Very young children are not suited to treatment under local anaesthesia as they will
not provide the degree of cooperation required for completion of treatment. A child
who cannot differentiate between painful and non-painful stimuli (such as pressure) is
unsuitable for treatment under local anaesthesia.
Mental or physical handicap
Local anaesthesia is contraindicated where the degree of handicap prevents
cooperation.
Treatment factors
Certain factors related to the proposed treatment may contraindicate the use of local
anaesthesia. These factors include duration and access. Prolonged treatment sessions,
especially if some discomfort may be produced such as during surgical procedures,
cannot satisfactorily be completed under local anaesthesia. It is unreasonable to
expect a child to cooperate for more than 30-40 min under such circumstances even
when sedated. Similarly, where access proves difficult or uncomfortable, for example,
during biopsies of the posterior part of the tongue or soft palate, satisfactory
cooperation may be impossible under local anaesthesia.
Acute infection
As mentioned above, acute infection reduces the efficacy of local anaesthetic
solutions.
5.8.2 Specific agents
Allergy
Allergy to a specific agent or group of agents is an absolute contraindication to the
use of that local anaesthetic. Cartridges containing latex in their bung must be avoided
in those allergic to this material.
Medical conditions
Some medical conditions present relative contraindications to the use of some agents.
For example, in liver disease the dose of amide local anaesthetics should be reduced.
Ester local anaesthetics should be avoided in children who have a deficiency of the
enzyme pseudocholinesterase.
Poor blood supply
The use of vasoconstrictor-containing local anaesthetic solutions should be avoided in
areas where the blood supply has been compromised, for example after therapeutic
irradiation.
5.8.3 Specific techniques