EFFECTS OF A SINGLE PREOPERATIVE DEXMEDETOMIDINE DOSE ON ISOFLURANE REQUIREMENTS AND PERIOPERATIVE HEMODYNAMIC STABILITY

In a double-blind, placebo-controlled study we investigated the effect of a single pre-induction intravenous dose of dexmedetomidine 2 mu g. kg(-1) on anaesthetic requirements and peri-operative haemodynamic sta bility in 50 patients undergoing minor orthopaedic and general surgery . Patients were anaesthetised with nitrous oxide/oxygen/fentanyl, supp lemented if necessary with isoflurane. The mean (SD) intra-operative i soflurane concentration was lower in the dexmedetomidine-treated patie nts than controls (0.01 (0.03)% compared to 0.1 (0.1)%; p = 0.001) alt hough six of the 25 treated patients required isoflurane at some stage . The haemodynamic response to tracheal intubation and extubation was reduced in the dexmedetomidine group as uas intra-operative heart rate variability; postoperative analgesic and anti-emetic requirements and peri-operative serum catecholamine concentrations were lower in the d exmedetomidine group. Hypotension and bradycardia occurred more freque ntly after dexmedetomidine.