RESUMEN
BACKGROUND: If epileptogenic foci are close to eloquent areas of the brain, awakening is needed for functional mapping during seizure surgery. In these cases adequate analgesia and sedation are needed. However sufficient dosage of intravenous anesthetics leads to many side effects. The authors used propofol and fentanyl infusion combined with scalp nerve block to reduce the severity of side effects from overdose of anesthetics. METHODS: The subjects were adult patients who would undergo awake craniotomy. After administering fentanyl 50~100 mcg intravenously, scalp nerve block was done to supraorbital, supratrochlear, auriculotemporal and lesser and greater occipital nerves of the surgical side with 0.25% bupivacaine containing 1 : 200,000 epinephrine. The anterior temporal region was infiltrated with the same local anesthetics. Oxygen was given by nasal cannula. During operation fentanyl was infused. Propofol was infused except during the awake period. Invasive arterial blood pressure, end-tidal CO2 and respiratory rate were monitored throughout the operation and arterial blood gas analysis was done intermittently. RESULTS: During total anesthesia time (410.3 39.9 min) propofol 16.2 6.3 mg/kg and fentanyl 11.9 3.7 mcg/kg were administered. The results of scalp nerve block were satisfactory. Brain swelling and transient decrease in respiratory rate were noticed in six patients and oxygen desaturation to 94% in one patient. All the patients were cooperative and the above problems were solved by reducing drug infusion rates. CONCLUSIONS: Propofol and fentanyl infusion with scalp nerve block may be an adequate method of anesthetic management for awake craniotomy.