Practical Local Anaesthesia for Special Needs Patients

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Practical Local Anaesthesia for Special Needs
Patients

• John Meechan

London 5th December, 2003
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Problems

• before the injection
• giving the injection
• early post-injection period
• late post-injection period

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Problems

• before the injection
• giving the injection
• early post-injection period
• late post-injection period

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Problems giving the injection

• lack of access for IANB
• lack of access for palatal injections

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Overcoming limited access

• closed mouth block
• palate via buccal papillae
• intraligamentary/intra-osseous techniques

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The Akinosi technique
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The Akinosi technique
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Palatal access
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Problems in the early post-injection period

• due to local anaesthetic
• due to vasoconstrictor

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Unwanted effects of the local anaesthetic

• failure
• allergy
• systemic effects
• toxicity
• drug interactions

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Unwanted effects of the local anaesthetic

• failure
• allergy
• systemic effects
• toxicity
• drug interactions

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Toxicity

• intravascular injection
• too large a dose
• inability to metabolise

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self-aspirating
non-aspirating/ self-aspirating
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initial aspiration force
subsequent force
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Why 2.2mL?
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Why 2.2mL?
44mg lidocaine
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Whats so special about 44?
International dialling code for the U.K
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2
2.2 ml
1.5 litres plasma
44mg lidocaine
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2
29mg/L
2.2 ml
1.5 litres plasma
44mg lidocaine
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2
29mg/L
2.2 ml
1.5 litres plasma
44mg lidocaine
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10mg/L
2
29mg/L
2.2 ml
1.5 litres plasma
44mg lidocaine
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CNS toxicity
5mg/L
10mg/L
2
29mg/L
2.2 ml
1.5 litres plasma
44mg lidocaine
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CNS toxicity
5mg/L
4.5mg/L
2
12.6mg/L
2.2 ml
44mg lidocaine
3.5 litres plasma
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44
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Maximum dose of lidocaine and mepivacaine

• 4.4mg/kg
• ceiling 300mg

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The one tenth of a cartridge per kilogram rule
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Maximum doses
Drug Max dose 1/10th cartridge
2 lidocaine 4.4mg/kg 3.6 - 4.4mg
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Maximum doses
Drug Max dose 1/10th cartridge
2 lidocaine 4.4mg/kg 3.6 - 4.4mg
2 mepivacaine 4.4mg/kg 4.0mg
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Maximum doses
Drug Max dose 1/10th cartridge
2 lidocaine 4.4mg/kg 3.6 - 4.4mg
2 mepivacaine 4.4mg/kg 4.0mg
3 mepivacaine 4.4mg/kg 6.0 mg
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Maximum doses
Drug Max dose 1/10th cartridge
2 lidocaine 4.4mg/kg 3.6 - 4.4mg
2 mepivacaine 4.4mg/kg 4.0mg
3 mepivacaine 4.4mg/kg 6.0 mg
3 prilocaine 6.0mg/kg 6.6mg
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Maximum doses
Drug Max dose 1/10th cartridge
2 lidocaine 4.4mg/kg 3.6 - 4.4mg
2 mepivacaine 4.4mg/kg 4.0mg
3 mepivacaine 4.4mg/kg 6.0 mg
3 prilocaine 6.0mg/kg 6.6mg
4 prilocaine 6.0mg/kg 8.0mg
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Maximum doses
Drug Max dose 1/10th cartridge
2 lidocaine 4.4mg/kg 3.6 - 4.4mg
2 mepivacaine 4.4mg/kg 4.0mg
3 mepivacaine 4.4mg/kg 6.0 mg
3 prilocaine 6.0mg/kg 6.6mg
4 prilocaine 6.0mg/kg 8.0mg
4 articaine 7.0mg/kg 6.8 - 8.0mg
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Child of 5 years

• weighs 18 - 20kg
• maximum dose 88mg (2 x 2.2ml cartridges)

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Unwanted effects of the vasoconstrictor

• toxicity
• systemic effects (especially in medically
  compromised)
• drug interactions

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Unwanted effects of the vasoconstrictor

• toxicity
• systemic effects (especially in medically
  compromised)
• drug interactions

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Systemic effects of epinephrine

• do they occur at normal doses?

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0.6
volunteers
Blood glucose mmol/L
0
- 0.6
0
20
30
10
Time (mins)
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0.6
volunteers
third molar pts
Blood glucose mmol/L
0
- 0.6
0
20
30
10
Time (mins)
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0.6
volunteers
third molar pts
sedated third molar pts
Blood glucose mmol/L
0
- 0.6
0
20
30
10
Time (mins)
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0.6
volunteers
third molar pts
sedated third molar pts
Blood glucose mmol/L
third molar pts (no epinephrine)
0
P lt 0.05
- 0.6
0
20
30
10
Time (mins)
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Total epinephrine (ug)
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Conclusion

• Epinephrine produces systemic effects at
  dental doses.

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ASA VI
ASA III-IV
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• supersensitive
• no vagus

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Heart rate vs Time

Change from base- line heart rate (bpm)
20
10
0
-5
0
10
b-l
Time (min)
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Conclusion

• The effects of epinephrine are exaggerated in
  some medically compromised patients.

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K
K
K
K
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Effect of lidocaine with epinephrine on plasma
potassium concentration
0
volunteers
patients

Plasma K mmol/L
-0.3
0
10
Time (mins)
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Effect of lidocaine with epinephrine on plasma
potassium concentration
0
volunteers
patients

Plasma K mmol/L
diuretic pts
-0.3
0
10
Time (mins)
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Effect of lidocaine with epinephrine on plasma
potassium concentration
0
volunteers
patients

Plasma K mmol/L
diuretic pts
beta-blocker pts
-0.3
0
10
Time (mins)
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Effect of lidocaine with epinephrine on plasma
potassium concentration
0
volunteers
patients

Plasma K mmol/L
diuretic pts
beta-blocker pts
diuretics no epi
-0.3
0
10
Time (mins)
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Conclusion

• Epinephrine has drug interactions at dental
  doses.

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Problems in the late post-injection period

• self-inflicted trauma

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Avoiding self-inflicted trauma

• reduce area of soft tissue anaesthesia
• intraligamentary anaesthesia
• intra-osseous anaesthesia
• palatal approaches to pulp

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Intraligamentary anaesthesia
intraligamentary
injection
dentine
gingiva
pulp
pdl
alveolus
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Intraligamentary anaesthesia
intraligamentary
injection
dentine
gingiva
pulp
alveolus
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Intraligamentary anaesthesia
intraligamentary
injection
dentine
gingiva
pulp
alveolus
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Intraligamentary anaesthesia
intraligamentary
injection
dentine
gingiva
pulp
alveolus
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Intraligamentary and intra-osseous anaesthesia
intraligamentary
injection
dentine
gingiva
pulp
intra-osseous
injection
alveolus
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Intraligamentary and intra-osseous anaesthesia
intraligamentary
injection
dentine
gingiva
pulp
intra-osseous
injection
alveolus
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Success of intraligamentary anaesthesia depends
on

• tooth
• least successful with lower incisors
• solution
• dependent upon vasoconstrictor concentration

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Medical problems and intraligamentary anaesthesia

• haemophilia
• endocardial disease

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Palatal approaches to pulp

• ? possible due to computerised injection systems
• palatal anterior superior alveolar nerve block
• anterior middle superior alveolar nerve block

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Palatal Anterior SuperiorAlveolar Nerve Block
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Anterior Middle Superior Alveolar Nerve Block
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Conclusions

• adapting local anaesthetic technique can overcome
  difficulties in access and limit soft tissue
  anaesthesia
• local anaesthetic doses must be controlled
• vasoconstrictors produce systemic effects
• effects of vasoconstrictors are exaggerated in
  medically compromised patients
• dental epinephrine has drug interactions

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