title: Effect of clonidine and dexmedetomidine premedication on perioperative oxygen consumption and haemodynamic state.
abstract: Premedication has been shown to affect both oxygen consumption and metabolic rate. We have compared the perioperative metabolic and haemodynamic effects of two alpha 2-agonists, clonidine and the more selective dexmedetomidine, in 30 ASA I patients undergoing plastic surgical procedures under general anaesthesia. Patients were premedicated with clonidine 4 micrograms kg-1 (n = 10), dexmedetomidine 2.5 micrograms kg-1 (n = 10) or saline (n = 10) i.m. The doses of clonidine and dexmedetomidine were intended to be equipotent. The maximum decrease in preoperative oxygen consumption was 8% and decreases in systolic and diastolic arterial pressures were 11% from baseline after clonidine and dexmedetomidine. During operation, the maximum reduction in heart rate was 18% in the clonidine and dexmedetomidine groups compared with the placebo group. After operation, the maximum decrease in systolic arterial pressure was 11%, diastolic arterial pressure 15% and oxygen consumption 17% in the clonidine and dexmedetomidine groups compared with placebo. In summary, both clonidine 4 micrograms kg-1 and dexmedetomidine 2.5 micrograms kg-1 decreased perioperative oxygen consumption effectively, with a similar haemodynamic profile.
authors.affiliation: Department of Anaesthesiology, Turku University Hospital, Finland.
authors.forename: M T
authors.initials: MT
authors.lastname: Taittonen
authors.forename: O A
authors.initials: OA
authors.lastname: Kirvelä
authors.forename: R
authors.initials: R
authors.lastname: Aantaa
authors.forename: J H
authors.initials: JH
authors.lastname: Kanto
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000328:Adult; D000768:Anesthesia, General; D003000:Clonidine / Q000494:pharmacology*; D004311:Double-Blind Method; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D020926:Medetomidine; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D011292:Premedication; D013518:Surgery, Plastic; D013565:Sympatholytics / Q000494:pharmacology*
chemical_list: D000316:Adrenergic alpha-Agonists; D007093:Imidazoles; D013565:Sympatholytics; D003000:Clonidine; D020926:Medetomidine