Intravenous anesthesia with propofol in intracranial surgery]

OBJECTIVES: To analyze the repercussions of intravenous anesthesia with propofol as the single hypnotic drug on intracranial pressure (ICP) and cerebral perfusion pressure (CPP), and also to study the time until recovery from anesthesia and to tracheal extubation as well as intraoperative hemodynamic changes in patients undergoing surgery to remove a supratentorial brain tumor. PATIENTS AND METHODS: Twenty-three ASA I/II patients scheduled for exeresis of a supratentorial brain tumor were studied. A fiberoptic sensor placed in direct contact with the dura mater was used to measure ICP. Anesthetic induction was achieved with propofol (2 mg/kg). Propofol (12 and 9 mg/kg/h for 10 min and 6 mg/kg/h throughout the rest of the operation) was used for maintenance. Mean arterial pressure (MAP), heart rate (HR), ICP and CPP were recorded at baseline and 1, 2, 3 and 4 min after induction, during laryngoscopy and tracheal intubation; 1, 3, 5, 10, 15 and 20 min after tracheal intubation (L + 1, L + 3, L + 5, L + 10, L + 15, L + 20), upon placement of a craniostat; upon skin incision; upon withdrawal of propofol perfusion; and during extubation. The following variables were recorded after awakening: time until eye opening after receiving a verbal command, time until extubation and time until orientation. Analysis of variance for repeated measures (ANOVA) was performed on the results. RESULTS: MAP decreased significantly from baseline at the following times: during the post-induction period, upon placement of the craniostat, upon skin incision and when the propofol infusion was switched off. HR increased significantly during laryngoscopy and at the following moments: intubation, post intubation (L + 1, L + 3, L + 5), craniostat placement, and extubation. ICP was lower throughout the surgical period except during laryngoscopy, when this variable increased significantly. CPP decreased significantly after induction and returned to baseline after intubation. CPP was significantly higher after surgery. Recovery times after weaning from propofol infusion until eye opening in response to an order and until orientation were 13 +/- 3 and 22 +/- 4 min, respectively. The mean interval between withdrawal of propofol until extubation was 18 min. CONCLUSIONS: Intravenous anesthesia with propofol in intracranial surgery (supratentorial tumors) affords hemodynamic stability and lowers ICP except during laryngoscopy. Early recovery from anesthesia allows for neurological assessment and vigilance during the immediate postoperative period.