[Grand mal convulsion after an interscalene block with ropivacaine]

We report a case of grand mal convulsion due to inadvertent intravascular injection of ropivacaine. An 83-year-old woman was scheduled for upper limb surgery. The interscalene block was performed with neurostimulator and 0.5% ropivacaine 30 ml was injected after careful negative aspiration. Approximately 3 min after the injection, the patient lost consciousness and developed generalized convulsion, which was repeated 7 times. The seizures stopped after administration of diazepam 10 mg and thiamylal 250 mg i.v. Trachea was intubated and lungs were mechanically ventilated. During the seizure, arterial blood pressure increased from 180/110 mmHg to 190/120 mmHg and heart rate changed from 90 beats x min(-1) to 88 beats x min(-1). Ventricular premature beats were observed sporadically but stopped spontaneously. After the episode, the operation was performed under general anesthesia (nitrous oxide 50% and sevoflurane 1.5-2% in oxygen 50%). The patient recovered uneventfully after the operation. Although careful aspiration was done before the injection of ropivacaine, inadvertent intravenous injection could have occurred during the administration. Intermittent aspiration should be indispensable during the administration, because a large dose of local anesthetic is necessary for interscalene block. In this case, the only cardiovascular manifestation was ventricular premature beats indicating that ropivacaine has less cardiotoxicity.