Painful procedures, such as venipuncture, intravenous cannulation, lumbar puncture, and laceration repair, are common in pediatrics and cause distress to children and their parents. The stress response to pain is associated with metabolic and hormonal changes that are attenuated by anesthesia [1,2].
Anesthesia can be provided by injection. However, topical anesthetics can be applied painlessly without needles and reduce the need for physical and chemical restraints . They also avoid the tissue distortion that occurs with infiltrated anesthetics .
Nonpharmacologic interventions (eg, behavioral techniques, cognitive techniques) are an essential part of any attempt to attenuate pain in the conscious child and enhance the benefit of local anesthesia. (See "Procedural sedation in children outside of the operating room", section on 'Nonpharmacologic interventions'.)
The use of topical anesthetics is reviewed here. A general approach to the management of pain and sedation in children, and prevention and treatment of neonatal pain are discussed elsewhere. (See "Procedural sedation in children outside of the operating room" and "Prevention and treatment of neonatal pain".)
LET is a combination of lidocaine (4 percent), epinephrine (0.1 percent), and tetracaine (0.5 percent) available as an aqueous solution or methylcellulose based gel. The local anesthetics cause sensory and motor blockade primarily by reversible inhibition of axonal sodium channels, blocking conduction of action potentials . This results in numbness and weakness. Epinephrine causes local vasoconstriction that slows systemic absorption and metabolism of the anesthetics . Lidocaine, in the amide class of anesthetics, is metabolized by the liver; tetracaine, in the ester class, is metabolized in plasma by pseudocholinesterase .