Cardiopulmonary evaluation of the use of medetomidine hydrochloride in cats.
OBJECTIVE
To evaluate the cardiovascular effects of the alpha2-adrenergic receptor agonist medetomidine hydrochloride in clinically normal cats.


METHODS
7 clinically normal cats.


METHODS
Cats were anesthetized with isoflurane, and thermodilution catheters were placed for measurement of central venous, pulmonary, and pulmonary capillary wedge pressures and for determination of cardiac output. The dorsal pedal artery was catheterized for measurement of arterial blood pressures and blood gas tensions. Baseline variables were recorded, and medetomidine (20 microg/kg of body weight, IM) was administered. Hemodynamic measurements were repeated 15 and 30 minutes after medetomidine administration.


RESULTS
Heart rate, cardiac index, stroke index, rate-pressure product, and right and left ventricular stroke work index significantly decreased from baseline after medetomidine administration, whereas systemic vascular resistance and central venous pressure increased. However, systolic, mean, and diastolic arterial pressures as well as arterial pH, and oxygen and carbon dioxide tensions were not significantly different from baseline values.


CONCLUSIONS
When administered alone to clinically normal cats, medetomidine (20 microg/kg, IM) induced a significant decrease in cardiac output, stroke volume, and heart rate. Arterial blood pressures did not increase, which may reflect a predominant central alpha2-adrenergic effect over peripheral vascular effects.
Lamont
L A
LA
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana 61801, USA.
Bulmer
B J
BJ
Grimm
K A
KA
Tranquilli
W J
WJ
Sisson
D D
DD
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002415:Cats / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007530:Isoflurane / Q000008:administration & dosage; D008297:Male; D020926:Medetomidine / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D018685:Anesthetics, Inhalation; D007530:Isoflurane; D020926:Medetomidine