Arterial lignocaine concentrations following cervical plexus blockade for carotid endarterectomy

Arterial lignocaine concentrations were measured in twenty-six patients who had carotid endarterectomy performed under deep and superficial cervical plexus blockade. A dose of 6 mg/kg of 1.5% lignocaine with 1:200,000 adrenaline was used, as well as additional supplementation by the surgeons when required. Concentrations obtained produced a mean peak of 5 micrograms/ml and were similar to those previously reported from multiple bilateral intercostal blockade, which is the regional technique widely considered to produce the highest systemic levels of local anaesthetic. Apart from one peak concentration of 16.9 micrograms/ml, levels were well below the convulsion threshold. We find the technique acceptable and safe for carotid surgery and lignocaine toxicity is not identified as a problem.