title: Effects of orally administered enalapril on blood pressure and hemodynamic response to vasopressors during isoflurane anesthesia in healthy dogs.
abstract: OBJECTIVE
  To examine whether preanesthetic administration of enalapril, compared with placebo, results in a greater decline in blood pressure (BP) or decreased responsiveness of BP to isotonic fluids or vasopressors in healthy dogs during isoflurane anesthesia.
  
  
  METHODS
  Randomized, experimental, placebo-controlled, blinded, crossover study.
  
  
  METHODS
  Twelve healthy, female, purpose-bred beagles.
  
  
  METHODS
  Dogs underwent the following week-long treatment protocols, each preceded by a 1 week washout period: oral placebo twice daily (PLA); oral enalapril, 0.5 mg kg(-1) twice daily, with the 15th dose withheld on the day of anesthesia (ENA-W), and oral enalapril, 0.5 mg kg(-1) twice daily, with the 15th dose administered 90 minutes prior to anesthetic induction (ENA). On day 8 of each treatment period, dogs were anesthetized in random order utilizing a standard protocol. Following stabilization at an end-tidal isoflurane concentration (Fe'Iso) of 1.3%, invasively measured systolic (SAP), diastolic (DAP) and mean (MAP) arterial blood pressure were continuously recorded via telemetry. Hypotension (SAP < 85 mmHg) was treated with the following sequential interventions: lactated Ringer's solution (LRS) bolus (10 mL kg(-1) ); repeated LRS bolus; dopamine (7 μg kg(-1)  min(-1) ); and dopamine (10 μg kg(-1)  min(-1) ) first without and then with vasopressin (1 mU kg(-1)  hour(-1) ).
  
  
  RESULTS
  Compared with the PLA but not the ENA-W group, the ENA group had significantly lower average SAP, DAP and MAP at an Fe'Iso of 1.3%, spent more minutes in hypotension, and required a greater number of interventions to correct moderate-to-severe mean arterial hypotension.
  
  
  CONCLUSIONS
  In healthy dogs, enalapril administered 90 minutes prior to isoflurane anesthesia increases the degree of intra-anesthetic hypotension and the number of interventions required to correct moderate-to-severe hypotension.
  
  
  CONCLUSIONS
  Dogs receiving angiotensin-converting enzyme inhibitors on the day of anesthesia may exhibit clinically significant intra-anesthetic hypotension.
authors: Department of Small Animal Medicine and Surgery, University of Georgia College of Veterinary Medicine, Athens, GA, USA.
authors: Amanda E
authors: AE
authors: Coleman
authors: MedVet Medical & Cancer Center for Pets of Chicago, Chicago, IL, USA.
authors: Molly K
authors: MK
authors: Shepard
authors: Department of Small Animal Medicine and Surgery, University of Georgia College of Veterinary Medicine, Athens, GA, USA.
authors: Chad W
authors: CW
authors: Schmiedt
authors: Department of Small Animal Medicine and Surgery, University of Georgia College of Veterinary Medicine, Athens, GA, USA.
authors: Erik H
authors: EH
authors: Hofmeister
authors: Department of Small Animal Medicine and Surgery, University of Georgia College of Veterinary Medicine, Athens, GA, USA.|Department of Physiology and Pharmacology, University of Georgia College of Veterinary Medicine, Athens, GA, USA.
authors: Scott A
authors: SA
authors: Brown
mesh_terms: D000284:Administration, Oral; D000777:Anesthetics / Q000008:administration & dosage*; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D018592:Cross-Over Studies; D004285:Dogs; D004656:Enalapril / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D007530:Isoflurane / Q000008:administration & dosage*; D011229:Preanesthetic Medication / Q000662:veterinary; D016037:Single-Blind Method; D014667:Vasopressins / Q000494:pharmacology
chemical_list: D000777:Anesthetics; D000959:Antihypertensive Agents; D014667:Vasopressins; D004656:Enalapril; D007530:Isoflurane
keywords: angiotensin-converting enzyme inhibitor; dog; enalapril; intraoperative hypotension; renin-angiotensin-aldosterone system