[Etomidate perfusion in neurosurgery]

In this prospective study, 20 patients undergoing mean duration (2-3 h) neurosurgical operations on fossa cranii posterior, and cervical and dorsolumbar rachis, were induced with 0.3 mg/kg etomidate bolus dose. To maintain anesthesia, etomidate perfusions at 10 micrograms/kg/min (group I) and 20 microg/kg/min (group II) were administered. Fentanyl at fractionated doses was used as analgesic without association to nitrous oxide and relaxation was achieved with pancuronium bromide. Quality of hypnosis, changes in serum concentration of cortisol as well as hemodynamic and electrolyte changes were evaluated. Serum concentrations of cortisol, glucose, sodium and potassium were measured in basal state, and during perioperative and postoperative period. Hemodynamic status was monitored and side effects were recorded. Patients of group I presented signs of deficient hypnosis consisting of marked sympathetic response. When etomidate perfusion ceased, both groups presented serum concentrations of cortisol under the lower normal limit. Six hours after operation, mean serum concentration of cortisol in group 2 patients was significantly lower than in group I patients; in their samples, a dose-dependent recovery was detected. Serum glucose concentration increased during anesthesia and operation and serum electrolyte concentration remained within normal range during perioperative and postoperative periods. Our results demonstrate that a 20 micrograms/kg/min etomidate infusion is adequate to achieve neuroanesthesia when nitrous oxide administration is contraindicated.