Local Anesthetic Systemic Toxicity

Abstract

The incidence of local anesthetic systemic toxicity varies widely from report to report, but serious cases are rare. We should recognize that patients who undergo regional anesthesia may have clinical conditions that are vulnerable to local anesthetic systemic toxicity. Reduction of the local anesthetic agent to a minimum required dose, careful monitoring, and preparation for prompt treatment are essential. Lipid resuscitation is recommended for severe local anesthetic systemic toxicity. However, its evidence has not been established yet and there is controversy regarding the dose of epinephrine.

On rare occasions, benzocaine, propitocaine, and other local anesthetics bring about methemoglobinemia that presents desaturation or cyanosis refractory to oxygen administration. Diagnosis can be confirmed by CO-oximetry, and treatment with methylene blue should be commenced when symptoms appear or methemoglobin concentration exceeds 30%.