title: Hemodynamic effects of dexmedetomidine in isoflurane-anesthetized cats.
abstract: OBJECTIVE
  To characterize the hemodynamic effects of dexmedetomidine in isoflurane-anesthetized cats.
  
  
  METHODS
  Prospective experimental study.
  
  
  METHODS
  Six healthy adult female cats weighing 4.6 ± 0.8 kg.
  
  
  METHODS
  Dexmedetomidine was administered intravenously using target-controlled infusions to maintain nine plasma concentrations between 0 and 20 ng mL(-1) in isoflurane-anesthetized cats. The isoflurane concentration was adjusted for each dexmedetomidine concentration to maintain the equivalent of 1.25 times the minimum alveolar concentration, based on a previous study. Heart rate, systemic and pulmonary arterial pressures, central venous pressure, pulmonary artery occlusion pressure, body temperature, and cardiac output were measured at each target plasma dexmedetomidine concentration. Additional variables were calculated. Arterial and mixed-venous blood samples were collected for blood gas, pH, and (on arterial blood only) electrolyte, glucose and lactate analysis. Plasma dexmedetomidine concentration was determined for each target. Pharmacodynamic models were fitted to the data.
  
  
  RESULTS
  Heart rate, arterial pH, arterial bicarbonate concentration, mixed-venous PO(2) , mixed-venous pH, mixed-venous hemoglobin oxygen saturation, cardiac index, stroke index, and venous admixture decreased following dexmedetomidine administration. Arterial blood pressure, central venous pressure, pulmonary arterial pressure, pulmonary arterial occlusion pressure, packed cell volume, PaO(2) , PaCO(2) , arterial hemoglobin concentration, mixed-venous PCO(2) , mixed-venous hemoglobin concentration, ionized calcium concentration, glucose concentration, rate-pressure product, systemic and pulmonary vascular resistance indices, left ventricular stroke work index, arterial oxygen concentration, and oxygen extraction increased following dexmedetomidine administration. Most variables changed in a dexmedetomidine concentration-dependent manner.
  
  
  CONCLUSIONS
  The use of dexmedetomidine as an anesthetic adjunct is expected to produce greater negative hemodynamic effects than a higher, equipotent concentration of isoflurane alone.
authors: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA. bhpypendop@ucdavis.edu
authors: Bruno H
authors: BH
authors: Pypendop
authors: Linda S
authors: LS
authors: Barter
authors: Scott D
authors: SD
authors: Stanley
authors: Jan E
authors: JE
authors: Ilkiw
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D000769:Anesthesia, Inhalation / Q000662:veterinary*; D018685:Anesthetics, Inhalation; D000818:Animals; D002415:Cats / Q000097:blood / Q000601:surgery*; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D007262:Infusions, Intravenous / Q000662:veterinary; D007530:Isoflurane; D016018:Least-Squares Analysis; D011446:Prospective Studies
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D018685:Anesthetics, Inhalation; D020927:Dexmedetomidine; D007530:Isoflurane