Dose requirement of local anaesthetic to produce grand mal seizure during stellate ganglion block.

Two case reports illustrate that low doses of local anaesthetics such as bupivacaine 2.5 mg and a mixture of bupivacaine 1.25 mg and lidocaine 5 mg can induce grand mal seizures if injected into the vertebral artery during stellate ganglion block. The effect of the dose of local anaesthetic agent and technique of administration into the stellate ganglion region discussed as is the relationship between vertebral artery blood flow and cerebral intravascular local anaesthetic concentration required to produce seizure activity. Suggestions are made concerning possible modification of the technique of anterior approach to the stellate ganglion, including test dose size, to reduce the incidence of inadvertent injection into the vertebral artery and subsequent central nervous system toxicity.