspirate Intraligamental anaesthesia - 30 gauge 1cm needle *As length of needle increases, needle diameter decreases*
