title: Cardiovascular effects of dopamine hydrochloride and phenylephrine hydrochloride in healthy isoflurane-anesthetized New Zealand White rabbits (Oryctolagus cuniculus).
abstract: OBJECTIVE
  To determine the cardiopulmonary effects of progressively increasing infusion rates of dopamine hydrochloride and phenylephrine hydrochloride in healthy adult New Zealand White rabbits anesthetized with isoflurane.
  
  
  METHODS
  6 New Zealand White rabbits. (Oryctolagus cuniculus).
  
  
  METHODS
  Each rabbit was anesthetized on 2 occasions (≥ 2 weeks apart) with isoflurane in oxygen at 1.5 times the published isoflurane minimum alveolar concentration of 2.07%. Carotid artery and pulmonary artery catheters were placed. During each anesthetic episode, each rabbit received 5 progressively increasing doses of either dopamine (5, 10, 15, 20, or 30 μg/kg/min) or phenylephrine (0.125, 0.25, 0.5, 1.0, and 2.0 μg/kg/min). Blood gas and cardiopulmonary measurements were obtained after a 20-minute equilibration period prior to administration of the first drug dose (baseline) and after each subsequent dose administration.
  
  
  RESULTS
  Dopamine increased stroke index at the highest infusion rate of 30 μg/kg/min; however, cardiac output and mean arterial blood pressure remained unchanged from baseline values. Administration of phenylephrine at a rate of 2 μg/kg/min increased mean arterial blood pressure to 62 mm Hg from the baseline value of 45 mm Hg. This was a result of an increase in systemic vascular resistance with a concomitant decrease in heart rate and no change in cardiac output. Blood lactate concentration increased with time when rabbits received either treatment.
  
  
  CONCLUSIONS
  Within the dose range of 5 to 30 μg/kg/min, dopamine was not an effective treatment for isoflurane-induced hypotension in rabbits and phenylephrine was only minimally effective at a dose of 2 μg/kg/min.
authors: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.
authors: Jaclyn M
authors: JM
authors: Gosliga
authors: Linda S
authors: LS
authors: Barter
mesh_terms: D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002316:Cardiotonic Agents / Q000494:pharmacology*; D018592:Cross-Over Studies; D004298:Dopamine / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D007530:Isoflurane / Q000008:administration & dosage*; D010100:Oxygen / Q000097:blood; D010656:Phenylephrine / Q000494:pharmacology*; D011817:Rabbits; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D010656:Phenylephrine; D007530:Isoflurane; D010100:Oxygen; D004298:Dopamine