Hemodynamic and sedative effects of dexmedetomidine in dog.
This study investigated hemodynamic and sedative effects of a single dose of the selective alpha-2 adrenoceptor agonist dexmedetoimidine (DMED) in isoflurane-anesthetized dogs. DMED (20 micrograms/kg i.v. 2-min infusion) was given to all dogs. In Group 1 the effects of DMED (time control; N = 10) were studied over 4 hr. In Group 2 (N = 11) glycopyrrolate (40 micrograms/kg initial dose followed by 20 micrograms/kg repeated every 30 min) was used to modulate the DMED-induced vagally mediated changes in heart rate. In Group 3 (N = 8), two doses of nifedipine were used to offset the DMED-induced increase in arterial blood pressure, low dose nifedipine = 10 micrograms/kg bolus followed by 2.5 micrograms/kg/min infusion for 20 min, high dose nifedipine = 20 micrograms/kg bolus followed by 5 micrograms/kg/min infusion for 20 min. DMED administration reduced isoflurane anesthetic requirements by 89% at 30 min and by 50% at 4 hr. Maximum increase in mean arterial blood pressure (MABP) +67 mm Hg occurred 1 min after DMED. MABP remained significantly elevated throughout the 4 hr studied (about +20%). Concomitant with the transient peak in MABP, heart rate (129 +/- 6 to 60 +/- 8 bpm) and cardiac output (3.5 +/- 0.3 to 0.9 +/- 0.1 l/min) decreased, whereas systemic vascular resistance (2460 +/- 210 to 14,700 +/- 1330 dynes.sec.cm-5) and left ventricular end diastolic pressure (4 +/- 1 to 27 +/- 4 mm Hg) increased.(ABSTRACT TRUNCATED AT 250 WORDS)
Bloor
B C
BC
UCLA School of Medicine.
Frankland
M
M
Alper
G
G
Raybould
D
D
Weitz
J
J
Shurtliff
M
M
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D004347:Drug Interactions; D006024:Glycopyrrolate / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects*; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D007530:Isoflurane / Q000378:metabolism; D008297:Male; D020926:Medetomidine; D009543:Nifedipine / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000378:metabolism; D013997:Time Factors
D000316:Adrenergic alpha-Agonists; D006993:Hypnotics and Sedatives; D007093:Imidazoles; D007530:Isoflurane; D009543:Nifedipine; D020926:Medetomidine; D006024:Glycopyrrolate