Objective—To evaluate the effect of IV administration of tramadol hydrochloride on the minimum alveolar concentration of isoflurane (ISOMAC) that prevented purposeful movement of rabbits in response to a noxious stimulus.
Animals—Six 6- to 12-month-old female New Zealand White rabbits.
Procedures—Anesthesia was induced and maintained with isoflurane in oxygen. A baseline ISOMAC was determined by clamping a pedal digit with sponge forceps until gross purposeful movement was detected or a period of 60 seconds elapsed. Subsequently, tramadol (4.4 mg/kg) was administered IV and the posttreatment ISOMAC (ISOMACT) was measured.
Results—Mean ± SD ISOMAC and ISOMACT values were 2.33 ± 0.13% and 2.12 ± 0.17%, respectively. The ISOMAC value decreased by 9 ± 4% after tramadol was administered. Plasma tramadol and its major metabolite (M1) concentrations at the time of ISOMACT determination varied widely (ranges, 181 to 636 ng/mL and 32 to 61 ng/mL, respectively). Intervals to determination of ISOMACT and plasma tramadol and M1 concentrations were not correlated with percentage change in the ISOMAC. Heart rate decreased significantly immediately after tramadol administration but by 10 minutes afterward was not different from the pretreatment value. Systolic arterial blood pressure decreased to approximately 60 mm Hg for approximately 5 minutes in 3 rabbits after tramadol administration. No adverse effects were detected.
Conclusions and Clinical Relevance—As administered, tramadol had a significant but clinically unimportant effect on the ISOMAC in rabbits. Higher doses of tramadol may provide clinically important reductions but may result in a greater degree of cardiovascular depression.
Objective—To investigate the effects of the concurrent administration of 70% N2O on the minimum alveolar concentration (MAC) for sevoflurane in dogs, the MAC derivative that blocks motor movement (MACNM), and the MAC derivative that blocks autonomic responses (MACBAR).
Animals—7 adult sexually intact male mixed-breed dogs.
Procedures—For each dog, anesthesia was induced with sevoflurane delivered via a face mask. Initially, the baseline MAC, MACNM, and MACBAR for sevoflurane were determined by use of a noxious stimulus (50 V, 50 Hz, and 10 milliseconds) applied subcutaneously over a midulnar region. Nitrous oxide (70%) was added to the breathing circuit, and MAC, MACNM, and MACBAR were determined again. Percentage changes from the respective baseline concentrations for MAC, MACNM’ and MACBAR were calculated after the administration of N2O.
Results—Baseline median values for the MAC, MACNM, and MACBAR for sevoflurane were 1.75%, 2.00%, and 2.50%, respectively. Addition of 70% N2O significantly decreased MAC, MACNM, and MACBAR by 24.4%, 25.0%, and 35.2%, respectively, and these values did not differ significantly from each other.
Conclusions and Clinical Relevance—Supplementation with 70% N2O caused a clinically important and significant decrease in the MAC, MACNM’ and MACBAR for sevoflurane in dogs.
Objective—To determine the effectiveness of preinduction hyperbaric oxygen treatment (HBOT) in ameliorating signs of experimentally induced endotoxemia in horses.
Animals—18 healthy adult horses.
Procedures—Horses were randomly assigned to 1 of 3 equal-sized treatment groups to receive normobaric ambient air and lipopolysaccharide (LPS), HBOT and LPS, or HBOT and physiologic saline (0.9% NaCl) solution. Horses were physically examined, and blood was obtained for a CBC and to determine concentration or activity of plasma tissue necrosis factor-α, blood lactate, and blood glucose before the horses were treated with HBOT and then intermittently for 6 hours after administration of LPS or physiologic saline solution.
Results—All LPS-treated horses developed signs and biochemical and hematologic changes consistent with endotoxemia. Treatment with HBOT significantly ameliorated the effect of LPS on clinical endotoxemia score but did not significantly improve other abnormalities associated with endotoxemia.
Conclusions and Clinical Relevance—The protective effect of HBOT was minimal, and results did not support its use as a treatment for horses prior to development of endotoxemia.
Objective—To use an inverse dynamics method to describe the motion of the canine pelvic limb in 3 dimensions.
Animals—6 healthy adult dogs.
Procedures—For each dog, 16 anatomic and tracking markers were used to define the center of rotation for the pelvic limb joints and a kinematic model was created to describe the motion of the pelvic limb. Kinetic, kinematic, and morphometric data were combined so that an inverse dynamics method could be used to define angular displacement, joint moment, and power of the hip, stifle, and tibiotarsal (hock) joints in the sagittal, frontal, and transverse planes.
Results—Movement and energy patterns were described for the hip, stifle, and hock joints in the sagittal, frontal, and transverse planes.
Conclusions and Clinical Relevance—Knowledge of the 3-D movement of the pelvic limb can be used to better understand its motion, moment, and energy patterns in healthy dogs and provide a referent with which gaits of dogs with pelvic limb injuries before and after surgical repair or rehabilitation can be compared and characterized. This information can then be used to guide decisions regarding treatment options for dogs with pelvic limb injuries.
Objective—To compare the 3-D motion of the pelvic limb among clinically normal dogs and dogs with cranial cruciate ligament (CCL)–deficient stifle joints following tibial plateau leveling osteotomy (TPLO) or lateral fabellar–tibial suture (LFS) stabilization by use of an inverse dynamics method.
Animals—6 clinically normal dogs and 19 dogs with CCL-deficient stifle joints that had undergone TPLO (n = 13) or LFS (6) stabilization at a mean of 4 and 8 years, respectively, prior to evaluation.
Procedures—For all dogs, an inverse dynamics method was used to describe the motion of the pelvic limbs in the sagittal, frontal, and transverse planes. Motion and energy patterns for the hip, stifle, and tibiotarsal (hock) joints in all 3 planes were compared among the 3 groups.
Results—Compared with corresponding variables for clinically normal dogs, the hip joint was more extended at the beginning of the stance phase in the sagittal plane for dogs that had a TPLO performed and the maximum power across the stifle joint in the frontal plane was greater for dogs that had an LFS procedure performed. Otherwise, variables in all planes were similar among the 3 groups.
Conclusions and Clinical Relevance—Gait characteristics of the pelvic limb did not differ between dogs that underwent TPLO and dogs that underwent an LFS procedure for CCL repair and were similar to those of clinically normal dogs. Both TPLO and LFS successfully provided long-term stabilization of CCL-deficient stifle joints of dogs with minimal alterations in gait.
Objective—To compare prevalence of organisms and
histologic changes in eyes from dogs with blastomycosis
that were either untreated or undergoing treatment
Animals—36 dogs with endophthalmitis associated
Procedure—Signalment, results of ophthalmic examination,
and duration of treatment with itraconazole
were extracted from medical records. Histologic sections
from eyes were examined for prevalence and
viability (ie, budding) of fungal organisms. A scoring
system was devised to assess the degree of inflammation.
Results—Clinically, all eyes were blind and had signs
of severe endophthalmitis. Histologically, the type
and degree of inflammation and prevalence of
Blastomyces dermatitidis were not significantly different
between dogs treated with itraconazole and
untreated dogs or among groups of dogs treated for
different time periods (4 to 14, 15 to 28, or 29 to 72
days). Replication of the organisms in vascular tissues
as well as avascular spaces in the eyes was similar in
treated and untreated dogs. Lens rupture was seen in
12 of 29 (41%) eyes.
Conclusions and Clinical Relevance—Persistence
of inflammation in eyes of dogs with naturally occurring
blastomycosis is likely attributable to the continued
presence of B dermatitidis, regardless of the
duration of treatment with itraconazole. Lens capsule
rupture, a common and previously unreported histologic
finding, may contribute to cataract formation and
continued inflammation. (J Am Vet Med Assoc 2004;
Animals—95 mares with a cytologic diagnosis of persistent endometritis.
Procedures—Mares were treated with P acnes or placebo (both administered IV) on days 0, 2, and 6. No attempt was made to alter additional treatments administered by attending veterinarians. Information on breeding history, physical examination findings, results of cytologic examination and microbial culture of uterine samples, additional treatments administered, breeding dates, results of pregnancy examinations, whether a live foal was produced, and reactions to treatment was recorded.
Results—In multivariate logistic regression models, mare age, year of entry into the study, and first breeding within 8 days after first treatment with P acnes or placebo were significantly associated with pregnancy. Fewer number of cycles bred and younger age were significantly associated with delivery of a live foal in a separate multivariate analysis. Results of multivariate logistic regression modeling indicated that mares treated with P acnes were more likely to become pregnant and to deliver a live foal, compared with placebo-treated controls.
Conclusions and Clinical Relevance—IV administration of P acnes as an adjunct to conventional treatments in mares with a cytologic diagnosis of persistent endometritis improved pregnancy and live foal rates. The optimal effect was detected in mares bred during the interval extending from 2 days before to 8 days after first treatment with P acnes.
Objective—To determine whether resistance to oxacillin and other antimicrobials in 3 Staphylococcus spp commonly isolated from dogs increased from 2001 to 2005.
Design—Retrospective case series.
Sample Population—1,772 clinical samples of various types obtained from dogs examined at the University of Tennessee Veterinary Teaching Hospital or at regional veterinary hospitals and submitted to the bacteriology and mycology laboratories associated with the teaching hospital.
Procedures—Samples were submitted by attending veterinarians to the bacteriology and mycology laboratories for routine aerobic microbial culture. Identification and antimicrobial susceptibility procedures were performed on all isolates. Susceptibility reports for each antimicrobial and Staphylococcus spp were determined from aggregate electronically archived test results. Oxacillin and multidrug resistance for Staphylococcus intermedius was analyzed by reviewing disk diffusion zone measurements.
Results—Oxacillin resistance increased among S intermedius isolates during the past 5 years, and the increase was associated with multidrug resistance. In 2005, 1 in 5 Staphylococcus spp isolates from canine clinical samples was resistant to oxacillin. The most common staphylococcal species isolated were S intermedius (n = 37), Staphylococcus schleiferi (21), and Staphylococcus aureus (4), and frequencies of oxacillin resistance in isolates of these species were 15.6%, 46.6%, and 23.5%, respectively.
Conclusions and Clinical Relevance—Veterinarians should be aware of the potential for empiric drug treatment failures in instances where Staphylococcus spp infections are common (eg, pyoderma). Judicious use of bacterial culture and susceptibility testing is recommended.
Objective—To evaluate clinical characteristics and breeds affected with bacterial keratitis and compare patterns of resistance in bacterial isolates over time in dogs.
Design—Retrospective cross-sectional study.
Animals—97 dogs with bacterial keratitis.
Procedure—Dogs with bacterial keratitis were identified from teaching hospital medical records at the Universities of Tennessee and Florida during the years 1993 to 2003. Data were collected pertaining to breed, Schirmer tear test results, treatments administered at the time of initial examination, bacterial species isolated, and resistance to selected antimicrobials.
Results—66% of the dogs were brachycephalic, 54% had tear production < 15 mm/min, and 29% were receiving a corticosteroid at the time of initial examination. The most common bacteria isolated were Staphylococcus intermedius (29%), β-hemolytic Streptococcus spp (17%), and Pseudomonas aeruginosa (21%). Staphylococcus intermedius isolates had limited resistance to certain antimicrobials. More than 80% of β-hemolytic Streptococcus spp isolates were resistant to neomycin, polymyxin B, and tobramycin. Isolates of P aeruginosa were susceptible to tobramycin and gentamicin and had limited resistance to ciprofloxacin and enrofloxacin. Among bacterial species isolated, there was no evidence of development of antimicrobial resistance over time.
Conclusions and Clinical Relevance—Data suggested that administration of ciprofloxacin or a combination of a first-generation cephalosporin and tobramycin may be used in the treatment of bacterial keratitis while awaiting results of bacterial culture and susceptibility testing. Evidence suggests that current methods of medical management of bacterial keratitis are not associated with increased antimicrobial resistance.
Objective—To characterize rib, intrathoracic, and concurrent
orthopedic injuries, and prognosis associated
with traumatic rib fracture in cats.
Procedure—Medical records from January 1980 to
August 1998 were examined for cats with traumatic
rib fracture. Signalment, cause of trauma, interval
from trauma to evaluation at a veterinary teaching
hospital, referral status and date, method of diagnosis,
duration of hospitalization, number and location of
rib fractures, presence of flail chest, costal cartilage
involvement, intrathoracic and concurrent orthopedic
injury, and clinical outcome were reviewed.
Results—Median age was 3 years. Twenty-five
(58%) cats with reported cause of trauma were
injured by interaction with another animal. Fortyseven
(78%) cats that were treated survived. Cats
that died had a median duration of hospitalization of
< 1 day. Ten (13%) cats had flail chest. Sixty-five
(87%) cats had intrathoracic injury (median, 2
injuries). Nine (100%) cats without detected intrathoracic
injury that were treated survived. Thirty-five
(47%) cats had concurrent orthopedic injury. Cats
with flail chest, pleural effusion, or diaphragmatic
hernia were significantly more likely to die than cats
without each injury.
Conclusions and Clinical Relevance—Traumatic rib
fracture in cats is associated with intrathoracic and
concurrent orthopedic injury. Aggressive treatment of
cats with traumatic rib fracture is warranted, because
the prognosis is generally favorable. Diagnosis and
treatment of intrathoracic injury associated with traumatic
rib fracture in cats should precede management
of concurrent orthopedic injury. ( J Am Vet Med