[Risks associated with the use of local anesthetics]

Despite widespread use, accidents following the injection of a local anaesthetic are exceptional. Some peripheral nerve lesions have been described, in keeping with mechanical distension because of accidental intravenous injection, rather than because of the anaesthetizing product itself. Generally speaking, two aetiologies are to be underlined: allergy and toxicity. Allergy is exceptional with anaesthetics of the amine type, the only commercialized kind in this country. Some cases of cutaneous allergy and bronchospasm have been reported. The accident more to be feared is toxicity, which emerges in neurological symptoms (convulsions) then cardiac symptoms (rhythm disturbance, even cardiac arrest). These accidents are associated with the sudden presence of a high concentration of local anaesthetic in the blood, resulting from accidental intravenous injection, or, more rarely, excessive resorption of a strong dosage injected into a highly vascularized area. The stronger the anaesthetic, the more this type of accident is to be feared. These accidents can be avoided by means of the observation of a rigorous technique, careful checking of the patient after the injection, and readiness to start immediate and effective reanimation at the very onset of toxication symptoms.