Plasma levobupivacaine concentrations following scalp block in patients undergoing awake craniotomy

Background. Levobupivacaine is an effective local anaesthetic agent for nerve blockade with less systemic toxicity than racemic bupivacaine. The safety and efficacy of levobupivacaine for scalp blockade during awake craniotomy have not been addressed previously. Methods. Serial arterial plasma levobupivacaine concentrations following scalp blockade were measured to 2 h in 10 patients booked for awake craniotomy for epilepsy or tumour surgery. Bilateral scalp blockade providing surgical anaesthesia was achieved with a mean dose of 177 mg (2.5 mg kg(-1), range 1.6-3.2 mg kg(-1)) of levobupivacaine (0.5%, 5 mg ml(-1)) with epinephrine (5 mu g ml(-1)) added immediately before the block insertion. Results. The maximum measured plasma levobupivacaine concentration was 1.58 (0.44) mu g ml(-1) [mean (sd)] with a mean time to peak plasma concentration of 12 (4) min. There were no episodes in any of the 10 patients of symptoms or signs suggestive of either CNS or CVS toxicity. Conclusions. This study demonstrated a relatively rapid rise of plasma levobupivacaine concentration without evidence of cardiovascular or central nervous system sequelae in a sample population of patients who may be particularly prone to perioperative seizures.