Plasma levobupivacaine concentrations following scalp block in patients undergoing awake craniotomy

Background. Levobupivacaine is an effective local anaestheticagent for nerve blockade with less systemic toxicity than racemicbupivacaine. The safety and efficacy of levobupivacaine forscalp blockade during awake craniotomy have not been addressedpreviously. Methods. Serial arterial plasma levobupivacaine concentrationsfollowing scalp blockade were measured to 2 h in 10 patientsbooked for awake craniotomy for epilepsy or tumour surgery.Bilateral scalp blockade providing surgical anaesthesia wasachieved with a mean dose of 177 mg (2.5 mg kg^–1, range1.6–3.2 mg kg^–1) of levobupivacaine (0.5%, 5 mgml^–1) with epinephrine (5 µg ml^–1) added immediatelybefore the block insertion. Results. The maximum measured plasma levobupivacaine concentrationwas 1.58 (0.44) µg ml^–1 [mean (SD)] with a meantime to peak plasma concentration of 12 (4) min. There wereno episodes in any of the 10 patients of symptoms or signs suggestiveof either CNS or CVS toxicity. Conclusions. This study demonstrated a relatively rapid riseof plasma levobupivacaine concentration without evidence ofcardiovascular or central nervous system sequelae in a samplepopulation of patients who may be particularly prone to perioperativeseizures.