Influence of intravenous clonidine pretreatment on anesthetic requirements during bispectral EEG-guided sevoflurane anesthesia

Study Objective: To assess the anaesthetic effects of clonidine during sevoflurane anaesthesia guided by the bispectral index (BIS), which is a processed EEG variable correlated with anaesthetic-hypnotic depth. Design: Placebo-controlled, double-blind clinical trial Settings: Elective laparoscopic surgery Patients: 60 ASA physical status I patients scheduled for laparoscopic surgery Interventions: Patients received either clonidine (3 mu g/kg, 15 min before induction) or placebo premedication for a sevoflurane-induced and sevoflurane-maintained anaesthesia. Sevoflurane was titrated against a BIS held between 40 and 50. Analgesia was provided by local infiltration with bupivacaine. Need for postoperative analgesia was recorded. Results and Conclusion: Mean sevoflurane requirements were not lower with clonidine pretreatment. There was statistically better perioperative hemodynamic stability (i.e., fewer episodes of hypertension and tachycardia) without clinical relevance. A decreased need for postoperative analgesia was observed. (C) 2000 by Elsevier Science Inc.