title: Use of ephedrine and dopamine in dogs for the management of hypotension in routine clinical cases under isoflurane anesthesia.
abstract: OBJECTIVE
  To determine the cardiovascular responses of ephedrine and dopamine for the management of presurgical hypotension in anesthetized dogs.
  
  
  METHODS
  Prospective, randomized, clinical trial.
  
  
  METHODS
  Twelve healthy client-owned dogs admitted for orthopedic surgery; six per group
  
  
  METHODS
  Prior to surgery, 58 anesthetized dogs were monitored for hypotension [mean arterial pressure (MAP) <60 mmHg] that was not associated with bradycardia or excessive anesthetic depth. Ephedrine (0.2 mg kg(-1), IV) or dopamine (5 microg kg(-1) minute(-1), IV) was randomly assigned for treatment in 12 hypotensive dogs. Ten minutes after the first treatment (Tx(1)-10), ephedrine was repeated or the dopamine infusion rate was doubled. Cardiovascular assessments taken at baseline, Tx(1)-10, and 10 minutes following treatment adjustment (Tx(2)-10) were compared for differences within and between treatments (p < 0.05).
  
  
  RESULTS
  Ephedrine increased cardiac index (CI), stroke volume index (SVI), oxygen delivery index (DO(2)I), and decreased total peripheral resistance (TPR) by Tx(1)-10, while MAP increased transiently (<5 minutes). The second ephedrine bolus produced no further improvement. Dopamine failed to produce significant changes at 5 microg kg(-1) minute(-1), while 10 microg kg(-1) minute(-1) increased MAP, CI, SVI significantly from baseline, and DO(2)I compared with Tx(1)-10. The improvement in CI, SVI, and DO(2)I was not significantly different between treatments at Tx(2)-10.
  
  
  CONCLUSIONS
  In anesthetized hypotensive dogs, ephedrine and dopamine improved cardiac output and oxygen delivery. However, the pressure-elevating effect of ephedrine is transient, while an infusion of dopamine at 10 microg kg(-1) minute(-1) improved MAP significantly by additionally maintaining TPR.
authors.affiliation: Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
authors.forename: Hui C
authors.initials: HC
authors.lastname: Chen
authors.forename: Melissa D
authors.initials: MD
authors.lastname: Sinclair
authors.forename: Doris H
authors.initials: DH
authors.lastname: Dyson
mesh_terms: D000758:Anesthesia / Q000662:veterinary*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004283:Dog Diseases / Q000503:physiopathology / Q000517:prevention & control; D004285:Dogs / Q000502:physiology*; D004298:Dopamine / Q000008:administration & dosage / Q000494:pharmacology*; D004809:Ephedrine / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007022:Hypotension / Q000503:physiopathology / Q000517:prevention & control / Q000662:veterinary; D007262:Infusions, Intravenous / Q000662:veterinary; D007530:Isoflurane / Q000008:administration & dosage; D008297:Male; D011446:Prospective Studies; D016896:Treatment Outcome; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D014662:Vasoconstrictor Agents; D007530:Isoflurane; D004809:Ephedrine; D004298:Dopamine