title: Oral dexmedetomidine attenuates hemodynamic responses during emergence from general anesthesia in chronically instrumented dogs.
abstract: This investigation evaluated the hemodynamic effects of orally administered dexmedetomidine in chronically instrumented dogs in the conscious state, during enflurane anesthesia, and after emergence. Four experimental groups (n = 9 each) were completed. In groups 1 and 2, dexmedetomidine (10 or 20 micrograms/kg, respectively) was administered orally, and hemodynamics, arterial blood gas tensions, and plasma norepinephrine concentrations were monitored for 6 h. Animals in groups 3 and 4 were given dexmedetomidine (20 micrograms/kg) or placebo orally, and hemodynamics, arterial blood gas tensions, and plasma norepinephrine concentrations were measured 1 h later with animals in the conscious state, after 30 min of enflurane anesthesia (1.0 MAC), and 2 and 7 min after extubation. Oral administration of dexmedetomidine resulted in sedation with significant decreases in heart rate (76 +/- 4 to 49 +/- 4 beats per min), rate-pressure product (11,500 +/- 650 to 6,100 +/- 600 mmHg. beats per min), cardiac output (2.2 +/- 0.2 to 1.2 +/- 0.4 l/min), and plasma norepinephrine concentrations (290 +/- 50 to 135 pg/ml). Peak effects occurred within 30 min and lasted approximately 3 h. No reduction in coronary blood flow velocity, decrease in regional contractile function, or respiratory depression was observed. Administration of dexmedetomidine before enflurane anesthesia also was associated with a reduction in heart rate and rate-pressure product, and dexmedetomidine prevented the increase in heart rate (146 +/- 9 vs. 60 +/- 7 beats per min) and arterial pressure (117 +/- 7 vs. 98 +/- 7 mmHg) during emergence from anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226.
authors.forename: L T
authors.initials: LT
authors.lastname: Proctor
authors.forename: W T
authors.initials: WT
authors.lastname: Schmeling
authors.forename: D
authors.initials: D
authors.lastname: Roerig
authors.forename: J P
authors.initials: JP
authors.lastname: Kampine
authors.forename: D C
authors.initials: DC
authors.lastname: Warltier
mesh_terms: D000284:Administration, Oral; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000768:Anesthesia, General; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D020926:Medetomidine; D012119:Respiration / Q000187:drug effects
chemical_list: D000316:Adrenergic alpha-Agonists; D007093:Imidazoles; D020926:Medetomidine