Systemic Toxicity of Local Anesthetics

Abstract

 The administration of local anesthetics carries the potential hazard of producing central nervous system and cardiovascular toxicity. Severe cardiovascular toxicity can occur when bupivacaine is accidentally injected intravascularly, leading to fatal dysrhythmia and cardiac arrest. Bupivacaine-induced cardiovascular toxicity is resistant to conventional treatment, and resuscitation is difficult. Recently, lipid therapy, using an infusion of lipid emulsion, has been reported to be effective for the resuscitation of bupivacaine-induced cardiovascular toxicity. Ropivacaine and levobupivacaine were developed as new long-acting amide local anesthetics with less cardiovascular toxicity. They consist of pure levorotatory S-enantiomers. In an experimental study in rats, we found that the cumulative dose inducing cardiac arrest was greater for ropivacaine than for bupivacaine and levobupivacaine. We also found that ropivacaine-induced cardiac arrest was more responsive to treatment than that induced by bupivacaine or levobupivacaine. Although ropivacaine has a greater margin of safety between the doses required to induce seizures and cardiac arrest, several cases of ropivacaine-induced cardiac arrest have been reported. Therefore, attention should be paid to the potential hazards of ropivacaine in clinical practice.