Resident: J. Hencler
Date: 03/16/2011
Author: AAPD
Journal: AAPD Reference Manual V32/NO4 10/11
Major topic: LA
Type of Article: Reference/Review
Main Purpose:
To provide a set of accepted guidelines that will help practitioners make informed decisions when using LA to control pain in infants, children, adolescents, and individuals with special needs during the delivery of oral health care.
Background/Contraindications:
Two types: esters and amides. LAs are vasodilators. Vasoconstrictors added to constrict blood vessels, slow the rate of absorption which lowers risk of toxicity, and prolong the mechanism of action. Epi is contraindicated in patients w/ hyperthyroidism. Its dose should be kept minimal in patients taking tricyclic antidepressants since dysrhythmias may occur. Vasoconstrictors levonordefrin and norepi are absolutely contraindicated in these patients. Patients w/ significant CV disease, thyroid dysfunction, diabetes, or sulfate sensivity and those taking MAO inhibitors, tricyclic antidepressants, or phenothiazines may require med consult to determine need for LA w/out vasoconstrictor. When halogenated gases such as halothane are used for GA, the myocardium is sensitized to epi so use caution w/ use of LA w/ epi. Amide LAs are no longer contraindicated in patients w/ family hx of malignant hypothermia. The inflammatory process of infection inhibits LA mechanism of action due to lowering of pH. Also, inserting needle into active site of infection may lead to spread of infection. Reports of paresthesia are more common w/ articaine and prilocaine. The risk of permanent paresthesia is 1:1,200,000 for 0.5%, 2%, and 3% LAs and 1:500,000 for 4% LAs. Long acting LAs such as bupivicaine are not recommended for children and special needs patients.
Guidelines/Recommendations:
Topical anesthetic may be used to reduce discomfort associated w/ needle penetration. Understand properties of topical anesthetic. A metered spray is suggested is an aerosol preparation is used. Systemic absorption of the drugs in topical anesthetics must be considered when calculation the total amount of anesthetic administered.
Always use aspirating syringes. 23- through 30-gauge needles may be used for intraoral injections, since blood can be aspirated through all of them. Aspiration can be more difficult w/ smaller gauge needles. Needles should not be bent.
Documentation must include type and dosage of LA and vasoconstrictor and may include type of injection, needle selection, and patient response. When LA is administered in conjunction w/ sedative drugs, the doses of all agents must be noted on a time-based record. In patients for whom the max dose of LA may be a concern, the weight should be documented pre-operatively. Document should include post-injection instructions were reviewed with child and parent.
After injection, someone should remain w/ patient while LA takes effect. Most adverse drug reactions develop either during the injection or w/in 5-10 minutes. Overdose of LA can result from accidental intravascular injection (always aspirate) or repeated injections. LA causes a bi-phasic reaction (excitation followed by depression) in the CNS. The CV system response to LA toxicity is also bi-phasic. Allergy to LA is not dose dependent but is due to patient’s capacity to react to even a small dose. True allergy to an amide is very rare. For patients w/ an allergy to bisulfates, use a LA w/out a vasoconstrictor.
Residual soft tissue anesthesia should be minimized in pediatric and special needs patients to decrease risk of self-inflicted post-op injuries. Practitioners should review with parents/caregivers regarding behavioral precautions to reduce self inflicted soft-tissue trauma.
Alternative techniques of LA delivery such as PDL, intraligamentary, peridental, intraseptal, and intrapulpal injections may be considered to minimize dose of LA, improve patient comfort, and improve anesthesia effect.
To avoid excess doses for the sedated patient, calculate a max dose. The dosage of LA should NOT be altered if N2O/O2 is used. When GA is employed, LA may be used to reduce the maintainence dose of anesthetic drugs.
Assessment of article: Great review of guidelines.
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