Objective—To compare pharmacokinetic and pharmacodynamic
characteristics of fentanyl citrate after IV or
transdermal administration in cats.
Animals—6 healthy adult cats with a mean weight of
Procedure—Each cat was given fentanyl IV
(25 mg/cat; mean ± SD dosage, 7.19 ± 1.17 mg/kg
of body weight) and via a transdermal patch (25 µg
of fentanyl/h). Plasma concentrations of fentanyl
were measured by use of radioimmunoassay.
Pharmacokinetic analyses of plasma drug concentrations
were conducted, using an automated curvestripping
process followed by nonlinear, leastsquares
regression. Transdermal delivery of drug
was calculated by use of IV pharmacokinetic data.
Results—Plasma concentrations of fentanyl given IV
decreased rapidly (mean elimination half-life,
2.35 ± 0.57 hours). Mean ± SEM calculated rate of
transdermal delivery of fentanyl was 8.48 ± 1.7 mg/h
(< 36% of the theoretical 25 mg/h). Median steadystate
concentration of fentanyl 12 to 100 hours after
application of the transdermal patch was 1.58 ng/ml.
Plasma concentrations of fentanyl < 1.0 ng/ml were
detected in 4 of 6 cats 12 hours after patch application,
5 of 6 cats 18 and 24 hours after application,
and 6 of 6 cats 36 hours after application.
Conclusions and Clinical Relevance—In cats,
transdermal administration provides sustained plasma
concentrations of fentanyl citrate throughout a 5-
day period. Variation of plasma drug concentrations
with transdermal absorption for each cat was pronounced.
Transdermal administration of fentanyl has
potential for use in cats for long-term control of pain
after surgery or chronic pain associated with cancer.
(Am J Vet Res 2000;61:672–677)
Objective—To determine prevalence of radiographic
evidence of degenerative joint disease (DJD) in geriatric
Population—100 cats > 12 years of age.
Procedure—One investigator reviewed radiographs
and for each articulation (or group of articulations) that
was visible assigned a grade of severity (0, 1, 2, 3) for
DJD. Another investigator reviewed medical records
and recorded signalment, environment, previous disease,
diseases evident at time of radiography, FeLV
vaccination and infection status, feline immunodeficiency
virus serologic status, serum creatinine concentration,
serum globulin concentration, and any
other important findings. Associations between DJD
of grade 2 or 3 and variables recorded from the medical
record were determined.
Results—Radiographic evidence of DJD was evident
in 90% of cats. Neurologic disease was associated
with lesions in the lumbosacral portion of the vertebral
column. Severe lesions were found in 17% of the
elbow joints, but an underlying cause was not determined.
Conclusions and Clinical Relevance—Degenerative
joint disease was detected radiographically in most
geriatric cats and may be an overlooked cause of clinical
disease. Clinicians should be alert to the possibility
that DJD is associated with neurologic signs. (J
Am Vet Med Assoc 2002;220:628–632)
Objective—To document the signalment; history;
clinical signs; clinicopathologic, diagnostic imaging,
and surgical findings; perioperative complications;
and long-term clinical results of ameroid ring constrictor
(ARC) placement on single extrahepatic portosystemic
shunts (PSS) in cats.
Animals—23 cats treated with an ARC on a single
Procedure—An ARC was placed surgically around
the PSS. Portal pressure was measured prior to ARC
placement, with complete temporary PSS occlusion,
and after ARC placement. Cats were scheduled for
recheck transcolonic portal scintigraphy 8 to 10
weeks after surgery. Follow-up information was
obtained by telephone interview with the owners.
Results—An ARC was successfully placed in 22 of
23 cats. Intraoperative complications, consisting of
PSS hemorrhage, occurred in 2 cats. Mean (± SD)
portal pressure (n = 15) was 6.7 ± 2.9 mm Hg before
PSS manipulation, 18.6 ± 7.7 mm Hg with complete
temporary PSS occlusion, and 6.9 ± 2.7 mm Hg after
ARC placement. Postoperative complications developed
in 77% (17 of 22) of cats after ARC placement,
and included central blindness, hyperthermia, frantic
behavior, and generalized motor seizures.
Perioperative mortality rate was 4.3% (1 of 23).
Persistent shunting was identified in 8 of 14 cats.
Overall, 75% (15 of 20) of cats had an excellent longterm
Conclusions and Clinical Relevance—Placement of
an ARC on single extrahepatic PSS in cats resulted in
low surgical complication and perioperative mortality
rates, but most cats did have substantial postoperative
complications. Persistent shunting was common,
although many cats with persistent shunting were
clinically normal. (J Am Vet Med Assoc 2002;220: 1341–1347)
Objective—To determine outcome of medical and
surgical treatment in cats with ureteral calculi.
Procedure—Medical records were reviewed.
Owners and referring veterinarians were contacted
for follow-up information.
Results—All cats were initially treated medically before
a decision was made to perform surgery. Medical treatment
included parenteral administration of fluids and
diuretics to promote urine production and passage of
the ureteral calculus and supportive treatment for renal
failure. Ureteral calculi in the proximal portion of the
ureter were typically removed by ureterotomy, whereas
ureteral calculi in the distal portion of the ureter were
more likely to be removed by partial ureterectomy and
ureteroneocystostomy. Ureterotomy could be performed
without placement of a nephrostomy tube for
postoperative urine diversion. Postoperative complication
rate and perioperative mortality rate were 31% and
18%, respectively. The most common postoperative
complications were urine leakage and persistent ureteral
obstruction after surgery. Chronic renal failure was
common at the time of diagnosis and continued after
treatment, with serum creatinine concentration remaining
greater than the upper reference limit in approximately
half the cats. Twelve-month survival rates after
medical and surgical treatment were 66% and 91%,
respectively, with a number of cats dying of causes
related to urinary tract disorders, including ureteral calculus
recurrence and worsening of chronic renal failure.
Conclusions and Clinical Relevance—Results suggest
that medical and surgical management of ureteral
calculi in cats are associated with high morbidity
and mortality rates. Treatment can stabilize renal function,
although many surviving cats will continue to
have impaired renal function. (J Am Vet Med Assoc
Objective—To determine clinical, clinicopathologic,
radiographic, and ultrasonographic abnormalities in
cats with ureteral calculi.
Animals—163 client-owned cats.
Procedure—Medical records were reviewed, and
information on signalment, history, clinical signs, and
results of clinicopathologic testing and diagnostic
imaging was obtained.
Results—The number of cats in which ureterolithiasis
was diagnosed each year increased progressively during
the study period. Clinical signs tended to be nonspecific
and included inappetence, vomiting, lethargy,
and weight loss. A combination of survey radiography
and abdominal ultrasonography revealed ureteral calculi
in 66 of 73 (90%) cats in which the diagnosis was
confirmed at surgery or necropsy. Ultrasonography
revealed that ureteral calculi were causing ureteral
obstruction in 143 of 155 (92%) cats. One hundred
thirty-four of 162 (83%) cats had azotemia, 84 of 156
(54%) had hyperphosphatemia, and 22 of 152 (14%)
had hypercalcemia. Urinary tract infection was documented
in 10 of 119 (8%). Fifty-eight of 76 (76%) cats
with unilateral ureterolithiasis had azotemia and 33
(43%) had hyperphosphatemia, indicating impairment
of renal function in the contralateral kidney or prerenal
azotemia. Ultrasonographic imaging of the contralateral
kidney in cats with unilateral ureteral calculi suggested
that preexisting renal parenchymal disease
was common in cats with ureterolithiasis. Ninety-one
of 93 (98%) ureteral calculi contained calcium oxalate.
Conclusions and Clinical Relevance—Results suggest
that abdominal imaging should be performed in
all cats with chronic nonspecific signs or with acute
or chronic renal failure to rule out ureterolithiasis.
Preexisting renal disease may be common in cats
with ureteral calculi. (J Am Vet Med Assoc 2005;226:
Objective—To determine clinical outcome of permanent tracheostomy in cats with upper airway obstruction.
Design—Retrospective case series.
Procedures—Medical records were reviewed for information on history, signalment, clinical signs, results of preoperative clinicopathologic testing, cause of upper airway obstruction, surgical procedure, postoperative complications, and outcome.
Results—Causes of upper airway obstruction included neoplasia (squamous cell carcinoma [n = 6] or malignant lymphoma ), inflammatory laryngeal disease (5), laryngeal paralysis (4), trauma (3), and a laryngeal mass of unknown cause (1). Fourteen cats had dyspnea in the immediate postoperative period; dyspnea most often resulted from mucous plugs at the stoma or elsewhere in the respiratory tract. Eleven cats died, including 6 cats that died while hospitalized after surgery and 5 cats that died after discharge; 7 cats were eu-thanatized, most often because of progression of neoplasia; and 2 were still alive at the time of the study. The remaining cat was lost to follow-up after discharge from the hospital. Overall, median survival time for the 20 cats for which information was available was 20.5 days (range, 1 day to 5 years). Cats that underwent permanent tracheostomy because of inflammatory laryngeal disease were 6.61 times as likely to die as cats that underwent permanent tracheostomy for any other reason.
Conclusions and Clinical Relevance—Results indicated that permanent tracheostomy was an uncommon procedure in cats with upper airway obstruction that was associated with high complication and mortality rates.
Objective—To determine the items (question topics) for a subjective instrument to assess degenerative joint disease (DJD)–associated chronic pain in cats and determine the instrument design most appropriate for use by cat owners.
Animals—100 randomly selected client-owned cats from 6 months to 20 years old.
Procedures—Cats were evaluated to determine degree of radiographic DJD and signs of pain throughout the skeletal system. Two groups were identified: high DJD pain and low DJD pain. Owner-answered questions about activity and signs of pain were compared between the 2 groups to define items relating to chronic DJD pain. Interviews with 45 cat owners were performed to generate items. Fifty-three cat owners who had not been involved in any other part of the study, 19 veterinarians, and 2 statisticians assessed 6 preliminary instrument designs.
Results—22 cats were selected for each group; 19 important items were identified, resulting in 12 potential items for the instrument; and 3 additional items were identified from owner interviews. Owners and veterinarians selected a 5-point descriptive instrument design over 11-point or visual analogue scale formats.
Conclusions and Clinical Relevance—Behaviors relating to activity were substantially different between healthy cats and cats with signs of DJD-associated pain. Fifteen items were identified as being potentially useful, and the preferred instrument design was identified. This information could be used to construct an owner-based questionnaire to assess feline DJD-associated pain. Once validated, such a questionnaire would assist in evaluating potential analgesic treatments for these patients.
Objectives—To evaluate use of an ameroid ring constrictor
(ARC) for treatment for single extrahepatic portosystemic
shunts (PSSs) and identify factors associated
with postoperative death, continued portosystemic
shunting, and long-term outcome in dogs.
Animals—168 dogs with a single extrahepatic PSS.
Procedure—Medical records of dogs that had a single
extrahepatic PSS and were treated with an ARC
were reviewed. Signalment, history, clinical signs,
results of preoperative blood analyses and portal
pressure measurements, PSS location, ARC size,
postoperative complications, and postoperative
scintigraphy results were recorded. Owners were
interviewed 6 months to 6 years after surgery.
Results—Postoperative complications developed
in 10% of dogs. Postoperative mortality rate was
7.1%. Predictive factors for postoperative death
included high preoperative WBC count and postoperative
complications. Twenty-one percent of dogs
in which portal scintigraphy was performed 6 to 10
weeks after surgery had continued shunting.
Predictive factors for persistent shunting included
low preoperative plasma albumin concentration,
high portal pressure after complete occlusion, and
high portal pressure difference (postocclusion
minus baseline). Clinical outcome in 108 dogs was
classified as excellent (80%), good (14%), or poor
(6%). Predictive factors for excellent long-term clinical
outcome included high preoperative plasma
albumin concentration, low preoperative leukocytosis,
low portal pressure after complete occlusion,
absence of postoperative seizures, and absence of
Conclusions and Clinical Relevance—Use of an ARC
for treatment for a single extrahepatic PSS resulted in
low morbidity and mortality rates. Certain preoperative
factors were associated with increased risk of postoperative
death, continued portosystemic shunting, and
long-term outcome. (J Am Vet Med Assoc 2005;226: