Dexmedetomidine and neurocognitive testing in awake craniotomy

Patients are selected for awake craniotomy when the planned procedure involves eloquent areas of the brain, necessitating an awake, cooperative patient capable of undergoing neurocognitive testing. Different anesthetic combinations, including neurolept, propofol with or without opioid infusions, and asleep-awake-asleep techniques, have been reported for awake craniotomy. In all these techniques, respiratory depression has been reported as a complication. In this case series dexmedetomidine, the highly selective alpha-2 adrenoreceptor agonist, was selected for its lack of respiratory depression as well as its sedative and analgesic properties. The charts of 10 consecutive patients who underwent awake craniotomy with dexmedetomidine infusion were reviewed. Five of the patients underwent "asleep-awake" technique with a laryngeal mask airway and volatile agent. Five patients received moderate to conscious sedation. All patients received a dexmedetomidine load of 0.5 to 1.0 microg/kg over 20 minutes followed by an infusion at rates of 0.01 to 1.0 microg/kg per hour. Four patients had extensive sensory and motor testing, and six underwent neurocognitive testing, including naming, reading, counting, and verbal fluency. There were no permanent neurologic deficits, except one patient who had an exacerbation of preoperative language difficulties. Dexmedetomidine appears to be a useful sedative for awake craniotomy when sophisticated neurologic testing is required.