Objective—To evaluate the effects of ketamine, magnesium sulfate, and their combination on the minimum alveolar concentration (MAC) of isoflurane (ISO-MAC) in goats.
Animals—8 adult goats.
Procedures—Anesthesia was induced with isoflurane delivered via face mask. Goats were intubated and ventilated to maintain normocapnia. After an appropriate equilibration period, baseline MAC (MACB) was determined and the following 4 treatments were administered IV: saline (0.9% NaCl) solution (loading dose [LD], 30 mL/20 min; constant rate infusion [CRI], 60 mL/h), magnesium sulfate (LD, 50 mg/kg; CRI, 10 mg/kg/h), ketamine (LD, 1 mg/kg; CRI, 25 μg/kg/min), and magnesium sulfate (LD, 50 mg/kg; CRI, 10 mg/kg/h) combined with ketamine (LD, 1 mg/kg; CRI, 25 μg/kg/min); then MAC was redetermined.
Results—Ketamine significantly decreased ISOMAC by 28.7 ± 3.7%, and ketamine combined with magnesium sulfate significantly decreased ISOMAC by 21.1 ± 4.1%. Saline solution or magnesium sulfate alone did not significantly change ISOMAC.
Conclusions and Clinical Relevance—Ketamine and ketamine combined with magnesium sulfate, at doses used in the study, decreased the end-tidal isoflurane concentration needed to maintain anesthesia, verifying the clinical impression that ketamine decreases the end-tidal isoflurane concentration needed to maintain surgical anesthesia. Magnesium, at doses used in the study, did not decrease ISOMAC or augment ketamine's effects on ISOMAC.
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 evaluate the effect of MgSO4, alone and in combination with propofol, on the minimum alveolar concentration preventing motor movement (MACNM) in sevoflurane-anesthetized dogs.
ANIMALS 6 healthy purpose-bred adult male Beagles (least squares mean ± SEM body weight, 12.0 ± 1.1 kg).
PROCEDURES Dogs were anesthetized 3 times at weekly intervals. The MACNM was measured 45 minutes after induction of anesthesia (baseline; MACNM-B) and was determined each time by use of a noxious electrical stimulus. Treatments were administered as a loading dose and constant rate infusion (CRI) as follows: treatment 1, MgSO4 loading dose of 45 mg/kg and CRI of 15 mg/kg/h; treatment 2, propofol loading dose of 4 mg/kg and CRI of 9 mg/kg/h; and treatment 3, MgSO4 and propofol combination (same doses used previously for each drug). A mixed-model ANOVA and Tukey-Kramer tests were used to determine effects of each treatment on the percentage decrease from MACNM-B. Data were reported as least squares mean ± SEM values.
RESULTS Decrease from MACNM-B was 3.4 ± 3.1%, 48.3 ± 3.1%, and 50.3 ± 3.1%, for treatments 1, 2, and 3, respectively. The decrease for treatments 2 and 3 was significantly different from that for treatment 1; however, no significant difference existed between results for treatments 2 and 3.
CONCLUSIONS AND CLINICAL RELEVANCE MgSO4 did not affect MACNM, nor did it potentiate the effects of propofol on MACNM. Administration of MgSO4 in this study appeared to provide no clinical advantage as an anesthetic adjuvant.
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 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 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;
Objective—To determine proportions of cats in which
feline infectious peritonitis (FIP) was diagnosed on an
annual, monthly, and regional basis and identify
unique characteristics of cats with FIP.
Sample Population—Records of all feline accessions
to veterinary medical teaching hospitals (VMTH)
recorded in the Veterinary Medical Data Base
between January 1986 and December 1995 and of all
feline accessions for necropsy or histologic examination
at 4 veterinary diagnostic laboratories.
Procedure—Proportions of total and new feline
accessions for which a diagnosis of FIP was recorded
were calculated. To identify characteristics of cats
with FIP, cats with FIP were compared with the next
cat examined at the same institution (control cats).
Results—Approximately 1 of every 200 new feline
and 1 of every 300 total feline accessions at VMTH in
North America and approximately 1 of every 100
accessions at the diagnostic laboratories represented
cats with FIP. Cats with FIP were significantly more
likely to be young, purebred, and sexually intact males
and significantly less likely to be spayed females and
discharged alive than were control cats. The proportion
of new accessions for which a diagnosis of FIP
was recorded did not vary significantly among years,
months, or regions of the country.
Conclusions and Clinical Relevance—Results indicated
that FIP continues to be a clinically important
disease in North America and that sexually intact
male cats may be at increased risk, and spayed
females at reduced risk, for FIP. The high prevalence
of FIP and lack of effective treatment emphasizes the
importance of preventive programs, especially in catteries.
(J Am Vet Med Assoc 2001;218:1111–1115)
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
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.