Kaolin activation of recalcified citrated whole blood in a point-of-care viscoelastic coagulation test.

The viscoelastic coagulation monitor (VCM) is described as a point-of-care analyzer relying on activation of fresh whole blood (FWB) via contact between 2 glass plates. Kaolin is used as an activator in thromboelastography to reduce variability and shorten clotting times. The goal of this study was to compare VCM results from kaolin-activated, recalcified citrated samples with that from FWB. The VCM testing was performed using FWB and kaolin-activated, recalcified citrated samples. The VCM results were recorded for clot time (CT; seconds), clot formation time (CFT; seconds), alpha (degree), amplitude at 10 and 20 minutes (A10 and A20; VCM units), maximum clot firmness (MCF; VCM units), and lysis index (LI; %). Values were compared using a t-test or Wilcoxon-Mann-Whitney test, with a P-value < 0.05 considered significant. Variability between samples was calculated using Levene's test. The VCM kaolin activation resulted in significantly faster CT and CFT (P < 0.0001), higher alpha angle (P < 0.001), and higher A10 and A20 (P = 0.007, P = 0.015) compared to FWB. There was no difference in MCF, LI30, or LI45. There was no difference in variability identified. The addition of kaolin to recalcified citrated whole blood VCM samples results in more rapid clotting of FWB alone and could be considered for clinical use in dogs.

Le moniteur de coagulation viscoélastique (VCM) évalue l'hémostase au point de service en utilisant du sang entier frais activé au contact de deux disques de verre. Le kaolin est un activateur utilisé en thromboélastographie pour réduire la variabilité et raccourcir le temps de coagulation.Le but de cette étude était de comparer les résultats du VCM obtenus sur des échantillons citratés recalcifiés et activés par du kaolin, avec ceux obtenus sur sang entier frais. Les échantillons sanguins ont été prélevés sur des chiens sains. Les tests avec le VCM ont été réalisés sur des échantillons de sang entier frais et sur des échantillons de sang citraté recalcifié et activé par du kaolin. Les résultats du VCM ont été enregistrés : temps de coagulation (CT; secondes), temps de formation du caillot (CFT; secondes), angle alpha (degrés), amplitude à 10 et 20 minutes (A10 et A20; unités VCM), fermeté maximale du caillot (MCF; unités VCM), index de lyse à 30 et 45 minutes après la MCF (LI; pourcentage). Les valeurs ont été comparées à l'aide d'un un test t apparié ou un test de Wilcoxon-Mann-Whitney, avec une valeur P < 0,05 considérée comme significative. La variabilité entre les échantillons a été calculée à l'aide d'un test de Levene.Les résultats du VCM réalisé sur les échantillons activés par du kaolin présentaient une diminution significative du CT et CFT (P < 0,0001) ainsi qu'une augmentation significative de l'angle alpha (P < 0,001) et de A10 et A20 (P = 0,007, P = 0,015). Aucune différence n'a été démontrée dans la MCF, l'index LI30 ou LI45. Aucune différence de variabilité n'a été identifiée.L'ajout du kaolin aux échantillons VCM de sang entier citraté recalcifié aboutit à une activation de la coagulation plus rapide que par simple contact avec les disques de verre et pourrait être envisagé pour l'usage clinique chez le chien.(Traduit par les auteurs).

Viscoelastic Coagulation Testing in Exotic Animals.

Whole blood viscoelastic coagulation testing (VCT) allows global assessment of hemostasis and fibrinolysis. Although not widely used in exotic animal practice, VCT has been used in exotic animal research settings. Differences in patient demographics and analytical variables can result in dramatically different results with the same analyzer. To improve the utility of VCT in exotic animal medicine, standardization of protocols is necessary to facilitate the establishment of reference intervals. Despite these challenges, the quantitative/qualitative nature of VCT has already proved its real-world value to some clinicians.

2022 Update of the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) Domain 1- Defining populations at risk.

OBJECTIVES: To expand the number of conditions and interventions explored for their associations with thrombosis in the veterinary literature and to provide the basis for prescribing recommendations. DESIGN: A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. The revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated in this iteration included heartworm disease (dogs and cats), immune-mediated hemolytic anemia (cats), protein-losing nephropathy (cats), protein-losing enteropathy (dogs and cats), sepsis (cats), hyperadrenocorticism (cats), liver disease (dogs), congenital portosystemic shunts (dogs and cats) and the following interventions: IV catheters (dogs and cats), arterial catheters (dogs and cats), vascular access ports (dogs and cats), extracorporeal circuits (dogs and cats) and transvenous pacemakers (dogs and cats). RESULTS: Of the diseases evaluated in this iteration, a high risk for thrombosis was defined as heartworm disease or protein-losing enteropathy. Low risk for thrombosis was defined as dogs with liver disease, cats with immune-mediated hemolytic anemia, protein-losing nephropathy, sepsis, or hyperadrenocorticism. CONCLUSIONS: Associations with thrombosis are outlined for various conditions and interventions and provide the basis for management recommendations. Numerous knowledge gaps were identified that represent opportunities for future studies.

Evaluation of coagulation parameters in dogs with gallbladder mucoceles.

BACKGROUND: Gallbladder mucocele (GBM) is a common biliary disorder in dogs. Limited information is available on the coagulation status of dogs with GBM. HYPOTHESIS/OBJECTIVES: To determine patterns of coagulation alterations in dogs with GBM and correlate them with clinicopathologic abnormalities and ultrasonographic findings of disease severity. ANIMALS: Twenty-three dogs with GBM identified on ultrasound examination were prospectively enrolled. METHODS: At the time of GBM identification, blood and urine were collected for CBC, serum biochemical panel, urinalysis, prothrombin time, activated partial thromboplastin time (aPTT), factor VIII, protein C (PC), von Willebrand's factor (vWF), antithrombin activity, fibrinogen, D-dimers, and thromboelastrography (TEG). Gallbladder mucoceles were classified into ultrasound types 1 to 5. Medical records were reviewed for clinical presentation, underlying conditions and to determine if systemic inflammatory response syndrome (SIRS) was present. RESULTS: Based on TEG parameters, maximal amplitude, and G, 19/23 (83%) of dogs with GBM had evaluations consistent with hypercoagulability. On plasma-based coagulation testing, dogs with GBM had increased total PC activity (20/23, 87%), fibrinogen (9/23, 39%), platelet count (9/23, 39%), and D-dimers (6/15, 40%) as well as prolongations in aPTT (9/22, 41%) and low vWF activity (5/21, 24%). No correlation was found between TEG G value and any coagulation or clinical pathology variables, ultrasound stage of GBM or disease severity as assessed by the presence of SIRS. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with ultrasonographically identified GBM have changes in whole blood kaolin-activated TEG supporting a hypercoagulable state although traditional plasma-based coagulation testing suggests that a complex state of hemostasis exists.

Effect of time until sample analysis on lactate in dogs with shock.

INTRODUCTION: Lactate concentrations can increase with hypoperfusion in dogs and could be used as a prognostic indicator in sick dogs. In a busy emergency service, sample evaluation could be delayed. However, sample evaluation delays have been shown to cause lactate concentration increases in healthy dogs. In sick dogs, the magnitude of increased lactate is unknown. The goal of this study was to prospectively evaluate the effect of room temperature storage times on lactate measurements in dogs presenting to an emergency service. METHODS: We evaluated the precision and accuracy of the NOVA Lactate Plus, using standard procedures. To assess the impact of time on lactate concentrations in sick dogs, we prospectively enrolled dogs presenting to an emergency service. Lactate concentrations were measured at six time points using samples stored at room temperature. A Friedman test, followed by a Wilcoxon rank test with a Bonferroni correction was used to evaluate time points. RESULTS: Forty-five dogs were enrolled in this prospective observational study. The Lactate Plus and table-top analyzer compared favorably, with an R2 of .98, and a mean bias of 0.26 in 50 canine samples. Precision was acceptable, with a percent coefficient of variation of 5.39. Statistically significant increases in lactate concentrations were found at all time points over baseline (P = .008). CONCLUSIONS: In as little as 7.5 minutes, lactate concentrations increased significantly in samples stored at room temperature. Dogs with lower initial lactate concentrations had had higher increases in lactate concentration percentages over 90 minutes.

Clinical application of the American College of Veterinary Emergency and Critical Care (ACVECC) Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines to small animal cases.

OBJECTIVE: To illustrate the application of the Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines to the management of dogs and cats at risk of developing thrombosis using a case-based approach. ETIOLOGY: Dogs and cats become at risk of developing thrombosis from a wide range of conditions. These conditions often involve a specific insult followed by an inflammatory response and when combined with other contributing factors (eg, hypercoagulability, vascular endothelial injury, hemodynamic changes) create favorable conditions for thrombosis. DIAGNOSIS: Development of thrombosis in small animals remains challenging to demonstrate. Compatible clinical signs, the presence of known risk factors, and supporting diagnostic tests may be highly suggestive of the development of thrombosis. THERAPY: Therapeutic recommendations in accordance with the CURATIVE guidelines for dogs and cats are described in specific case vignettes presented. Discussion is centered on antithrombotic drug choices and dosing protocols, as outlined in Domains 2 and 3 of the CURATIVE guidelines. Where appropriate, guidelines related to therapeutic monitoring (Domain 4) and discontinuation of antithrombotics (Domain 5) were included. PROGNOSIS: In small animals at risk of developing thrombosis, overall prognosis may be improved by following consensus-based recommendations on the use of antithrombotics as outlined in the CURATIVE guidelines. Whether such interventions have any impact on outcome requires further investigation.

Effect of urinary bladder lavage on in-hospital recurrence of urethral obstruction and durations of urinary catheter retention and hospitalization for male cats.

OBJECTIVE To evaluate the effect of urinary bladder lavage on in-hospital recurrence of urethral obstruction (UO) and durations of urinary catheter retention and hospitalization for male cats. DESIGN Randomized controlled clinical trial. ANIMALS 137 male cats with UO. PROCEDURES Following random allocation, cats either did (flush group; n = 69) or did not (no-flush group; 68) undergo urinary bladder lavage with saline (0.9% NaCl) solution after alleviation of the obstruction and placement of a urethral catheter. Signalment, prior history of UO, presence of crystalluria, difficulty of urinary tract catheterization, in-hospital UO recurrence rate, and durations of urinary catheter retention and hospitalization were compared between the flush and no-flush groups. RESULTS Baseline characteristics did not differ significantly between the 2 treatment groups. The in-hospital UO recurrence rate (9/69 [13%]) and median durations of urinary catheter retention (37 hours; range, 3 to 172 hours) and hospitalization (3 days; range, 0.5 to 12 days) for the flush group did not differ significantly from the in-hospital UO recurrence rate (13/68 [19%]) and median durations of urinary catheter retention (36 hours; range, 1 to 117 hours) and hospitalization (3 days; range, 1 to 9 days) for the no-flush group. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that, for male cats with UO, urinary bladder lavage at the time of urethral catheterization had no significant effect on in-hospital recurrence rate of the condition, duration of urinary catheter retention, or duration of hospitalization; however, additional studies are necessary to validate or refute these findings.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 4-Refining and monitoring antithrombotic therapies.

OBJECTIVES: To systematically review the evidence for therapeutic monitoring of antithrombotic drugs in small animals, develop guidelines regarding antithrombotic monitoring, and identify knowledge gaps in the field. DESIGN: First, a standardized, systematic literature review was conducted to address predefined PICO (Population/Patient, Intervention, Control, Outcome) questions, with categorization of relevant articles according to level of evidence and quality. Preliminary guidelines were developed by PICO worksheet authors and the domain chair. Thereafter, a Delphi-style survey was used to develop consensus on guidelines regarding therapeutic monitoring of antithrombotics in dogs and cats. SETTING: Academic and referral veterinary medical centers. RESULTS: PICO questions regarding the utility of therapeutic monitoring were developed for 6 different antithrombotic drugs or drug classes, including aspirin, clopidogrel, warfarin, unfractionated heparin, the low molecular weight heparins, and rivaroxaban, The majority of the literature pertaining to therapeutic monitoring of antithrombotic drugs was either performed in experimental animal models of disease or involved studies of drug pharmacokinetics and pharmacodynamics in healthy laboratory animals. There was a paucity of high level of evidence studies directly addressing the PICO questions, which limited the strength of recommendations that could be provided. The final guidelines recommend that therapeutic monitoring should be performed when using warfarin or unfractionated heparin in dogs and cats at risk of thrombosis. There is insufficient evidence to make strong recommendations for therapeutic monitoring of aspirin or low molecular weight heparin in dogs and cats at this time. CONCLUSIONS: As in other CURATIVE domains, significant knowledge gaps were highlighted, indicating the need for substantial additional research in this field. Ongoing investigation of the role of therapeutic monitoring of antithrombotic therapies will undoubtedly facilitate improved outcomes for dogs and cats at risk of thrombosis.

American College of Veterinary Emergency and Critical Care (ACVECC) Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines: Small animal.

OBJECTIVES: To systematically review available evidence and establish guidelines related to the risk of developing thrombosis and the management of small animals with antithrombotics. DESIGN: Standardized, systematic evaluation of the literature (identified by searching Medline via PubMed and CAB abstracts) was carried out in 5 domains (Defining populations at risk; Defining rational therapeutic use; Defining evidence-based protocols; Refining and monitoring antithrombotic therapies; and Discontinuing antithrombotic therapies). Evidence evaluation was carried out using Population, Intervention, Comparison, Outcome generated within each domain questions to address specific aims. This was followed by categorization of relevant articles according to level of evidence and quality (Good, Fair, or Poor). Synthesis of these data led to the development of a series of statements. Consensus on the final guidelines was achieved via Delphi-style surveys. Draft recommendations were presented at 2 international veterinary conferences and made available for community assessment, review, and comment prior to final revisions and publication. SETTINGS: Academic and referral veterinary medical centers. RESULTS: Over 500 studies were reviewed in detail. Worksheets from all 5 domains generated 59 statements with 83 guideline recommendations that were refined during 3 rounds of Delphi surveys. A high degree of consensus was reached across all guideline recommendations. CONCLUSIONS: Overall, systematic evidence evaluations yielded more than 80 recommendations for the treatment of small animals with or at risk of developing thrombosis. Numerous significant knowledge gaps were highlighted by the evidence reviews undertaken, indicating the need for substantial additional research in this field.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 1-Defining populations at risk.

OBJECTIVES: Thrombosis is a well-recognized phenomenon in dogs and cats with a significant impact on morbidity and mortality. Despite growing awareness of thrombosis and increased use of antithrombotic therapy, there is little information in the veterinary literature to guide the use of anticoagulant and antiplatelet medications. The goal of Domain 1 was to explore the association between disease and thrombosis in a number of conditions identified as potential risk factors in the current veterinary literature, to provide the basis for prescribing recommendations. DESIGN: A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. Revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated included immune-mediated hemolytic anemia, protein-losing nephropathy, pancreatitis, glucocorticoid therapy, hyperadrenocorticism, neoplasia, sepsis, cerebrovascular disease, and cardiac disease. SETTINGS: Academic and referral veterinary medical centers. RESULTS: Of the diseases evaluated, a high risk for thrombosis was defined as dogs with immune-mediated hemolytic anemia or protein-losing nephropathy, cats with cardiomyopathy and associated risk factors, or dogs/cats with >1 disease or risk factor for thrombosis. Low or moderate risk for thrombosis was defined as dogs or cats with a single risk factor or disease, or dogs or cats with known risk factor conditions that are likely to resolve in days to weeks following treatment. CONCLUSIONS: Documented disease associations with thrombosis provide the basis for recommendations on prescribing provided in subsequent domains. Numerous knowledge gaps were identified that represent opportunities for future study.

The Essential Ectoenzyme SmNPP5 from the Human Intravascular Parasite Schistosoma mansoni is an ADPase and a Potent Inhibitor of Platelet Aggregation.

Schistosomes are intravascular parasitic platyhelminthes infecting > 200 million people globally and causing a debilitating disease, schistosomiasis. Despite the relatively large size of the adult worms and their disruption of blood flow, surprisingly, they do not appear to provoke thrombus formation around them in vivo. We hypothesize that proteins expressed at the host-parasite interface are key to this ability. Here, we functionally express an ectonucleotide pyrophosphatase/phosphodiesterase homologue, SmNPP5, that is expressed at the tegumental surface of intravascular Schistosoma mansoni. We report that SmNPP5, a known virulence factor for the worms, is a type one glycoprotein that cleaves the artificial substrate p-Nph-5'-TMP in a reaction that requires cations and at an optimal pH of 9. Using immunolocalization and enzyme activity measurements, we confirm that SmNPP5 is exclusively expressed at the host interactive surface of all intravascular life stages. SmNPP5 inhibits platelet aggregation in a dose-dependent manner, as measured by multiple electrode aggregometry (MEA) using whole blood. Inhibition is apparent when either collagen or adenosine diphosphate (ADP) is used as agonist but is lost following heat treatment of SmNPP5. Unlike its mammalian homologue, NPP5, the schistosome protein cleaves ADP and with a Km of 246 ± 34 µM. In sum, SmNPP5 is expressed in the intravascular environment where it can degrade ADP and act as an anticoagulant. In this manner, the protein likely helps limit blood clot formation around the worms in vivo to permit the parasites free movement within the vasculature.

Effect of transoral tracheal wash on respiratory mechanics in dogs with respiratory disease.

The purpose of this study was to determine the impact of a transoral tracheal wash (TOTW) on respiratory mechanics in dogs and to describe the use of a critical care ventilator (CCV) to determine respiratory mechanics. Fourteen client-owned dogs with respiratory diseases were enrolled. Respiratory mechanics, including static compliance (Cstat) and static resistance (Rstat), were determined before and after TOTW. Pre- and post-wash results were compared, with a P-value of < 0.05 considered significant. The mean ± standard deviation (SD) value of Cstat pre-TOTW was 1.59 ± 0.94 mL/cmH2O/kg while the mean ± SD of Cstat post-TOTW was 1.29 ± 0.71 mL/cmH2O/kg (P = 0.045). The median Rstat was not significantly different pre- and post-wash. The transoral tracheal wash altered respiratory mechanics, as observed by a reduction in Cstat, presumably due to airway flooding and collapse. While no long-lasting effects were noted in these clinical patients, this effect should be considered when performing TOTW on dogs with respiratory diseases. Respiratory mechanics testing using a CCV was feasible and may be a useful clinical testing approach.

L'objectif de cette étude était de déterminer l'impact d'un lavage transtrachéal (LTT) sur les méchanismes respiratoires chez le chien et de décrire l'utilisation d'un ventilateur de soins intensifs pour tester les méchanismes respiratoires. Quatorze chiens de compagnie atteints de maladies respiratoires ont été enrôlés. Les méchanismes respiratoires, incluant la conformité statique et la résistance statique, ont été déterminés avant et après un LTT. Les résultats pré- et post-lavage ont été comparés, en utilisant une valeur P < 0,05 comme significative. La moyenne ± écart type de Cstat pre-TOTW était 1,59 ± 0,94 mL/cmH2O/kg alors que la moyenne ± écart type de Cstat post-TOTW était 1,29 ± 0,71 mL/cmH2O/kg. (P = 0,045). Les médianes de Rstat pré- et post-lavage ne diffèrent pas de façon significative. Le lavage transtrachéal a altéré les mécanismes respiratoires, caractérisé par une réduction de Cstat, possiblement due à l'encombrement et au collapse des voies respiratoires. Cet effet temporaire chez nos patients devrait être considéré lors de l'utilisation de cette procédure chez des patients avec des troubles respiratoires. L'utilisation du ventilateur de soins intensifs pour le test des mécanismes respiratoires est faisable et peut être utile en clinique.(Traduit par les auteurs).

Severe brachycephalic obstructive airway syndrome is associated with hypercoagulability in dogs.

We evaluated whether dogs with severe brachycephalic obstructive airway syndrome (BOAS) developed a hypercoagulable state similar to people with obstructive sleep apnea. Five dogs with grade 3 BOAS were included as well as 5 healthy control Labrador Retrievers. Venous blood samples were collected from each dog for performance of thromboelastography and determination of hematocrit and platelet count. Groups were compared using a t-test, with p < 0.05 considered significant. Thromboelastography results identified that all BOAS dogs were hypercoagulable compared to the Labradors, having significantly shortened clotting time with increased angle, maximal amplitude, and clot rigidity. BOAS dogs also had evidence of delayed fibrinolysis. These results are consistent with, but more severe than, those previously documented in apparently healthy Bulldogs. Together, these findings support the presence of a hypercoagulable state in brachycephalic dogs, and suggest that this state is amplified by increasing severity of BOAS.

Assessment of hemostatic changes in a model of acute hemorrhage in dogs.

OBJECTIVE: To evaluate hemostatic changes following experimental acute hemorrhage in dogs using traditional coagulation tests (eg, platelet count, prothrombin time [PT], and activated partial thromboplastin time [aPTT]), kaolin-activated thromboelastography (TEG), and whole blood multiple electrode impedance platelet aggregometry. DESIGN: Prospective study. SETTING: Research laboratory. ANIMALS: Five Beagles. INTERVENTIONS: Dogs were anesthetized prior to obtaining blood samples for baseline PCV, total plasma protein (TPP), arterial blood-gas, platelet count, PT, aPTT, TEG, fibrinogen, and aggregometry. Blood was obtained at 4 additional time points, following 20% blood volume loss, 40% blood volume loss, 60 minutes of sustained hypotension, and after autologous blood transfusion. In addition, heart rate and direct arterial blood pressure were measured at each time point. MEASUREMENTS AND MAIN RESULTS: Significant decreases were noted for PCV (P = 0.048), TPP (P < 0.0001), and arterial blood pressures (P < 0.0001) over time. Platelet count did not change significantly (P = 0.879), but platelet function was decreased following hemorrhage when arachidonic acid (P = 0.004) and ADP (P = 0.008) were used as agonists. The TEG variables R (P = 0.030), MA (P = 0.043), and G (P = 0.037) were significantly, albeit mildly, changed following hemorrhage. Significant prolongations in PT (P < 0.0001) and aPTT (P = 0.041), and decreases in fibrinogen concentration (P = 0.002) were also seen. CONCLUSION: Platelet dysfunction occurred following hemorrhage in this model, despite a stable platelet count. Additionally, significant changes associated with hemorrhage were documented in aPTT, fibrinogen, and MA. Platelet function testing in dogs with naturally occurring hemorrhage warrants further investigation.

Effects of in vitro hemodilution with crystalloids, colloids, and plasma on canine whole blood coagulation as determined by kaolin-activated thromboelastography.

OBJECTIVE: To investigate the effects of in vitro hemodilution with lactated Ringers solution (LRS), hetastarch (HES), and fresh frozen plasma (FFP) on whole blood coagulation in dogs as assessed by kaolin-activated thromboelastography. DESIGN: In vitro experimental study. SETTING: University teaching hospital. ANIMALS: Six healthy client-owned dogs. INTERVENTIONS: Whole blood was collected and diluted in vitro at a 33% and 67% dilution with either LRS, HES, or FFP. MEASUREMENTS AND MAIN RESULTS: Kaolin-activated thromboelastography was performed on each sample as well as a control. Thromboelastographic parameters R (min), alpha (deg), K (min), and MA (mm) were measured and compared to the sample control for each dilution using mixed model methodology. Prolongation in coagulation times were seen at both dilutions with LRS and HES. There was no significant difference in R times at the 33% dilution, but R time was significantly prolonged at the 67% dilution with HES (P = 0.004). MA was significantly decreased for LRS at both dilutions (P = 0.013, P < 0.001) and more profoundly decreased for HES (P < 0.001, P = 0.006). No significant difference in any parameter was found for FFP. CONCLUSIONS: In vitro hemodilution of whole blood with both LRS and HES but not FFP resulted in significant effects on coagulation with HES having a more profound effect. In vivo evaluation of changes in coagulation with various resuscitation fluids is warranted and may be clinically relevant.

Clinical experience of anti-Xa monitoring in critically ill dogs receiving dalteparin.

OBJECTIVES: To describe a population of critically ill dogs receiving dalteparin monitored with an anti-Xa assay, to assess the potential utility of serial monitoring, and to investigate the association between pre-treatment thromboelastography (TEG) and the ability to achieve targeted anti-Xa activity. DESIGN: Descriptive retrospective study. SETTING: Veterinary teaching hospital. ANIMALS: Thirty-eight client-owned dogs receiving dalteparin and monitored with an anti-Xa assay. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were retrospectively reviewed for signalment, underlying disease, clinicopathological data, occurrence of thromboembolic events, complications, and outcome. Thirty-eight dogs receiving dalteparin were monitored with an anti-Xa assay. Diseases included hematological disease, protein-losing disease, neoplastic disease, and septic processes. Pretreatment hypercoagulability was present in 34/35 dogs by assessment of TEG. Five cases of thromboembolism were confirmed prior to starting treatment and 4 cases occurred during hospitalization. Bleeding complications were rare (3/38) and 29/38 dogs survived to discharge. Interpretation of the anti-Xa assay allowed for dose adjustment although reliable achievement of target anti-Xa activity was not demonstrated. Dogs with higher G values on pretreatment TEG were significantly less likely to achieve the target anti-Xa activity (ie, be above or below the target range). CONCLUSIONS: Dalteparin was well tolerated in a heterogeneous population of dogs. However, dose adjustment in response to anti-Xa activity interpretation inconsistently resulted in subsequent attainment of the target anti-Xa range. Development of guidelines may be warranted to more consistently achieve the target range. Dogs that appear more hypercoagulable on pre-treatment TEG may require closer monitoring and greater dose adjustment to achieve the target anti-Xa range.

Systematic evaluation of evidence on veterinary viscoelastic testing part 3: Assay activation and test protocol.

OBJECTIVE: To systematically examine the evidence on activating agents and test protocols for the thrombelastography (TEG) and rotational thrombelastometry (ROTEM) viscoelastic point-of-care instruments and to identify knowledge gaps. DESIGN: Ten questions were considered, the primary question addressed the use of activating agents and secondary questions addressed assay temperature, length of analysis, pipetting, sample volume, reproducibility, and quality controls. Standardized, systematic evaluation of the literature was performed. Relevant articles were categorized according to level of evidence (LOE). Consensus was developed regarding conclusions for application of concepts to clinical practice. SETTING: Academic and referral veterinary medical centers. RESULTS: PubMed and CAB abstracts were searched. Twenty papers were initially identified concerning the primary question; 16 were in support of the questions (LOE 2 Good, LOE 3 Good, LOE 5 Good, LOE 6 Good, LOE 5 Fair, LOE 6 Fair); and 4 were neutral (LOE 3 Good, LOE 6 Good, LOE Fair, LOE 5 Fair). Additional papers were evaluated post hoc during manuscript preparation. CONCLUSIONS: Overall, there is a body of evidence from veterinary and human medicine that strongly suggests that TEG or ROTEM assays using citrated samples that employ an activator have significantly lower inherent variability than those that use recalcification alone. There is also strong evidence in dogs, cats, and humans that the results obtained using different activators are not directly comparable. There is no evidence to suggest that any one activating agent is superior to another for all patient populations, or drug monitoring indications. As such, use of more than one assay for complete thromboelastographic evaluation of a patient's coagulation system may be warranted. Standardization of the concentrations of activators would be beneficial.

Iatrogenic water intoxication in two cats.

OBJECTIVE: To describe 2 cats that developed acute iatrogenic water intoxication, one associated with a continuous infusion of water provided via an esophagostomy tube and one following SC administration of 5% dextrose in water (D5W). CASE OR SERIES SUMMARY: A 10-year-old cat with squamous cell carcinoma was hospitalized for treatment of dehydration. Rehydration was provided with water via an esophagostomy tube at 5.7 mL/kg/h. After 30 hours of therapy, the cat was found dull and weak. Serum sodium was markedly decreased at 116 mmol/L (116 mEq/L). Supplemental water was stopped, and IV furosemide and mannitol were provided to eliminate free water. Hypertonic saline (1.5%) was administered IV to rapidly restore the sodium concentration. The serum sodium concentration corrected over 17 hours, and the cat was discharged without neurological complications. The second cat had previously received 300 mL D5W subcutaneously and represented 8 hours later with lethargy and paresis with a serum sodium level of 126 mmol/L (126 mEq/L). Intravenous fluid therapy was provided using 0.9% NaCl. Over the following day, the cat's mentation and paresis resolved and sodium concentrations normalized. NEW OR UNIQUE INFORMATION PROVIDED: These 2 cases describe a presumed uncommon iatrogenic complication of severe hyponatremia due to water provided either via an esophagostomy tube or subcutaneously. While oral rehydration is often considered ideal, it may result in signs of water intoxication if not carefully monitored; additionally, D5W is never considered an acceptable fluid choice as a SC bolus. If promptly recognized, acute hyponatremia may be corrected rapidly with no lasting consequences.