Use of volumetric capnography to identify pulmonary dysfunction in horses with and without clinically apparent recurrent airway obstruction

OBJECTIVE: To investigate whether volumetric capnography indices could be used to differentiate between horses without recurrent airway obstruction (RAO) and horses with RAO that were in clinical remission or that had clinically apparent RAO. ANIMALS: 70 adult Swiss Warmblood horses (20 used for pleasure riding and 50 used for dressage or show jumping). PROCEDURE: Horses were allocated to 4 groups on the basis of history, clinical signs, results of endoscopy, and cytologic findings (group 1, 21 healthy horses; group 2, 22 horses with RAO that were in remission; group 3, 16 horses with mild RAO; group 4, 11 horses with exacerbated RAO). Expiratory volume and CO2 curves were recorded by use of a computerized ultrasonic spirometer. Volumetric capnograms were plotted, and derived indices were calculated. RESULTS: Dead-space volume (VD) was calculated by use of the Bohr equation (VD(Bohr)) and for physiologic VD (VD(phys)). Ratios for VD(Bohr) to expiratory tidal volume (VT) and VD(phys) to V(T) as well as an index of effective CO2 elimination were significantly different among groups of horses. Age and use of the horses also significantly affected volumetric capnography indices. CONCLUSIONS AND CLINICAL RELEVANCE: Ratios of VD(Bohr) to VT and VD(phys) to VT as well as an index of effective CO2 elimination were sufficiently sensitive measures to distinguish between healthy horses and horses with RAO in remission. To optimize the ability of volumetric capnography indices to differentiate among horses in heterogeneous populations, it is important to account for effects of age and specific use of the horses.     

Facet joint geometry and intervertebral disk degeneration in the L5-S1 region of the vertebral column in German Shepherd dogs

OBJECTIVE: To evaluate the possible association between facet joint geometry and intervertebral disk degeneration in German Shepherd Dogs. ANIMALS: 25 German Shepherd Dogs and 11 control dogs of similar body weight and condition. PROCEDURE: Facet joint angles in the caudal portion of the lumbar region of the vertebral column (L5-S1) were measured by use of computed tomography, and the intervertebral discs were evaluated microscopically. The relationship between facet joint geometry and disk degeneration was evaluated by use of statistical methods. RESULTS: German Shepherd Dogs had significantly more facet joint tropism than control dogs, but an association with disk degeneration was not found. However, German Shepherd Dogs had a different facet joint conformation, with more sagittally oriented facet joints at L5-L6 and L6-L7 and a larger angle difference between the lumbar and lumbosacral facet joints, compared with control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: A large difference between facet joint angles at L6-L7 and L7-S1 in German Shepherd Dogs may be associated with the frequent occurrence of lumbosacral disk degeneration in this breed.     

Further contributions to the genetic aspect of congenital sensorineural deafness in Dalmatians

Sensorineural deafness is a common congenital disorder in Dalmatians and is genetically transmitted. Different modes of inheritance have been proposed and the objective of this study was to study these by segregation analyses using maximum likelihood procedures. Data from 33 complete Dalmatian families were collected and data from 56 single Dalmatians added. This resulted in a total of 575 dogs with 357 known phenotypes. All dogs were clinically evaluated and electrophysiologically tested with brainstem auditory evoked responses.The prevalence of deafness was 16.5% (9.4% unilaterally deaf, 7.1% bilaterally deaf). Females were 4.4% more affected than males but this difference was not significant. Within the same litter, different phenotypic expressions of deafness occurred, which suggested different expressions of the disease. In addition, two data sets were analysed: the first included normal, uni- and bilaterally deaf dogs, the second had normal and deaf Dalmatians. We found that a recessive allele at a single biallelic major locus fitted our data best, although an incomplete penetrance of the recessive homozygotes was observed.     

DOPPLER MEASUREMENT OF SPLANCHNIC BLOOD FLOW DURING DIGESTION IN UNSEDATED NORMAL DOGS

The purpose of this study was to measure splanchnic blood flow during digestion in unsedated dogs by using duplex Doppler sonography. The study population consisted of 12 healthy dogs. Blood flow in the cranial mesenteric artery, the celiac artery, and the aorta was measured before a test meal and at 20, 60, and 90 minutes after eating. The following measurements were made or calculated: vessel diameter, peak systolic velocity, end diastolic velocity, mean velocity, resistive index, pulsatility index, and flow volume. There was a significant postprandial decrease in the resistive and pulsatility indices in both the cranial mesenteric (preprandial RI = 0.867, postprandial RI = 0.796, preprandial PI = 3.033, postprandial PI = 2.173) and the celiac (preprandial RI = 0.854, postprandial RI = 0.769, preprandial PI = 2.639, postprandial PI = 1.930) arteries. In both vessels the end diastolic velocity, the mean velocity, and the flow volume increased significantly postprandially. These changes occurred significantly earlier in the celiac artery than in the cranial mesenteric artery. The findings most likely correspond to postprandial splanchnic vasodilation. Doppler ultrasound provide a good methode of detecting changes in postprandial splanchnic blood flow in the dog.     

Comparison of perioperative racemic methadone, levo-methadone and dextromoramide in cats using indicators of post-operative pain

OBJECTIVE: To compare three opioid agonist drugs for perioperative analgesia in cats. STUDY DESIGN: Prospective, blind, controlled, randomised trial. ANIMALS: Ninety client-owned cats, weighing 3.1 (2.1-4.5) kg, aged 14.6 (6.0-84.0) months, were studied. METHODS: Seventy-six cats, scheduled for ovariectomy, received either 0.6 mg kg(-1) racemic methadone, 0.3 mg kg(-1) levo-methadone, 0.05 mg kg(-1) dextromoramide or a saline placebo IM. Behaviour and body position were assessed and scored 20 minutes later by a single 'blinded' observer. Anaesthesia was induced with propofol and maintained with halothane. Heart rate (HR), respiratory rate (RR), Fe'CO2 and SpO2 were recorded during anaesthesia. Post-operatively, pain was categorised as absent, moderate or severe, on the basis of appearance, behaviour and response to palpation of the surgical wound (pain score). Appearance, pain scores and physiological variables were monitored every 30 minutes, for a duration of 4 hours. Differences between time-dependent continuous variables were analysed using mixed models for repeated measurements. Differences in categorical, time-dependent variables were analysed using chi2-tests. Significance was set at p < or = 0.05. RESULTS: There were no significant changes in appearance after pre-anaesthetic medication. After surgery, there was no association between appearance and pain score with HR or RR. The assessment of pain depended on comparison with the placebo group, by comparing animals' reactions to wound palpation. Sixteen of the 18 cats in the placebo group and 14 of the 19 cats in the dextromoramide group showed signs of moderate-to-severe pain after surgery. In the levo-methadone group (n = 20), one animal showed pain after 60 minutes and two after 120 minutes. One cat in the racemic methadone group (n = 19) showed pain signs and behavioural changes at 60 minutes. Compared to the two methadone groups, 'rescue' analgesia was required more often in cats treated with dextromoramide or saline. CONCLUSION AND CLINICAL RELEVANCE: Dextromoramide (0.05 mg kg(-1)) was ineffective, while racemic methadone (0.6 mg kg(-1)) and levo-methadone (0.3 mg kg(-1)) provided effective analgesia in cats following ovariectomy, without behavioural, respiratory or cardiovascular side effects.     

Nitric oxide metabolite production in the cranial cruciate ligament, synovial membrane, and articular cartilage of dogs with cranial cruciate ligament rupture

OBJECTIVE: To measure concentrations of nitric oxide metabolites (nitrite-nitrate [NOt]) in cartilage, synovial membrane, and cranial cruciate ligament (CCL) in dogs and evaluate associations with osteoarthritis in dogs with CCL rupture. ANIMALS: 46 dogs with CCL rupture and 54 control dogs without joint disease. PROCEDURE: Tissue specimens for histologic examination and explant culture were harvested during surgery in the CCL group or immediately after euthanasia in the control group; NOt concentrations were measured in supernatant of explant cultures and compared among dogs with various degrees of osteoarthritis and between dogs with and without CCL rupture. RESULTS: Osteoarthritic cartilage had significantly higher NOt concentration (1,171.6 nmol/g) than did healthy cartilage (491.0 nmol/g); NOt concentration was associated with severity of macroscopic and microscopic lesions. Synovial membrane NOt concentration did not differ between dogs with and without CCL rupture. Ruptured CCL produced less NOt than did intact ligaments. In control dogs, NOt concentrations were similar for intact ligaments (568.1 nmol/g) and articular cartilage (491.0 nmol/g). Synthesis of NOt was inhibited substantially by coincubation with inhibitors. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that NOt in canine joint tissues originates from the inducible nitric oxide synthase pathway. Nitric oxide metabolite production in cartilage was greater in dogs with osteoarthritis than in healthy dogs and was associated with lesion severity, suggesting that nitric oxide inhibitors may be considered as a treatment for osteoarthritis. The CCL produces substantial concentrations of NOt; the importance of this finding is unknown.     

Cardiomyopathy in Dystrophin-Deficient Hypertrophic Feline Muscular Dystrophy

A colony of cats affected with hypertrophic feline muscular dystrophy was used to study the occurrence of cardiomyopathy associated with dystrophin deficiency. Affected male and female cats, obligate carrier females, and unaffected healthy littermates were followed from 12 weeks of age into adulthood. Thoracic radiography, 2-D echocardiography, and 2-D-derived M-mode echocardiography were performed at 3-month intervals until 12 months of age and regularly thereafter. From 9 months of age, all affected cats had larger hearts than normal and carrier animals. Left ventricular wall thickness in systole and in diastole and interventricular septal thickness in systole were greater in affected cats 12 months and older when compared with normal or heterozygous animals (P < .05). The myocardium of affected cats was diffusely hypoechoic and thickened. Multiple hyperechoic foci were in the myocardium and papillary musculature. Shortening fraction was normal in all cats. Changes seen in carrier females included enlargement and hyperechogenicity of the papillary musculature after the age of 2 years. Gross and light microscopic examination revealed left ventricular wall thickening with multiple foci of mineralization in 2 of 5 hearts from dystrophin-deficient cats. Although approximately 10% of the normal dystrophin amount was present in the skeletal muscle, dystrophin could not be detected in the myocardium. Early onset concentric myocardial hypertrophy was present in all adult cats. Lesions were mainly localized in the myocardium of the left ventricular free wall and interventricular septum, papillary musculature, and the endocardium. Clinical signs of heart failure developed only infrequently in cats with hypertrophic feline muscular dystrophy.     

Determination of Normal Values Using an Automated Coagulation Timer for Activated Coagulation Time and its Application in Dogs with Hemophilia

The present study was performed to determine normal values for the Medtronic HemoTec automated activated coagulation time (ACT) analyzer (Medtronic HemoTec Inc, Parker, CO, distributed in Switzerland by Convergenza AG, Vaduz, Liechtenstein), and to evaluate its ability to detect dogs with hemophilia. ACT was measured in 43 healthy dogs presented to the Companion Animal Hospital, University of Bern, Bern, Switzerland, with the Medtronic HemoTec ACT analyzer to determine normal values. The mean +/- 2 standard deviations (SDs) of the values obtained was defined as the normal range. ACT was measured 8-10 times on the same day in 6 dogs to determine repeatability. ACT also was measured in 11 dogs with hemophilia and compared with a conventional visual ACT measurement test and with the activated partial thromboplastin time (APTT). ACT values of the 43 dogs used to determine normal values ranged from 66.5 to 97.0 seconds (mean, 79.3 seconds; SD, 7.35 seconds; median, 78.5 seconds). A range of 64-95 seconds (mean +/- 2 SDs) was defined as the normal range for the tested device. Repeatability was poor (r = 0.256). ACT values measured with the automated device did not correlate with ACT values measured with a conventional visual test or with APTT Sensitivity of the test was 90.9%, specificity was 98.0%, and accuracy was 96.7%. Variability in the test results was large and may lead to incorrect results. The automated measurement device was not superior to the conventional visual method in evaluating dogs with hemophilia.     

STAGING OF LUMBAR INTER VERTEBRAL DISC DEGENERATION IN NONCHONDRODYSTROPHIC DOGS USING LOW-FIELD MAGNETIC RESONANCE IMAGING

Recognition of disc degeneration in vivo is important in the investigation of the pathophysiology of intervertebral disc disease as well as the assessment of patients. The purpose of this study was to compare low-field magnetic resonance imaging and histopathologic findings of disc degeneration in the canine caudal lumbar spine. A simple four-stage classification system for disc degeneration is proposed. Most common signs of disc degeneration in magnetic resonance imaging included nuclear clefts, decreased signal intensity of the nucleus pulposus and tears of the annulus fibrosus, or disc herniations. The association between magnetic resonance images and histopathologic findings was highly significant. A sensitivity of 100% and specificity of 79% for magnetic resonance imaging was calculated using histopathology as the gold standard.