title: Beneficial effects of dexmedetomidine on ischaemic myocardium of anaesthetized dogs.
abstract: We have studied the effect of dexmedetomidine during coronary artery stenosis (CAS) in dogs. Three periods of 15 min of CAS were induced at 40-min intervals in two groups of dogs (dexmedetomidine compared with placebo). Dexmedetomidine was administered before the second and third periods of CAS in doses of 1 and 3 micrograms kg-1, respectively. Dexmedetomidine decreased plasma concentrations of noradrenaline by mean 71 (SEM 9)%, heart rate by 8 (4)%, cardiac output by 30 (6)% and increased mean arterial pressure by 23 (10)%. Dexmedetomidine reduced blood flow in non-ischaemic myocardium and in the ischaemic epicardial layer by 16 (8)%, but blood flow was preserved in the ischaemic mid-myocardial and subendocardial layers. Consequently, dexmedetomidine increased the ischaemic-non-ischaemic blood flow ratio. Dexmedetomidine did not change myocardial oxygen consumption but decreased myocardial oxygen demand from 4.91 (0.33) to 3.76 (0.25) mumol min-1 g-1, thereby reducing the oxygen deficiency of the ischaemic myocardium from 1.47 (0.37) to 0.29 (0.32) mumol min-1 g-1.
authors.affiliation: Department of Anaesthesiology, University Hospital of Maastricht, Netherlands.
authors.forename: P M
authors.initials: PM
authors.lastname: Roekaerts
authors.forename: F W
authors.initials: FW
authors.lastname: Prinzen
authors.forename: S
authors.initials: S
authors.lastname: De Lange
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000627:therapeutic use*; D000768:Anesthesia, General; D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D004285:Dogs; D006439:Hemodynamics / Q000187:drug effects; D007093:Imidazoles / Q000627:therapeutic use*; D007431:Intraoperative Complications / Q000188:drug therapy*; D020926:Medetomidine; D017202:Myocardial Ischemia / Q000188:drug therapy*
chemical_list: D000316:Adrenergic alpha-Agonists; D007093:Imidazoles; D020926:Medetomidine