Importância do droperidol e do metoprolol na anestesia com profolol, alfentanil e óxido nitroso para septoplasias e turbinectomias / Importance of droperidol and metropol in anesthesia with propofol, alfentanil and nitrous oxide for septoplasties and turbinectomies

RESUMO

Background and Objectives - The objectives of this study were to observe: a) if the association of droperidol and metoprolol to a propofol-alfentanil anesthesia contributes to maintain low blood pressure and heart rate to facilitate septoplasties and turbinectomies; b) if nitrous oxide interacts with this association and c) if recovery from anesthesia is influenced by these drugs. Methods - Eighty patients classifield as ASA physical status I of both sexes were studied. Premedication consisted of midazolam 0.1 mg.Kg-1 intramusculary. Induction of anesthesia was performed with alfentanil 25 ug.Kg-1, propofol 0.8-1.5 mg.Kg-1 and vecuronium -.1 mg.Kg-1, followed by tracheal intubation and mechanical ventilation. The patients were allocated into three groups: Group A (control): anesthesia was maintained with intermittent doses of alfentanil, continuous infusion of propofol and ventilation with 100 per cent oxygen; Group B: droperidol 0.15 mg.Kg-1 and metropolol 0.1 mg.Kg-1 were added to the technique and the administration of alfentanil and propofol were adjusted to maintain hemodynamic parameters similar to those observed in Group A; Group C: received the same technique as in Group B, but ventilation was performed with a N2O/O2 mixture (66-69 per cent/34-31 per cent). Arterial blood pressure was maintained 30 per cent below the control values (minimum of 80mmHg) and heart rate at approximately 60 beats/min. Recovery from anesthesia was evaluated as time required for reflexes and consciousness to retur. Dose requirements of propofol and alfentanil were comparede in the studied groups. Results - There were significant differences between the initial and final values of blood pressure as compared to those observed during the resection of the septum and the use of the scope in turbinectomies and closure in each group. Systolic blood pressure was significantly higher in Group A as compared to the other groups. Heart rete was significantly lower in patients receiving metoprolol and droperidol. There were significant differences in alfentanil and propofolconsumption among the studied groups. Patients receiving droperidol, metoprolol and N2O recovered faster. Conclusions - The addition of droperidol and metoprolol to a propofol-alfentanil technique contributes to reduce blood pressure and heart rate to adequate levels for the performance of septoplasties and turbinectomies and to reduce total consumption of alfentanil and propofol. The association of nitrous oxide further reduces drug consumption and promotes faster recovery