Perioperative stress response in the dog: effect of pre-emptive administration of medetomidine.
OBJECTIVE
To determine the effect of medetomidine on the stress response induced by ovariohysterectomy in isoflurane-anesthetized dogs.


METHODS
Prospective randomized study.


METHODS
Twelve healthy adult female purpose-bred dogs, weighing 16.8 to 25 kg.


METHODS
Two treatments were randomly administered to each of twelve dogs at weekly intervals: (1) Saline injected IM followed in 15 minutes by isoflurane anesthesia (ISO) induced by mask and maintained at an end-tidal concentration of 1.8% for 60 minutes; and (2) Medetomidine, 15 ug/lkg IM followed in 15 minutes by isoflurane anesthesia (ISO&MED) induced by mask and maintained at an end-tidal concentration of 1.0% for 60 minutes. One week after completion of these two treatments, all dogs were ovariohysterectomized. six receiving each treatment (SURG and SURG&MED). Central venous blood samples (10 mL) were obtained immediately before medetomidine or saline (baseline) and at 30, 75, and 195 minutes and 24 hours after administration of medetomidine or saline in ISO and ISO&MED. In SURG and SURG&MED, samples were obtained immediately prior to injection of medetomidine or saline (baseline) and at 30 (before skin incision), 45 (after severence of the ovarian ligament), 75 (after skin closure), 105 (30 minutes after skin closure, dog recovered and in sternal recumbency), 135, 195, 375 minutes, and 24 hours after the initial sample. Samples were analyzed for epinephrine, norepinephrine, adrenocorticotrophic hormone (ACTH), cortisol, insulin, and glucose. Data were analyzed by analysis of variance and where significant differences were found, a least significant difference test was applied.


RESULTS
Premedication with medetomidine prevented or delayed the stress response induced by ovariohysterectomy in isoflurane-anesthetized dogs.


CONCLUSIONS
The stress response induced by ovariohysterectomy, although significant, is of short duration. Medetomidine safely and effectively reduced surgically-induced stress responses.


CONCLUSIONS
Surgically induced stress responses can be obtunded or prevented by administration of medetomidine.
Benson
G J
GJ
Department of Veterinary Clinical Medicine, University of Illinois, Urbana 61802, USA.
Grubb
T L
TL
Neff-Davis
C
C
Olson
W A
WA
Thurmon
J C
JC
Lindner
D L
DL
Tranquilli
W J
WJ
Vanio
O
O
D000222:Adaptation, Physiological / Q000187:drug effects; D000324:Adrenocorticotropic Hormone / Q000097:blood; D018685:Anesthetics, Inhalation; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D004283:Dog Diseases / Q000097:blood / Q000517:prevention & control* / Q000601:surgery; D004285:Dogs; D004837:Epinephrine / Q000097:blood; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D006993:Hypnotics and Sedatives / Q000008:administration & dosage*; D007044:Hysterectomy / Q000009:adverse effects / Q000662:veterinary; D007273:Injections, Intramuscular / Q000662:veterinary; D007328:Insulin / Q000097:blood; D007530:Isoflurane; D020926:Medetomidine / Q000008:administration & dosage*; D009638:Norepinephrine / Q000097:blood; D010052:Ovariectomy / Q000009:adverse effects / Q000662:veterinary; D011292:Premedication / Q000662:veterinary; D011446:Prospective Studies; D013312:Stress, Physiological / Q000097:blood / Q000517:prevention & control / Q000662:veterinary*
D018685:Anesthetics, Inhalation; D001786:Blood Glucose; D006993:Hypnotics and Sedatives; D007328:Insulin; D000324:Adrenocorticotropic Hormone; D007530:Isoflurane; D020926:Medetomidine; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine