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

Study Objective: To assess the anaesthetic effects of clonidine during sevo flurane anaesthesia guided by the bispectral index (BIS), which is a proces sed 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 surg ery Interventions: Patients received either clonidine (3 mu g/kg, 15 min before induction) or placebo premedication for a sevoflurane-induced and sevoflur ane-maintained anaesthesia. Sevoflurane was titrated against a BIS held bet ween 40 and 50. Analgesia was provided by local infiltration with bupivacai ne. Need for postoperative analgesia was recorded. Results and Conclusion: Mean sevoflurane requirements were not lower with c lonidine pretreatment. There was statistically better perioperative hemodyn amic stability (i.e., fewer episodes of hypertension and tachycardia) witho ut clinical relevance. A decreased need for postoperative analgesia was obs erved. (C) 2000 by Elsevier Science Inc.