Gabrielle Monteith

Outcome of medical and surgical treatment in dogs with cervical spondylomyelopathy : 104 cases (1988-2004)

OBJECTIVE To compare outcomes and survival times for dogs with cervical spondylomyelopathy (CSM; wobbler syndrome) treated medically or surgically. DESIGN Retrospective case series. ANIMALS 104 dogs. PROCEDURES Medical records of dogs were included if the diagnosis of CSM had been made on the basis of results of diagnostic imaging and follow-up information (minimum, 6 months) was available. Ordinal logistic regression was used to compare outcomes and the product-limit method was used to compare survival times between dogs treated surgically and dogs treated medically. RESULTS 37 dogs were treated surgically, and 67 were treated medically. Owners reported that 30 (81%) dogs treated surgically were improved, 1 (3%) was unchanged, and 6 (16%) were worse and that 36 (54%) dogs treated medically were improved, 18 (27%) were unchanged, and 13 (19%) were worse. Outcome was not significantly different between groups. Information on survival time was available for 33 dogs treated surgically and 43 dogs treated medically. Forty of the 76 (53%) dogs were euthanized because of CSM. Median and mean survival times were 36 and 48 months, respectively, for dogs treated medically and 36 and 46.5 months, respectively, for dogs treated surgically. Survival times did not differ significantly between groups. CONCLUSIONS AND CLINICAL RELEVANCE In the present study, neither outcome nor survival time was significantly different between dogs with CSM treated medically and dogs treated surgically, suggesting that medical treatment is a viable and valuable option for management of dogs with CSM.

The effect of the combination of locking screws and non-locking screws on the torsional properties of a locking-plate construct.

Little is known about the torsional properties of bone-plate constructs when a combination of locking and non-locking screws have been used. Sixty cadaveric canine femurs were divided into three groups. In the first group, the plate was affixed using three non-locking screws. In the second group, only locking screws were used while a combination of one locking and two non-locking screws were used in the third group. All constructs were subjected to torsion until failure. Torque, angle of torsion, and work were all calculated at the maximum failure point, as well as at five degrees of plastic deformation, which was thought to be more representative of clinical failure. At the maximum failure point, the locking group had significantly higher torque, angle, and work values than the non-locking group. The combination group was intermediate to the two other groups, and significantly differed from the non-locking group in torque, and from the locking group in work. At five degrees of plastic deformation, the locking group required significantly higher torque and work than the non-locking group. The combination group required a significantly higher torque than the non-locking group. This study suggests that a construct composed of all locking screws will fail at a greater torque value, and sustain greater work to failure in torsion compared to a construct composed of all non-locking screws. The addition of a single locking screw to an otherwise non-locking construct will increase the torque at the offset failure point and may be of clinical value in constructs subjected to high torsional loads.

Prospective multicenter evaluation of coagulation abnormalities in dogs following severe acute trauma

OBJECTIVES To describe coagulation abnormalities in dogs following severe acute trauma and to evaluate the relationship between coagulation, clinical, and laboratory variables, and disease and injury severity, as well as the ability of coagulation variables to predict the presence of body cavity hemorrhage (BCH), necessity of blood product administration, and outcome. DESIGN Prospective, multicenter, observational study. SETTING Two university teaching hospitals. ANIMALS Forty client-owned dogs sustaining severe blunt or penetrating trauma. INTERVENTIONS Blood samples were collected within 12 hours of the traumatic incident for measurement of blood gases, lactate concentration, platelet count, activated clotting time, prothrombin time, activated partial thromboplastin time (aPTT), fibrinogen concentration, antithrombin activity, D-dimer concentration, protein C activity, plasmin inhibition, plasminogen activity, and kaolin-activated thomboelastography. RESULTS Decreased platelet count was a risk factor for the presence of BCH (P = 0.006) and decreased platelet count (P < 0.001), protein C activity (P = 0.001), angle (α) (P = 0.001), maximum amplitude (MA) (P < 0.001), and clot strength (G) (P = 0.002) were risk factors for blood product administration. Nonsurviving dogs were hypocoagulable with prolonged aPTT (P = 0.008), decreased plasmin inhibition (P = 0.033), decreased α (P = 0.021), and decreased MA (P = 0.038) compared to surviving dogs. Multivariate analysis accounting for disease severity showed that prolonged aPTT (P = 0.004, OR = 1.74) was the strongest predictor of nonsurvival. Prolonged aPTT was positively correlated with APPLE-fast score (P < 0.001, r(2) = 0.35), lactate concentration (P < 0.001, r(2) = 0.35), and negative base excess (P = 0.001, r(2) = 0.27). Acute traumatic coagulopathy, as defined by 2 or more abnormal coagulation tests, was diagnosed in 15% of dogs at hospital admission and was more common in dogs with increased disease severity (P = 0.002), decreased systolic blood pressure (P = 0.002), and increased lactate concentration (P = 0.011). CONCLUSIONS In dogs with severe traumatic injuries and hypoperfusion, measurement of thromboelastography and aPTT should be considered to support clinical assessments in predicting the need for blood product administration and nonsurvival.

Ionized hypocalcemia as a prognostic indicator in dogs following trauma

OBJECTIVE To determine the incidence of ionized hypocalcemia (iHCa) in dogs with blunt and penetrating traumatic injuries upon presentation to a hospital, and to determine the association of iHCa with mortality, duration of hospitalization, and requirement for intensive care therapies. DESIGN Retrospective study (January 2007-December 2008). SETTING University veterinary teaching hospital. ANIMALS Eighty-eight dogs admitted to the ICU within 24 hours of a traumatic event and with assessment of a venous blood gas sample, including ionized calcium, at hospital admission. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Most dogs (72%) sustained injuries as a result of a motor vehicle accident. iHCa (<1.25 mmol/L [<2.50 mEq/L]) was present in 14 of 88 dogs (16%). Dogs with abdominal trauma were significantly more likely to have iHCa (P = 0.020) than dogs with other injuries. Dogs with iHCa spent significantly longer time in the hospital (P = 0.036) and ICU (P = 0.005), and were more likely to require oxygen supplementation (P = 0.048), synthetic colloids (P = 0.020), vasopressors (P = 0.0043), and blood transfusions (P < 0.0001). Six of 14 dogs (43%) with iHCa demonstrated clinical signs consistent with hypocalcemia during the course of hospitalization, and calcium gluconate was administered intravenously to one dog. Overall mortality was 16% (14/88) and dogs with iHCa were significantly less likely to survive (P < 0.001). CONCLUSIONS The incidence of iHCa upon hospital admission in this group of dogs with blunt and penetrating trauma is similar to the incidence of iHCa in critically ill dogs. Findings further suggest that dogs with iHCa are more severely injured and subsequently require increased intensive care therapies and have a lower likelihood of survival compared to dogs with normocalcemia. Ionized calcium concentration may therefore be a useful prognostic indicator in dogs with blunt and penetrating traumatic injuries.

Risk factors for transfusion-associated complications and nonsurvival in dogs receiving packed red blood cell transfusions: 211 cases (2008-2011)

OBJECTIVE To determine whether the number, volume, or age of transfused packed RBC units; volume of other blood products; or pretransfusion PCV was a risk factor for transfusion-associated complications or nonsurvival in dogs. DESIGN Retrospective case series. ANIMALS 211 client-owned dogs receiving stored packed RBC transfusions. PROCEDURES Information collected or calculated from the medical record of each dog included the total number, volume, and dose of packed RBC units; mean age of packed RBC units; number of packed RBC units > 14 days old; age of oldest packed RBC unit; volume and dose of other blood products used; pretransfusion PCV; acute patient physiologic and laboratory evaluation score; transfusion-associated complications; and outcome. RESULTS The dose (mL/kg) of other blood products transfused was a risk factor for transfusion-associated complications (OR, 1.03; 95% confidence interval [CI], 1.01 to 1.05). The pretransfusion PCV (OR, 1.13; 95% CI, 1.06 to 1.21) and dose of packed RBCs administered (OR, 1.04; 95% CI, 1.02 to 1.07) were risk factors for nonsurvival. Age of transfused packed RBC units was not identified as a risk factor for transfusion-associated complications or nonsurvival, but the study was statistically underpowered to detect this finding. CONCLUSIONS AND CLINICAL RELEVANCE Administration of larger doses of other non-packed RBC blood products was a risk factor for transfusion-associated complications, and a higher pretransfusion PCV and larger dose of packed RBCs administered were risk factors for nonsurvival. Prospective randomized studies are needed to determine whether conservative transfusion strategies will reduce transfusion-associated complications and improve outcome in dogs.

Investigation of the use of three electroencephalographic electrodes for long-term electroencephalographic recording in awake and sedated dogs

OBJECTIVE To compare electroencephalography (EEG) artifact associated with use of the subdermal wire electrode (SWE), gold cup electrode (GCE), and subdermal needle electrode (SNE) over an 8-hour period in sedated and awake dogs. ANIMALS 6 healthy dogs. PROCEDURES 8 EEG channels were recorded during 20-minute video-EEG recording sessions (intermittently at 0.5, 2, 4, 6, and 8 hours) with and without chlorpromazine sedation. Nonphysiologic artifacts were identified. Duration of artifact was summed for each channel. Number of unaffected channels (NUC) was determined. RESULTS NUC was significantly affected by electrode type and sedation over time; median for SWE (2.80 channels; 95% confidence interval [CI], 0.84 to 5.70 channels) was significantly different from medians for GCE (7.87 channels; 95% CI, 7.44 to 7.94 channels) and SNE (7.60 channels; 95% CI, 6.61 to 7.89 channels). After 4 hours, NUC decreased in awake dogs, regardless of electrode type. In awake dogs, duration of artifact differed significantly between SWE and GCE or SNE; medians at 8 hours were 61.55 seconds (95% CI, 21.81 to 173.65 seconds), 1.33 seconds (95% CI, 0.47 to 3.75 seconds), and 21.01 seconds (95% CI, 6.85 to 64.42 seconds), respectively. CONCLUSIONS AND CLINICAL RELEVANCE The SWE had a significant duration of artifact during recording periods > 2 hours, compared with results for the GCE and SNE, in awake dogs. The GCE, SNE, and sedation resulted in significantly more channels unaffected by artifact. For longer recordings, caution should be exercised in selecting EEG electrodes and sedation state, although differences among electrodes may not be clinically relevant.

Diagnostic Utility of Wireless Video-Electroencephalography in Unsedated Dogs

Background Poor agreement between observers on whether an unusual event is a seizure drives the need for a specific diagnostic tool provided by video‐electroencephalography (video‐EEG) in human pediatric epileptology. Objective That successful classification of events would be positively associated with increasing EEG recording length and higher event frequency reported before video‐EEG evaluation; that a novel wireless video‐EEG technique would clarify whether unusual behavioral events were seizures in unsedated dogs. Animals Eighty‐one client‐owned dogs of various breeds undergoing investigation of unusual behavioral events at 4 institutions. Methods Retrospective case series: evaluation of wireless video‐EEG recordings in unsedated dogs performed at 4 institutions. Results Electroencephalography achieved/excluded diagnosis of epilepsy in 58 dogs (72%); 25 dogs confirmed with epileptic seizures based on ictal/interictal epileptiform discharges, and 33 dogs with no EEG abnormalities associated with their target events. As reported frequency of the target events decreased (annually, monthly, weekly, daily, hourly, minutes, seconds), EEG was less likely to achieve diagnosis (P < 0.001). Every increase in event frequency increased the odds of achieving diagnosis by 2.315 (95% confidence interval: 1.36–4.34). EEG recording length (mean = 3.69 hours, range: 0.17–22.5) was not associated (P = 0.2) with the likelihood of achieving a diagnosis. Conclusions and Clinical Importance Wireless video‐EEG in unsedated dogs had a high success for diagnosis of unusual behavioral events. This technique offered a reliable clinical tool to investigate the epileptic origin of behavioral events in dogs.

Use of quantitative ultrasonography for noninvasive surveillance of the third metacarpal bone in racing and training Thoroughbreds

OBJECTIVE-To use quantitative ultrasonography to evaluate the association between the speed of sound (SOS) at 9 sites in the third metacarpal bone (MCIII) of racing Thoroughbreds with workload accumulation and the effect that MCIII failure has on this association. ANIMALS-Sixty-two 2- and 3-year-old Thoroughbreds in racing condition. PROCEDURES-Cumulative work index (CWI) was used to calculate total workload (CWI(total)) and also 3 independent CWIs for the various gaits (ie, trot [CWI(trot)], gallop [CWI(gallop)], and race [CWI(race)]) used during training and racing. Speed of sound was monitored in horses during the 2007 racing season and compared with the CWIs via regression analysis. Sex, age, limb, and MCIII failure were included as covariates in the model. RESULTS-SOS was significantly associated with CWI(total) at 8 sites and with independent CWIs of the various gaits at all 9 sites. Progression of SOS in MCIIIs with workload differed significantly in horses with clinical signs of metacarpal bone failure, compared with results for horses with clinically normal MCIIIs, in 1 site by use of CWI(total) and in 5 sites by use of the independent CWIs for the various gaits. CONCLUSIONS AND CLINICAL RELEVANCE-These results indicated that SOS in the MCIII of racing Thoroughbreds followed a constant pattern of progression as workload accumulated. With the development of more precise quantitative ultrasonography devices, SOS corrected for amount of activity may be used to identify horses at risk of bone failure.

The effect of topical lidocaine on muscle artefacts in awake canine electroencephalogram recordings

Muscle artefacts in electroencephalogram recording data interfere with diagnostic accuracy. Lidocaine may reduce these artefacts. The objective of this study was to determine the effect of topical lidocaine on muscle artefacts in unanesthetized canine electroencephalogram (EEG) recording data. Topical 4% lidocaine was applied to each electrode site for six treated dogs prior to subdermal wire electrode placement and compared against historical untreated controls. Twenty-minute recordings began 30 min after lidocaine application. Three epochs (early, middle, and end) were sampled from each recording and scored for muscle artefact incidence and severity by two blinded reviewers. No significant treatment effects on incidence and severity were found. Application of topical lidocaine does not appear to reduce the occurrence of muscle artefacts in canine EEG recordings.

COMPARISON BETWEEN CRANIAL THORACIC INTERVERTEBRAL DISC HERNIATIONS IN GERMAN SHEPHERD DOGS AND OTHER LARGE BREED DOGS

Cranial thoracic intervertebral disc herniations have been reported to be rare in dogs due to the presence of the intercapital ligament, however some studies have proposed they may not be uncommon in German Shepherd dogs. The purpose of this retrospective study was to compare cranial thoracic intervertebral disc herniations in German Shepherd dogs and other large breed dogs (control group). Medical records at the Ontario Veterinary College were searched for German Shepherd dogs and other large breed dogs that had magnetic resonance imaging studies including the T1-T9 region. For each dog and each disc space from T1-T9, three variables (compression, disc degeneration, and herniation) were recorded and graded based on review of sagittal T2-weighted images. Twenty-three German Shepherd dogs and 47 other large breed dogs met inclusion criteria. The German Shepherd dog group had higher scores than the control group for compression (P = 0.0099) and herniation (P < 0.001), but not disc degeneration (P = 0.97). In the German Shepherd dog group, intervertebral discs T2-T3 and T4-T5 had an increased risk for compression and T3-T4 had an increased risk for compression and herniation. Findings from this study indicated that German Shepherd dogs may be more likely than other large breed dogs to have spinal cord compression due to cranial thoracic disc herniations. Imaging of the cranial thoracic spine, including T2-T3, is recommended for German Shepherd dogs with T3-L3 neurological signs.