Objective—To compare the effects of pretreatment
with dexamethasone, physical stress (exercise), or
both on sedation and plasma hormone and glucose
concentrations in dogs treated with dexmedetomidine
Animals—6 healthy purpose-bred Beagles.
Procedure—Dogs received 4 treatments each in a
randomized order prior to IV administration of DEX (5
µg/kg). Pretreatments were as follows: (1) IV administration
of saline (0.9% NaCl) solution and no exercise
(control group); (2) IV administration of dexamethasone
(0.05 mg/kg) and no exercise (DM group);
(3) IV administration of saline solution and exercise
(EX group; 15 minutes of trotting on a treadmill at a
speed of 2 m/s); and 4) IV administration of dexamethasone
and exercise (DM+EX group).
Results—Following DEX administration, all dogs
had similar times to recumbency and sedation index
values, irrespective of pretreatment with dexamethasone
or exercise. Plasma catecholamine concentrations
decreased after DEX administration.
Compared with control group dogs, plasma cortisol
concentrations were higher in EX-group dogs prior
to DEX administration and lower in DM- and
DM+EX-group dogs following DEX administration.
Administration of DEX decreased plasma cortisol
concentration in EX-group dogs only. Plasma glucose
concentration was not influenced by exercise
or dexamethasone administration but was lower
than baseline concentrations at 30 minutes after
DEX administration and returned to baseline values
by 90 minutes. Heart and respiratory rates and rectal
temperature increased during exercise. After
DEX administration, these values decreased below
baseline values. The decrease in heart rate was of
shorter duration in dogs that underwent pretreatment
with dexamethasone, exercise, or both than
in control group dogs
Conclusions and Clinical Relevance—Pretreatment
with dexamethasone, moderate physical stress (exercise),
or both did not influence sedation or cause
adverse effects in healthy dogs treated with DEX.
(Am J Vet Res 2005;66:260–265)
Objective—To compare the perioperative stress
response in dogs administered medetomidine or acepromazine
as part of the preanesthetic medication.
Animals—42 client-owned dogs that underwent
Procedure—Each dog was randomly allocated to
receive medetomidine and butorphanol tartrate
(20 µg/kg and 0.2 mg/kg, respectively, IM) or acepromazine
maleate and butorphanol (0.05 and 0.2 mg/kg,
respectively, IM) for preanesthetic medication.
Approximately 80 minutes later, anesthesia was
induced by administration of propofol and maintained
by use of isoflurane in oxygen. Each dog was also
given carprofen before surgery and buprenorphine
after surgery. Plasma concentrations of epinephrine,
norepinephrine, cortisol, and β-endorphin were measured
at various stages during the perioperative period.
In addition, cardiovascular and clinical variables
Results—Concentrations of epinephrine, norepinephrine,
and cortisol were significantly lower for dogs
administered medetomidine. Concentrations of
β-endorphin did not differ between the 2 groups.
Heart rate was significantly lower and mean arterial
blood pressure significantly higher in dogs administered
medetomidine, compared with values for dogs
Conclusions and Clinical Relevance—Results indicate
that for preanesthetic medications, medetomidine
may offer some advantages over acepromazine
with respect to the ability to decrease perioperative
concentrations of stress-related hormones. In particular,
the ability to provide stable plasma catecholamine
concentrations may help to attenuate perioperative
activation of the sympathetic nervous system.
(Am J Vet Res 2002;63:969–975)
Objective—To identify variables and evaluate methods
for assessing chronic pain in dogs.
Animals—41 dogs with canine hip dysplasia (CHD),
and 24 apparently healthy dogs with no history of
Procedure—2 veterinarians evaluated the dogs' locomotion
and signs of pain. Owners of dogs with CHD
and control dogs answered a questionnaire regarding
their dogs' demeanor, behavior, and locomotion
(descriptive scales) and assessed pain and locomotion
(visual analog scales). Plasma concentrations of
several stress-related hormones were determined,
and 13 radiologic variables were assessed in affected
Results—For many of the questions, answers provided
by owners of dogs with CHD differed significantly
from those of owners of control dogs. Stress hormone
concentrations differed significantly between
dogs with CHD and controls, but individual variation
was too great for them to be of value in pain assessment.
None of the radiologic variables examined correlated
well with owner or veterinarian pain scores.
Conclusions and Clinical Relevance—Chronic pain
could be assessed in dogs with CHD through completion
of the study questionnaire by a person familiar
with the pet (eg, owner) after receiving appropriate
education in its use. Eleven variables were identified
as being potentially useful in assessment of chronic
pain in dogs. (J Am Vet Med Assoc 2003;222: