A dreaded complication of local anesthetic use in regional anesthesia is systemic toxicity from unintentional intravascular local anesthetic injection. Although systemic toxic reactions are not common after peripheral nerve block, 7.5 to 20 events per 10, 000 in adults, 1 they can be life-threatening and resistant to treatment. 2–6 Recent data from an American Society of Anesthesiology Closed Claims Project demonstrate that unintentional intravenous local anesthetic injection was the second largest category of block-related regional anesthesia claims that resulted in death or brain damage. 7

The manifestations of local anesthetic toxicity range from local neurotoxic and myotoxic reactions to cardiovascular collapse and coma. Central nervous system toxicity presents as a spectrum that includes shivering, muscle twitching, tonic-clonic seizures, hypoventilation, and respiratory arrest. 8 Cardiovascular toxicity primarily manifests as arrhythmias and myocardial depression. 9–14 Local anesthetic overdose can cause a variety of arrhythmias, including atrial and ventricular conduction delays, complete heart block, asystole, ventricular ectopy, ventricular tachycardia, torsades de pointes, and ventricular