Propofol-remifentanil anesthesia for tumor surgery with cortical and subcortical mapping : a retrospective study on 37 patients

Background: the anesthetic approach during functional brain mapping for tumor surgery should allow language and motor testing while providing adequate analgesia and sedation. Objectives: to describe drug dosing, level of hypnosis and anesthetic complications in patients undergoing tumor resection with functional brain mapping. Methods: total intravenous anesthesia was performed with remifentanil/propofol infusion. Ojemann cortical stimulator, electrocorticography (EcoG), EEG and EMG monitoring were used. Patients were divided into two groups: group 1 (G1) was awaken and laryngeal mask airway removed to allow language testing during cortical and subcortical stimulation; group 2 (G2) (motor testing only) was anesthetized but not paralyzed and ventilation was supported via naso-tracheal intubation throughout the procedure. BIS index monitoring was used to control hypnotic levels. Results: we retrospectively studied 37 patients admitted between July 2005 and June 2006 for tumor resection. The procedure lasted 369±61 min in G1 (n = 25, Male 15, age 40, 53-22 yrs) and 346±65 min in G2 (n = 12, Male 5, age 51, 76-23 yrs). During cortical and subcortical stimulation, G1 patients were fully awake, remifentanil was infused at 0.042±0.022 microg/kg/min, median BIS index was 85 (range 98-75), systolic arterial pressure (SAP) was 142±15 mmHg. Hypertensive crises occurred in 3 patients but rapidly resolved after β-blockers administration. Cortical and subcortical brain mapping was possible in G2 with the infusion of remifentanil at 0.074±0.023 microg/kg/min and propofol at 4.6±2.6 mg/kg/h, while median BIS index was 48 (range 20-65) and SAP was 121±19 mmHg (p < 0.05 vs G1). Acceptable correspondence was found between EcoG, EEG and BIS monitoring. Seizures occurred in both groups (G1: 8/25, G2: 7/12) but mainly resolved within 1 minute after cold saline irrigation; only 4 patients required drug administration during brain mapping. Conclusions: remifentanil/propofol infusion grants adequate sedation, analgesia and haemodynamic control while allowing functional testing during cortical and subcortical stimulation. Copyright