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OBJECTIVE: Rivaroxaban is a new anticoagulant option for dogs, yet its reported oral bioavailability is as low as 60%. The objective of this study was to examine the influence of feeding and gastroprotectant medications on the bioactivity (anti‐Xa activity) of rivaroxaban in healthy dogs. DESIGN: Prospective experimental study. SETTING: University research laboratory. ANIMALS: Five healthy neutered male purpose‐bred Beagles. INTERVENTIONS: Dogs were administered a median dose of 1.8 mg/kg rivaroxaban (range, 1.6‐1.8 mg/kg) orally once daily for 2 consecutive days with either (1) no food, (2) food, (3) sucralfate 30 minutes before rivaroxaban, or (4) omeprazole at the same time as rivaroxaban. Blood was collected from preplaced jugular catheters immediately before and at 6 time points after rivaroxaban administration (2, 4, 8, 24, 36, and 48 hours). A rivaroxaban calibrated anti‐Xa activity assay (RIVA) was used to monitor anticoagulant effect. MEASUREMENTS AND MAIN RESULTS: Rivaroxaban administration resulted in significant increases in RIVA (P = 0.02), with peak activities occurring 2 to 4 hours after dosingduring each study arm. No feeding was associated with significantly higher RIVA at the 36‐hour time point compared to all other treatment arms (P

OBJECTIVE To document if a transient hypercoagulable state occurs in healthy dogs following abrupt cessation of unfractionated heparin (UFH) therapy. DESIGN Prospective experimental pilot study. SETTING University research facility. ANIMALS Seven adult random-source male dogs. INTERVENTION Thromboelastography (TEG) and thrombin-antithrombin (TAT) complex formation were used to assess coagulation status in healthy dogs. Seven adult research dogs received 200-300 IU/kg subcutaneous UFH every 8 hours for 4 days. A final IV bolus of 100 IU/kg was given on day 4 and the peak measured heparin concentration 1 hour later is defined as the start of heparin withdrawal (time 0). Citrated whole blood samples were collected at baseline (prior to heparin administration) and 3, 6, 12, 30, and 48 hours after UFH withdrawal. At all time points, a kaolin-activated TEG was performed and citrated plasma for measurement of TAT concentration was collected for batch analysis. Fibrinogen concentration, PCV, total plasma proteins, and platelet count were measured at baseline and 48 hours after heparin withdrawal. MEASUREMENTS AND MAIN RESULTS Compared to baseline, TAT was increased 12 hours after heparin withdrawal and returned to baseline by 30 hours. TEG clot formation time (K) was decreased 30 and 48 hours after heparin withdrawal. CONCLUSION TAT results suggest that a transient increase in thrombin generation developed 12 hours after withdrawal of UFH therapy. Though clot kinetics were rapid compared to baseline beginning 30 hours after heparin withdrawal, a return to baseline was not documented. Future studies are warranted to determine the clinical relevance of these results and to evaluate the effect of UFH withdrawal in critically ill animals.

OBJECTIVE To evaluate a panel of coagulation assays for their potential utility in rivaroxaban monitoring as alternatives to the rivaroxaban-specific anti-Xa activity (RIVA). DESIGN Prospective experimental study. SETTING University research laboratory. ANIMALS Five healthy neutered male Beagles. INTERVENTIONS Dogs were administered a median dose of 1.8 mg/kg rivaroxaban (range, 1.6-1.8 mg/kg) orally once daily for 2 consecutive days as part of a pharmacodynamic study. Blood was collected from a preplaced jugular catheter at time points relative to their rivaroxaban administration (0, 2, 4, 8, 24, 36, and 48 h) for measurement of RIVA, prothrombin time (PT), activated partial thromboplastin time, RapidTEG, and thrombin generation variables. MEASUREMENTS AND MAIN RESULTS One hundred forty data points were available for analysis. There was poor correlation between RIVA and RapidTEG variables: R time (R) (min) (r = 0.554, P < 0.0001), K time (K) (min) (r = -0.204, P = 0.016), alpha angle (degrees) (r = 0.152, P = 0.073), Maximum amplitude (MA) (mm) (r = 0.106, P = 0.215), and G value (G) (dynes/s) (r = 0.108, P = 0.205). A good correlation was noted between thrombin generation variables and RIVA: lag time (min) (r = 0.827, P < 0.0001), peak (nM) (r = -0.752, P < 0.0001), and endogenous thrombin potential (nM·min) (r = -0.762, P < 0.0001). There was an excellent correlation between PT and RIVA (r = 0.915, P < 0.0001) and a good correlation between activated partial thromboplastin time and RIVA (r = 0.772, P < 0 .0001). CONCLUSIONS Of all the coagulation tests investigated, the PT correlated best with RIVA. There is potential for PT being a convenient second-line monitoring option in dogs receiving rivaroxaban, but further work is necessary to validate other PT assays. Thromboelastography performed with strong activators correlated poorly with anti-Xa activity.

Objective To compare the Lactate Plus handheld monitor to a reference blood gas analyzer for determining plasma lactate concentrations in canine whole blood. Design Prospective observational study. Setting University teaching hospital. Animals Ninety-four dogs hospitalized or admitted through the emergency service provided 125 blood samples. Only dogs that required a venous or arterial blood gas evaluation as a part of their diagnostic assessment or ongoing management were included. Interventions None. Measurements and Main Results Canine whole blood samples were assayed for plasma lactate concentration with a reference blood gas analyzer and the Lactate Plus monitor. Correlation and Bland–Altman analyses were used to compare results between the 2 methods. A subset of blood samples was repeatedly analyzed with the Lactate Plus to assess monitor precision. Plasma lactate measurements from the Lactate Plus monitor showed excellent correlation with those from the reference analyzer (ρ = 0.98, P 5 mmol/L. The coefficient of variation ranged from 0–26.2% (median, 3.7%) and was

Objective To characterize the correlation between thromboelastography (TEG) variables using strong activators and anti-Xa (AXa) activity in healthy dogs administered subcutaneous unfractionated heparin (UFH). Design Prospective experimental study. Setting University research facility. Animals Eight adult random-source male dogs. Intervention Dogs were randomized to receive subcutaneous UFH at 200, 250, or 300 IU/kg every 8 hours for a total of 10 injections. Blood samples were collected at time 0 (preheparin) and 3, 6, and 8 hours after the 1st (Day 1) and 10th (Day 4) UFH injection. After the 8-hour blood sample was obtained on day 4, a 100 IU/kg IV bolus of UFH was administered and an additional blood sample was collected 1 hour later (hour 9). AXa activity, activated partial thromboplastin time (aPTT), and TEG (with up to 5 activators) were performed at each time point. Modes of activation for TEG included recalcified (Ca), Ca with heparinase (CaH), CaH and tissue factor 1:3600 (CTF3600H), Ca with tissue factor 1:100 (CTF100), and RapidTEG. Spearman rank correlations were calculated for each of the aforementioned parameters and the AXa activity. P-values were corrected for multiple comparisons with a Bonferroni correction. Measurements and Main Results Significant correlations were found between AXa activity and the TEG R values generated with CTF100 (R = 0.83, P ≤ 0.0001) and RapidTEG (R = 0.90, P < 0.0001), as well as both forms of aPTT measurement (R = 0.86 and 0.84, P < 0.0001). Conclusions This study demonstrates that TEG variables derived using robust activation correlate with AXa activity as well as aPTT and have the potential to be used for monitoring UFH therapy in healthy dogs. Future studies are warranted to evaluate its diagnostic utility in critically ill animals.

Objective To examine available evidence on prehospital care in human and veterinary trauma and emergency medicine and develop best practice guidelines for use by both paramedical and nonparamedical personnel in the approach to the prehospital care of dogs and cats. Design Systematic evaluation of the literature gathered via medical databases searches of Medline, CAB abstracts, and Google Scholar. Synthesis From a review and systematic evaluation of the available evidence, consensus guidelines on the approach to prehospital care of dogs and cats in 18 scenarios were developed. Conclusions Due to the lack of current evidence in the veterinary prehospital arena, best practice guidelines were developed as an initial platform. Recommendations were based on a review of pertinent human and available veterinary literature as well as a consensus of the authors’ professional opinions. It is anticipated that evidence-based additions will be made in the future.

OBJECTIVE: Determine the correlation between kaolin‐activated thromboelastography (TEG) variables (R, K, angle, and maximum amplitude [MA]) and PCV, fibrinogen concentration (FC), and total fibrinogen (TF) in an ex vivo model. ANIMALS: Two healthy adult mixed‐breed dogs. PROCEDURES: Citrated whole blood was obtained and separated into packed red cells, platelet rich plasma, and platelet poor plasma (PPP). An aliquot of PPP was heated to denature heat labile proteins (fibrinogen, factor V, factor VIII). Blood components were recombined for analyses of 6 physiological scenarios: anemia with low fibrinogen; anemia with moderate fibrinogen; anemia with normal fibrinogen; anemia with normal saline; normal PCV and normal fibrinogen; and normal PCV and low fibrinogen. A Kruskal–Wallis test, along with linear regressions on pairwise combinations of TEG variables, was used to determine the correlation between TEG variables and PCV, FC, and TF. RESULTS: Maximum amplitude correlated with FC (R² 0.60, P < 0.001) and TF (R² 0.57, P < 0.001) but not PCV (R² 0.003, P = 0.7). Angle and K time were moderately correlated with FC ([angle: R² 0.53, P < 0.001]; [K: R² 0.55, P < 0.001]) and TF ([alpha angle: R² 0.52, P < 0.001]; [K: R² 0.51, P < 0.001]) but not PCV. The R time was weakly correlated with PCV (R² 0.15, P < 0.009) but not FC or TF. CONCLUSIONS AND CLINICAL RELEVANCE: In an ex vivo model, plasma proteins but not PCV impacted TEG variables. This suggests that TEG changes noted with anemia are imparted by changes in available fibrinogen in a fixed microenvironment rather than artifact of anemia.

Thromboelastography (TEG) provides a global evaluation of haemostasis. This diagnostic test is widely used in mammals but has not previously been performed in reptiles, mainly due to the limited availability of taxon-specific reagents. The objective of this pilot study was to establish a protocol to perform TEG in sea turtles. Pooled citrated plasma, stored at −80°C, from four green turtles (Chelonia mydas) was assayed on a TEG 5000. Several initiators were evaluated: kaolin (n=2), RapidTEG (n=2), fresh (n=2) and frozen (n=6) thromboplastin extracted from pooled brain tissue from several chelonian species, human recombinant tissue factor at 1:100 (n=1), Reptilase (n=2), and rabbit thromboplastin (n=1). Both fresh and frozen chelonian thromboplastin were superior in producing quantifiable TEG reaction time compared with all other reagents. These findings are consistent with the lack of an intrinsic pathway in turtles and confirmed a lack of coagulation in the turtle samples in response to mammalian thromboplastin. A TEG protocol was subsequently established for harvested species-specific frozen thromboplastin. The frozen thromboplastin reagent remained stable after one year of storage at −80°C. The developed protocol will be useful as a basis for future studies that aim to understand the pathophysiology of haemostatic disorders in various stranding conditions of sea turtles.

Objective To describe the clinical features, diagnostic findings, treatment, and outcome of a dog with acute abdominal pain and hemoperitoneum secondary to a presumptive intraperitoneal (IP) snakebite. Case Summary A 10-month-old castrated male mixed-breed dog was evaluated for suspected snake envenomation. The dog presented recumbent and tachycardic with signs of severe abdominal pain. Two cutaneous puncture wounds and hemoperitoneum were discovered during evaluation. Ultrasonographic examination revealed communication of the wounds with the peritoneal cavity. The dog was treated with supportive care, parenteral analgesia, packed red blood cell and fresh frozen plasma transfusions, crotalid antivenom, and placement of an IP catheter to provide local analgesia. The dog recovered fully and was discharged 5 days after initial presentation. New or Unique Information Provided To our knowledge, this is the first report of IP envenomation accompanied by hemorrhage treated with continuous IP analgesia in the veterinary literature.

Objective To characterize hemostasis and determine if disseminated intravascular coagulation (DIC) is present in cats with cytauxzoonosis. Design Cross-sectional study. Setting University teaching hospital. Animals Five client-owned cats with cytologic and PCR-confirmed cytauxzoonosis. Interventions None. Measurements and Main Results Admission samples were collected for hemostasis testing including platelet count, activated partial thromboplastin time, prothrombin time, fibrinogen, antithrombin (AT), d-dimer, protein C, plasminogen, antiplasmin, factors VII, VIII, IX, X, and XI, von Willebrand factor, and thromboelastography. Results were compiled for combined criteria used to define DIC, and all 5 cats satisfied criteria using a previously described modified scoring system for DIC in cats. The abnormalities found in all 5 cats included thrombocytopenia, low protein C activity, and prolonged prothrombin time; however, none of the cats had low AT activity. None of the cats had clinical signs of hemorrhage despite thrombocytopenia, coagulation factor deficiency (5/5 cats), and thromboelastographic evidence of hypocoagulability (2/5 cats). Three of 5 cats survived to hospital discharge. The nonsurvivors had disseminated cytauxzoonosis with schizont-laden macrophages in vessels of various organs. Conclusions This is the first report that comprehensively describes the hemostastic status of cats with naturally occurring infection with Cytauxzoon felis. All 5 cats had laboratory evidence of overt DIC. Unlike human and canine models of sepsis-induced DIC, AT deficiency was not found in this series of cats. Further research is warranted to investigate therapeutic strategies targeting thrombotic DIC to improve survival in cats with cytauxzoonosis.

Objective—To determine whether thromboelastography is more accurate than conventional methods of evaluating hemostasis for the prediction of clinical bleeding in thrombocytopenic dogs following total body irradiation (TBI) and bone marrow transplantation (BMT). Animals—10 client-owned thrombocytopenic dogs with multicentric lymphoma. Procedures—Results of a kaolin-activated thromboelastography assay, platelet count, and buccal mucosal bleeding time were evaluated for correlation to clinical bleeding. Results—Maximum amplitude, derived via thromboelastography, was the only hemostatic variable with significant correlation to clinical bleeding. Buccal mucosal bleeding time had a high sensitivity but poor specificity for identifying dogs with clinical bleeding. Conclusions and Clinical Relevance—Compared with buccal mucosal bleeding time and platelet count, thromboelastography was more reliable at identifying thrombocytopenic dogs with a low risk of bleeding and could be considered to help guide the use of transfusion products in dogs undergoing TBI and BMT.

Cold-stunning in sea turtles is a frequent natural cause of mortality and is defined as a hypothermic state due to exposure to water temperatures

Objective To systematically examine evidence surrounding definitions and reporting of data for viscoelastic testing in veterinary medicine. Design Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality, and development of consensus on conclusions for application of the concepts to clinical practice. Setting Academic and referral veterinary medical centers. Results Databases searched included Medline, CAB abstracts, and Google Scholar. Conclusions All 4 standard thromboelastography (TEG) and rotational thromboelastometry (ROTEM) variables should be universally reported, and the reporting of shear elastic modulus in addition to maximum amplitude (MA) is encouraged. There is insufficient evidence to support universal usage of the coagulation index at this time. The K value and clot formation time are the most variable of the 4 parameters, with alpha angle, MA, and maximum clot firmness generally the least variable. Individual studies should report sufficient data on patients and institutional controls to enable definitions of hypo- and hypercoagulability to be evaluated post-hoc, and it is recommended that all studies specifically report how these conditions were defined. In reporting data relating to fibrinolysis, the TEG variables LY30, LY60, CL30, CL60, and the ROTEM variables LI30, LI60, ML, LOT, and LT should be documented. Studies should report sufficient data on patients and controls to enable definitions of hyper- and hypofibrinolysis to be evaluated post-hoc, and we suggest that standard TEG/ROTEM assays may be unable to detect hypofibrinolysis in companion animals. We recommend that every center establish reference intervals, which are specific to either TEG or ROTEM. These reference intervals should be established using veterinary clinical pathology guidelines, standardized protocols, and a minimum of 40 healthy animals. There are currently insufficient data in companion animals to suggest a utility for Vcurve variables beyond that of standard TEG variables.

Objective To systematically examine the evidence relating to the performance of rotational viscoelastic testing in companion animals, to develop assay guidelines, and to identify knowledge gaps. Design Multiple questions were considered within 5 parent domains, specifically system comparability, sample handling, assay activation and test protocol, definitions and data reporting, and nonstandard assays. Standardized, systematic evaluation of the literature was performed. Relevant articles were categorized according to level of evidence and assessed for quality. Consensus was developed regarding conclusions for application of concepts to clinical practice. Setting Academic and referral veterinary medical centers. Results Databases searched included Medline, Commonwealth Agricultural Bureaux abstracts, and Google Scholar. Worksheets were prepared evaluating 28 questions across the 5 domains and generating 84 assay guidelines. Conclusions Evidence-based guidelines for the performance of thromboelastography in companion animals were generated through this process. Some of these guidelines are well supported while others will benefit from additional evidence. Many knowledge gaps were identified and future work should be directed to address these gaps and to objectively evaluate the impact of these guidelines on assay comparability within and between centers.

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, r2 = 0.35), lactate concentration (P < 0.001, r2 = 0.35), and negative base excess (P = 0.001, r2 = 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.

Background Stethoscopes are a potential source of nosocomial infection for hospitalized humans, a phenomenon not previously studied in companion animals. Objectives To determine if daily cleaning of stethoscope chest pieces reduces bacterial contamination between cleanings. Animals Client-owned dogs and cats. Methods Prospective observational study. In phase 1, bacterial cultures were obtained from the chest pieces of 10 participant stethoscopes once weekly for 3 weeks. In phase 2, stethoscopes were cleaned daily and 2 culture samples were obtained once weekly, immediately before and after cleaning with 70% isopropyl alcohol, for 3 weeks. Results Daily cleaning eliminated bacteria immediately after each cleaning (P = .004), but did not reduce the rate of positive cultures obtained before cleaning in phase 2. Cultures were positive for 20/30 (67%) samples during phase 1 and 18/30 (60%) obtained before daily cleaning during phase 2. Recovered organisms included normal skin flora, agents of opportunistic infections, and potential pathogens. The only genus that was repeatedly recovered from the same stethoscope for 2 or more consecutive weeks was Bacillus sp. Conclusions and Clinical Importance Daily cleaning was highly effective at removing bacteria, but provided no reduction in precleaning contamination. Cleaning stethoscopes after use on dogs or cats infected with pathogenic bacteria and before use on immunocompromised animals should be considered.

To document if a transient hypercoagulable state occurs in healthy dogs following abrupt cessation of unfractionated heparin (UFH) therapy.Prospective experimental pilot study.University research facility.Seven adult random-source male dogs.Thromboelastography (TEG) and thrombin-antithrombin (TAT) complex formation were used to assess coagulation status in healthy dogs. Seven adult research dogs received 200-300 IU/kg subcutaneous UFH every 8 hours for 4 days. A final IV bolus of 100 IU/kg was given on day 4 and the peak measured heparin concentration 1 hour later is defined as the start of heparin withdrawal (time 0). Citrated whole blood samples were collected at baseline (prior to heparin administration) and 3, 6, 12, 30, and 48 hours after UFH withdrawal. At all time points, a kaolin-activated TEG was performed and citrated plasma for measurement of TAT concentration was collected for batch analysis. Fibrinogen concentration, PCV, total plasma proteins, and platelet count were measured at baseline and 48 hours after heparin withdrawal.Compared to baseline, TAT was increased 12 hours after heparin withdrawal and returned to baseline by 30 hours. TEG clot formation time (K) was decreased 30 and 48 hours after heparin withdrawal.TAT results suggest that a transient increase in thrombin generation developed 12 hours after withdrawal of UFH therapy. Though clot kinetics were rapid compared to baseline beginning 30 hours after heparin withdrawal, a return to baseline was not documented. Future studies are warranted to determine the clinical relevance of these results and to evaluate the effect of UFH withdrawal in critically ill animals.

Objective – To determine whether the dose of antivenin administered is associated with a difference in survival of crotalid-envenomated dogs. A secondary objective was to determine whether other covariables affect survival. Design – Retrospective study (1988–2006). Setting – Private referral center and university small animal teaching hospital. Animals – Two hundred and eighteen dogs with evidence of crotalid envenomation and treatment with equine-derived antivenin. Interventions – Administration of antivenin. Measurements and Main Results – Patient signalment, physical and clinicopathologic data at time of presentation, treatments, complications of antivenin therapy, length and cost of hospitalization, and outcome were recorded. Confidence intervals were determined for the difference in median number of vials administered and for median dosage for patients that lived versus died. Penalized logistic regression was performed to evaluate the effect of other covariables on survival. The median age of affected dogs was 3 years (range 6 w–12 y) with a median weight of 25.7 kg (range 1.95–86.4 kg). The median number of antivenin vials administered was 1.0 (range 1.0–10.0). Acute and chronic reactions were reported in 7% (16/218) and 0.9% (2/218) of dogs, respectively. Nine of 218 dogs (4.1%) died. The median number of vials administered to the nonsurvivors and survivors were 2.0 (range 1–5 vials) and 1.0 (range 1–10 vials), respectively. The median number of vials received was significantly different in dogs that died versus those that lived (P

To examine available evidence on prehospital care in human and veterinary trauma and emergency medicine and develop best practice guidelines for use by both paramedical and nonparamedical personnel in the approach to the prehospital care of dogs and cats.Systematic evaluation of the literature gathered via medical databases searches of Medline, CAB abstracts, and Google Scholar.From a review and systematic evaluation of the available evidence, consensus guidelines on the approach to prehospital care of dogs and cats in 18 scenarios were developed.Due to the lack of current evidence in the veterinary prehospital arena, best practice guidelines were developed as an initial platform. Recommendations were based on a review of pertinent human and available veterinary literature as well as a consensus of the authors' professional opinions. It is anticipated that evidence-based additions will be made in the future.

To characterize the correlation between thromboelastography (TEG) variables using strong activators and anti-Xa (AXa) activity in healthy dogs administered subcutaneous unfractionated heparin (UFH).Prospective experimental study.University research facility.Eight adult random-source male dogs.Dogs were randomized to receive subcutaneous UFH at 200, 250, or 300 IU/kg every 8 hours for a total of 10 injections. Blood samples were collected at time 0 (preheparin) and 3, 6, and 8 hours after the 1st (Day 1) and 10th (Day 4) UFH injection. After the 8-hour blood sample was obtained on day 4, a 100 IU/kg IV bolus of UFH was administered and an additional blood sample was collected 1 hour later (hour 9). AXa activity, activated partial thromboplastin time (aPTT), and TEG (with up to 5 activators) were performed at each time point. Modes of activation for TEG included recalcified (Ca), Ca with heparinase (CaH), CaH and tissue factor 1:3600 (CTF3600H), Ca with tissue factor 1:100 (CTF100), and RapidTEG. Spearman rank correlations were calculated for each of the aforementioned parameters and the AXa activity. P-values were corrected for multiple comparisons with a Bonferroni correction.Significant correlations were found between AXa activity and the TEG R values generated with CTF100 (R = 0.83, P ≤ 0.0001) and RapidTEG (R = 0.90, P0.0001), as well as both forms of aPTT measurement (R = 0.86 and 0.84, P0.0001).This study demonstrates that TEG variables derived using robust activation correlate with AXa activity as well as aPTT and have the potential to be used for monitoring UFH therapy in healthy dogs. Future studies are warranted to evaluate its diagnostic utility in critically ill animals.

Objective: To describe a case of fatal anaphylaxis in a dog associated with a ‘routine’ dexamethasone suppression test. Case summary: An 8-year-old, spayed female dog, was treated with parenteral dexamethasone for a diagnosis of immune-mediated thrombocytopenia. The dog had responded to treatment, but 9 months later was evaluated for endogenous hyperadrenocorticism, prior to surgery for a ruptured anterior cruciate ligament. A normal ACTH stimulation test was followed by a high-dose dexamethasone suppression test. Immediately following the intravenous injection of dexamethasone, the dog developed severe anaphylactic shock and died. The postmortem examination findings supported the diagnosis of anaphylaxis. New information provided: The anaphylaxis in this dog was fulminating and by-passed the usual early signs of drug hypersensitivity. This is the first case in the veterinary literature reporting on dexamethasone as the cause of this dog's catastrophic event.

Objective—To evaluate equine IgG as a treatment for kittens with failure of passive transfer of immunity (FPT).Animals—13 specific pathogen-free queens and their 77 kittens.Procedure—Kittens were randomized at birth into 9 treatment groups. One group contained colostrumfed (nursing) kittens; the other groups contained colostrum-deprived kittens that were administered supplemental feline or equine IgG PO or SC during the first 12 hours after birth. Blood samples were collected at serial time points from birth to 56 days of age for determination of serum IgG concentrations. The capacity of equine IgG to opsonize bacteria for phagocytosis by feline neutrophils was determined via flow cytometry.Results—Kittens that received feline or equine IgG SC had significantly higher serum IgG concentrations than those of kittens that received the supplements PO. In kittens that were administered supplemental IgG SC, serum IgG concentrations were considered adequate for protection against infection. The half-life of IgG in kittens treated with equine IgG was shorter than that in kittens treated with feline IgG. Feline IgG significantly enhanced the phagocytosis of bacteria by feline neutrophils, but equine IgG did not.Conclusions and Clinical Relevance—Serum concentrations of equine IgG that are considered protective against infection are easily attained in kittens, but the failure of these antibodies to promote bacterial phagocytosis in vitro suggests that equine IgG may be an inappropriate treatment for FPT in kittens. (Am J Vet Res2003;64:969–975)

Two dogs with simultaneous congenital and acquired portosystemic shunts are reported. The first dog was an eight–month-old, male Golden Retriever with a history of peritoneal effusion, polyuria/ polydipsia, and stunted growth. The dog had a microcytic, hypochromic anemia, a mildly elevated AST, and a moderate to severely elevated preprandial and postprandial serum bile acids. Transcolonic portal scintigraphy confirmed the presence of a portosystemic shunt. An intraoperative mesenteric portogram was performed. Two conjoined congenital extrahepatic portosystemic shunts and multiple acquired extrahepatic portosystemic shunts were identified. The second dog was a five-month-old, mixed breed with two week history of peritoneal effusion. Abdominal ultrasound and transcolonic scintigraphy were used to diagnose a portosystemic shunt. A single extrahepatic portosystemic shunt, portal hypertension, and multiple acquired collateral shunts were identified at surgery. The histologic alterations observed in these dogs were consistent with a portosystemic shunt. In these dogs, the presence of congenital and acquired portosystemic shunts and histopathologic findings are considered to represent a combination of congenital portosystemic shunts and noncirrhotic portal hypertension or portal vein hypoplasia.

To compare the Lactate Plus handheld monitor to a reference blood gas analyzer for determining plasma lactate concentrations in canine whole blood.Prospective observational study.University teaching hospital.Ninety-four dogs hospitalized or admitted through the emergency service provided 125 blood samples. Only dogs that required a venous or arterial blood gas evaluation as a part of their diagnostic assessment or ongoing management were included.None.Canine whole blood samples were assayed for plasma lactate concentration with a reference blood gas analyzer and the Lactate Plus monitor. Correlation and Bland-Altman analyses were used to compare results between the 2 methods. A subset of blood samples was repeatedly analyzed with the Lactate Plus to assess monitor precision. Plasma lactate measurements from the Lactate Plus monitor showed excellent correlation with those from the reference analyzer (ρ = 0.98, P0.0001). Bland-Altman analysis revealed a small bias (0.1296). Agreement between the 2 methods was less consistent for lactate concentrations5 mmol/L. The coefficient of variation ranged from 0-26.2% (median, 3.7%) and was15% for 50/53 samples.The Lactate Plus provides a fast and affordable method to measure plasma lactate concentration in dogs. Results showed excellent agreement with the reference analyzer and precision of the instrument was acceptable.

Copperhead envenomation is common within the US, and no studies exist describing the clinical course of copperhead envenomation in dogs. Almost all treatment decisions regarding those bites are extrapolated from retrospective studies evaluating the clinical course of rattlesnake bites. Because copperheads and rattlesnakes produce venom with different potency, assumptions that treatment of the different envenomations should be similar may be incorrect. The purpose of this retrospective study was to evaluate the clinical course of copperhead envenomation in dogs and administered treatments. Medical records of 52 dogs treated for copperhead envenomation were reviewed, and owners were contacted regarding outcome. The most common clinical signs associated with copperhead envenomation included swelling, pain, and ecchymosis. Clinicopathological abnormalities (e.g., thrombocytopenia, elevated clotting times, leukocytosis) were mild, and red blood cell morphology changes and coagulopathies were rare. Most dogs were treated with antimicrobials, analgesics, and fluid therapy. No dogs in this study required the use of antivenin and all survived to discharge. This study found that the clinical course after copperhead envenomation is generally limited to local rather than systemic illness. Copperhead envenomation in dogs is largely self-limiting and responsive to supportive care with hospitalization for monitoring.

A study was initiated to determine the prevalence of positive blood cultures, to identify the primary isolates and to assess possible sources of contamination in captive lizards. Fifty-eight blood cultures were made from 28 lizards from eight species belonging to the families Helodermatidae, Iguanidae, Scincidae and Varanidae. Bacterial growth was obtained from 51 of the 58 cultures (88%). More than one Clostridium species was present in 79% of all positive cultures. The four most common isolates in descending order of frequency were C. sordelli, C. innocuum, C. perfringens and C. difficile. A possible contamination source are spores imbedded deeply in the folds of the skin and scales at the venipuncture site. However, it is also possible that Clostridia are normally present in the blood of lizards without producing overt disease. The interpretation of positive cultures of blood samples taken from the tail of lizards should be made with caution as definitive evidence for disease.

To systematically examine evidence surrounding definitions and reporting of data for viscoelastic testing in veterinary medicine.Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence and quality, and development of consensus on conclusions for application of the concepts to clinical practice.Academic and referral veterinary medical centers.Databases searched included Medline, CAB abstracts, and Google Scholar.All 4 standard thromboelastography (TEG) and rotational thromboelastometry (ROTEM) variables should be universally reported, and the reporting of shear elastic modulus in addition to maximum amplitude (MA) is encouraged. There is insufficient evidence to support universal usage of the coagulation index at this time. The K value and clot formation time are the most variable of the 4 parameters, with alpha angle, MA, and maximum clot firmness generally the least variable. Individual studies should report sufficient data on patients and institutional controls to enable definitions of hypo- and hypercoagulability to be evaluated post-hoc, and it is recommended that all studies specifically report how these conditions were defined. In reporting data relating to fibrinolysis, the TEG variables LY30, LY60, CL30, CL60, and the ROTEM variables LI30, LI60, ML, LOT, and LT should be documented. Studies should report sufficient data on patients and controls to enable definitions of hyper- and hypofibrinolysis to be evaluated post-hoc, and we suggest that standard TEG/ROTEM assays may be unable to detect hypofibrinolysis in companion animals. We recommend that every center establish reference intervals, which are specific to either TEG or ROTEM. These reference intervals should be established using veterinary clinical pathology guidelines, standardized protocols, and a minimum of 40 healthy animals. There are currently insufficient data in companion animals to suggest a utility for Vcurve variables beyond that of standard TEG variables.

To characterize hemostasis and determine if disseminated intravascular coagulation (DIC) is present in cats with cytauxzoonosis.Cross-sectional study.University teaching hospital.Five client-owned cats with cytologic and PCR-confirmed cytauxzoonosis.None.Admission samples were collected for hemostasis testing including platelet count, activated partial thromboplastin time, prothrombin time, fibrinogen, antithrombin (AT), d-dimer, protein C, plasminogen, antiplasmin, factors VII, VIII, IX, X, and XI, von Willebrand factor, and thromboelastography. Results were compiled for combined criteria used to define DIC, and all 5 cats satisfied criteria using a previously described modified scoring system for DIC in cats. The abnormalities found in all 5 cats included thrombocytopenia, low protein C activity, and prolonged prothrombin time; however, none of the cats had low AT activity. None of the cats had clinical signs of hemorrhage despite thrombocytopenia, coagulation factor deficiency (5/5 cats), and thromboelastographic evidence of hypocoagulability (2/5 cats). Three of 5 cats survived to hospital discharge. The nonsurvivors had disseminated cytauxzoonosis with schizont-laden macrophages in vessels of various organs.This is the first report that comprehensively describes the hemostastic status of cats with naturally occurring infection with Cytauxzoon felis. All 5 cats had laboratory evidence of overt DIC. Unlike human and canine models of sepsis-induced DIC, AT deficiency was not found in this series of cats. Further research is warranted to investigate therapeutic strategies targeting thrombotic DIC to improve survival in cats with cytauxzoonosis.

To describe the clinical features, diagnostic findings, treatment, and outcome of a dog with acute abdominal pain and hemoperitoneum secondary to a presumptive intraperitoneal (IP) snakebite.A 10-month-old castrated male mixed-breed dog was evaluated for suspected snake envenomation. The dog presented recumbent and tachycardic with signs of severe abdominal pain. Two cutaneous puncture wounds and hemoperitoneum were discovered during evaluation. Ultrasonographic examination revealed communication of the wounds with the peritoneal cavity. The dog was treated with supportive care, parenteral analgesia, packed red blood cell and fresh frozen plasma transfusions, crotalid antivenom, and placement of an IP catheter to provide local analgesia. The dog recovered fully and was discharged 5 days after initial presentation.To our knowledge, this is the first report of IP envenomation accompanied by hemorrhage treated with continuous IP analgesia in the veterinary literature.

Objective—To evaluate effects of blood collection method and site on results of thromboelastography in healthy dogs. Animals—8 clinically normal purpose-bred dogs. Procedures—Blood was collected from the external jugular vein by syringe aspiration via direct venipuncture with a 20-gauge needle, through a central venous catheter, or into an evacuated tube with a 21-gauge winged needle catheter. Blood was collected from the lateral saphenous vein by syringe aspiration via direct venipuncture with a 20-gauge needle or into an evacuated tube with a 21-gauge winged needle catheter. Kaolin-activated thromboelastographic analyses were performed, and R (reaction time), K (clot formation time), α angle, maximal amplitude, and G (global clot strength) were analyzed. Results—No significant differences were observed with regard to sampling site. Sample collection method had no effect on thromboelastographic results for saphenous vein samples. Blood samples collected from the jugular vein by syringe aspiration had a lower R and K and higher α angle than did blood samples collected from the jugular vein by evacuated tube collection. Significant differences were observed between blood samples collected from the jugular vein by syringe aspiration and samples collected from the saphenous vein by evacuated tube collection and between samples collected from the saphenous vein by evacuated tube collection and samples collected from the jugular vein through a central venous catheter. Conclusions and Clinical Relevance—Different sampling methods resulted in small but significant differences in thromboelastographic values. Results justify the use of standardized techniques for research purposes, but all of these sampling methods were acceptable for 1-time clinical use.

Background Dogs with protein-losing nephropathy (PLN) are at risk of thromboembolic disease, but the mechanism leading to hypercoagulability and the population of dogs at risk are unknown. Objectives To characterize thromboelastography (TEG) and its association with serum albumin (SALB), UPC, and antithrombin activity in dogs with PLN. Animals Twenty-eight client-owned dogs with PLN (urine protein:creatinine ratio [UPC] > 2.0) and 8 control dogs were prospectively enrolled in this observational study. Methods TEG parameters, antithrombin activity, serum biochemical profiles, and UPC were measured. TEG analyses were run in duplicate with kaolin activation; reaction time (R), clot formation time (K), α-angle (α), maximal amplitude (MA), and global clot strength (G) were analyzed. Results Dogs with PLN had lower K (P = .004), and higher α (P = .001), MA (P

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.Prospective, multicenter, observational study.Two university teaching hospitals.Forty client-owned dogs sustaining severe blunt or penetrating trauma.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.Decreased platelet count was a risk factor for the presence of BCH (P = 0.006) and decreased platelet count (P0.001), protein C activity (P = 0.001), angle (α) (P = 0.001), maximum amplitude (MA) (P0.001), 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 (P0.001, r(2) = 0.35), lactate concentration (P0.001, 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).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.

Objective—To evaluate the effect of acepromazine maleate administered IV on platelet function assessed in healthy dogs by use of a modified thromboelastography assay. Animals—6 healthy adult mixed-breed dogs. Procedures—Dogs received each of 3 treatments (saline [0.9% NaCl] solution [1 to 2 mL, IV] and acepromazine maleate [0.05 and 0.1 mg/kg, IV]) in a randomized crossover study with a minimum 3-day washout period between treatments. From each dog, blood samples were collected via jugular venipuncture immediately before and 30 and 240 minutes after administration of each treatment. A modified thromboelastography assay, consisting of citrated kaolin–activated (baseline assessment), reptilase-ADP–activated (ADP-activated), and reptilase-arachidonic acid (AA)–activated (AA-activated) thromboelastography, was performed for each sample. Platelet inhibition was evaluated by assessing the percentage change in maximum amplitude for ADP-activated or AA-activated samples, compared with baseline values. Percentage change in maximum amplitude was analyzed by use of Skillings-Mack tests with significance accepted at a family-wise error rate of P < 0.05 by use of Bonferroni corrections for multiple comparisons. Results—No significant differences were found in the percentage change of maximum amplitude from baseline for ADP-activated or AA-activated samples among treatments at any time. Conclusions and Clinical Relevance—Platelet function in dogs, as assessed by use of a modified thromboelastography assay, was not inhibited by acepromazine at doses of 0.05 or 0.1 mg/kg, IV. This was in contrast to previous reports in which it was suggested that acepromazine may alter platelet function via inhibition of ADP and AA.

Objective—To investigate effects of IV administration of dextrose on coagulation in healthy dogs. Animals—7 dogs. Procedures—Thromboelastography and coagulation panel analysis were used to assess coagulation. Samples (S1 through S9) were collected during the study phases: phase 0 (S1 [baseline]); phase 1 (S2 and S3), infusion of crystalloid fluid without dextrose; phase 2 (S4 and S5), high-rate dextrose infusion; phase 3 (S6, S7, and S8), moderate-rate dextrose infusion; and phase 4 (S9), discontinuation of fluids for 24 hours. In phase 3, dogs were allocated to 2 groups; 1 was administered dextrose at a rate comparable to total parental nutrition (40% of resting energy requirement; group A), and 1 was administered dextrose at rates equaling 70% to 90% of resting energy requirement (group B). Blood glucose concentration was measured every 2 hours. Results—No dogs had clinically relevant sustained hyperglycemia. Maximum amplitude and elastic shear modulus were significantly lower at S6 than at S1 through S4. Concentration of D-dimer was significantly higher at S6 than at S1, S3, and S4 and significantly higher at S5 than at S3. Prothrombin time was significantly prolonged at S3, S5, S7, S8, and S9, compared with the value at S1. Activated partial thromboplastin time was significantly prolonged at S5 and S6, compared with values at S1, S2, S3, S4, and S9. Conclusions and Clinical Relevance—IV administration of dextrose to healthy dogs at rates comparable to or higher than those for conventional parenteral nutrition resulted in mild but clinically unimportant interference with coagulation.

To determine whether the dose of antivenin administered is associated with a difference in survival of crotalid-envenomated dogs. A secondary objective was to determine whether other covariables affect survival.Retrospective study (1988-2006).Private referral center and university small animal teaching hospital.Two hundred and eighteen dogs with evidence of crotalid envenomation and treatment with equine-derived antivenin.Administration of antivenin.Patient signalment, physical and clinicopathologic data at time of presentation, treatments, complications of antivenin therapy, length and cost of hospitalization, and outcome were recorded. Confidence intervals were determined for the difference in median number of vials administered and for median dosage for patients that lived versus died. Penalized logistic regression was performed to evaluate the effect of other covariables on survival. The median age of affected dogs was 3 years (range 6 w-12 y) with a median weight of 25.7 kg (range 1.95-86.4 kg). The median number of antivenin vials administered was 1.0 (range 1.0-10.0). Acute and chronic reactions were reported in 7% (16/218) and 0.9% (2/218) of dogs, respectively. Nine of 218 dogs (4.1%) died. The median number of vials administered to the nonsurvivors and survivors were 2.0 (range 1-5 vials) and 1.0 (range 1-10 vials), respectively. The median number of vials received was significantly different in dogs that died versus those that lived (P0.05). Increased heart rate (P=0.02) and petechiation (P=0.04) were associated with decreased likelihood of survival, while diphenhydramine (P=0.02) and fluoroquinolone (P=0.046) administration was associated with increased likelihood of survival. The median duration of hospitalization was 1.0 day (range 2 h-22 d). The median cost of hospitalization was US$1592.00 (range US$267.20-US$6738.00).The administration of more vials of antivenin is potentially associated with negative outcome; however, a causal relationship has not been established. Controlled, prospective studies are needed to optimize antivenin administration.

Case Description—A 7-year-old Spaniel-crossbreed dog was evaluated for stertorous breathing and inspiratory stridor. Clinical Findings—A temporary tracheotomy tube was placed prior to referral. Results of physical examination at our facility, including thoracic auscultation, were unremarkable. Examination of the larynx revealed a 2 × 2-cm nodular mass on the lateral aspect of the epiglottis and left arytenoid cartilage. Cytologic examination of the mass indicated septic suppurative inflammation and intracellular rod-shaped bacteria. During the procedures, decreased air movement through the temporary tracheotomy tube was detected, and the tube was replaced. A thrombus was found on the distal end of the temporary tracheotomy tube; the thrombus obstructed 90% of the tube lumen. Approximately 12 hours later, auscultation revealed decreased sounds in all lung fields. Cervical and thoracic radiography revealed an intraluminal soft tissue opacity distal to the tracheotomy tube. A thrombus that contained hair and plant material was removed from the trachea by use of an embolectomy catheter and videogastroscope. Approximately 30 hours after removal of the initial thrombus, the dog had an episode of respiratory distress. Cervical radiography revealed another intraluminal opacity. It was another thrombus, which also was removed by use of the videogastroscope. Treatment and Outcome—Tracheoscopy was performed with a videogastroscope in an attempt to remove the thrombi. A Fogarty catheter was used to remove the initial intraluminal thrombus from the trachea. Clinical Relevance—Airway obstruction resulting from an intraluminal thrombus in the trachea should be considered as a secondary complication after tracheotomy tube placement.

A 12-year-old, neutered male, domestic long-hair cat was evaluated for a 6-month history of inspiratory stertor and epiphora. In computed tomography of the skull and pelvis, and radiographs of the thorax, right femur and stifle there was generalized osteosclerosis, with obliteration of the nasal turbinates and nasolacrimal duct obstruction. The cat also had a large fibrosarcoma involving the right pelvic limb. Osteosclerosis is a rare disorder that is poorly understood but has been described in several species. Various manifestations, potential causes, and radiologic findings of osteosclerosis are discussed.

Objective—To determine whether passive transfer of IgG in neonatal kittens affects plasma opsonic capacity and neutrophil phagocytic and oxidative burst responses to bacteria in vitro.Animals—22 kittens from 6 specific pathogen-free queens.Procedure—Kittens were randomized at birth into the following treatment groups: colostrum-fed, colostrum-deprived, or colostrum-deprived supplemented with feline or equine IgG. Blood samples were collected at intervals from birth to 56 days of age. Plasma IgG concentrations were determined by radial immunodiffusion assay. Neutrophil function was assessed by a flow cytometry assay providing simultaneous measurement of bacteria-induced phagocytosis and oxidative burst. The opsonic capacity of kitten plasma was determined in an opsonophagocytosis assay with bacteria incubated in untreated or heat-inactivated plasma.Results—Among treatment groups, there were no significant differences in neutrophil phagocytic and oxidative burst responses to bacteria or opsonic capacity of plasma. In all samples of plasma, inactivation of complement and other heat-labile opsonins significantly reduced the opsonic capacity. Plasma IgG concentrations in kittens did not correlate with neutrophil function or plasma opsonic capacity before or after inactivation of complement.Conclusions and Clinical Relevance—The plasma opsonic capacity and neutrophil phagocytic and oxidative burst responses in vitro of kittens receiving passive transfer of IgG via colostrum intake or IgG supplementation and those deprived of colostrum were similar. The alternate complement pathway or other heat-labile opsonins may be more important than IgG in bacterial opsonization and phagocytosis. (Am J Vet Res2003;64:538–543)