Eutectic Mixture of Local Anesthesia (EMLA) Toxicity after Application for Laser Surgery: A Case Report

Abstract

Objective:

Eutectic mixture of local anesthesia (EMLA) is widely used and generally regarded as safe. However, the potentially devastating effects of EMLA cannot be forgotten. It is the objective of this paper to discuss the presentation and treatment of EMLA toxicity as it applies to cosmetic surgery.

Methods:

A case report.

Case Presentation:

A 29-year-old white woman sought cosmetic treatment of abdominal striae with laser at an outpatient surgical center. The patient arrived a half-hour before her appointment, complaining of parasthesias, and soon became agitated. Generalized seizure and respiratory arrest ensued. The patient was emergently intubated in the office and transferred to the hospital, where she was treated for lidocaine toxicity. Phenobarbital coma was induced. As lidocaine levels fell, the phenobarbital was stopped, and the patient was eventually extubated.

Discussion:

Lidocaine blood levels ranging from 0.5 to 5 μg/mL are considered therapeutic. At therapeutic levels, side effects may include burning, transient paleness, erythema, and edema at the site of application. At such levels, lidocaine has anticonvulsant properties. As the levels approach 5 μg/mL, however, minor central nervous system (CNS) symptoms begin to manifest. Typically, these include vertigo, drowsiness, tinnitus, dysarthria, and perioral numbness. As levels approach or exceed 7.5 μg/mL, objective CNS signs, such as tremors, confusion, and shivering, are evident. By 10 μg/mL seizures arise. Respiratory depression and, ultimately, coma will eventually result. Cardiovascular toxicity may also result, leading to bradycardia, dysrhythmias, and eventually cardiac arrest.

Conclusion:

Management for lidocaine toxicity should focus on treating the seizures and cardiovascular collapse. Initially, the treating physician must establish and maintain vital functions, and lidocaine levels should be measured every 12 hours. It is important that in all situations where EMLA is used, a physician capable of the acute management of toxicity is present. Additionally, facilities in which EMLA is used should be properly equipped with the tools necessary for managing EMLA toxicity.