Investigation of Platelet Function Analyzer 200 platelet function measurements in healthy cats and cats receiving clopidogrel.

The Platelet Function Analyzer 200 (PFA-200; Siemens) is an in vitro substitute for in vivo bleeding time that is designed to investigate platelet function in a more physiologic manner than traditional aggregometry. The analyzer reports a closure time (CT) as a marker of platelet function, and may also report the calculated platelet function measurement primary hemostasis components, PHC1 and PHC2. These incorporate the measured total volume (TV) of blood aspirated and the initial flow rate (IF). We determined, for the COL/ADP and P2Y cartridges, the median total volume (TVmedian), and RIs for CT, IF, TV, PHC1, and PHC2, and investigated the sensitivity and specificity of those parameters at the determined interpretation thresholds in determination of the clopidogrel effect. Healthy client-owned cats were recruited prospectively to determine RIs for CT, IF, TV, PHC1, and PHC2. Healthy blood-donor cats and cats on clopidogrel therapy were included retrospectively to determine test performance. In 20 healthy cats, RIs for COL/ADP were CT (19.5-87.2 s), IF (199-278 µL/min), TV (199-332 µL), PHC1 (94-106%), and PHC2 (52-148%); and for P2Y, CT (4.2-94.3 s), IF (112-208 µL/min), TV (151-294 µL), PHC1 (35-178%), and PHC2 (90-109%). CVs were calculated for all of these values. Specificity for detection of the clopidogrel effect was calculated from a group of healthy blood donors, and sensitivity for detection of the clopidogrel effect from a group of cats with known clopidogrel effect. Sensitivity and specificity were, for COL/ADP: CT (83.3%, 66.6%), IF (41.4%, 83.3%), TV (83.3%, 100%), PHC1 (100%, 100%) and PHC2 (100%, 83.3%); and for P2Y: CT (100%, 94.4%), IF (30%, 44.4%), TV (100%, 94.4%), PHC1 (100%, 100%), and PHC2 (100%, 97.7%). These PFA-200 values may be beneficial in the determination of platelet function in cats.

Validation of storage and shipping of feline blood samples for analysis on the Platelet Function Analyzer-200 for determining the effect of clopidogrel.

BACKGROUND: The Platelet function analyzer-200 (PFA-200) can determine the effect of clopidogrel in cats, but analysis traditionally must be performed at point-of-care (POC). The ability to ship samples of blood to a laboratory would allow widespread access. OBJECTIVES: We aimed to validate the shipping of blood samples for PFA-200 analysis in cats to determine the effect of clopidogrel. METHODS: Twenty healthy cats and 10 cats receiving clopidogrel were recruited. Blood was collected from cats and aliquoted into two samples, one was analyzed at POC within 2 hours using the PFA-200, and the other was packaged and transported to a location 4 km away, stored, and transported back to the lab for analysis the following day. RESULTS: Median closure times (CTs) with the collagen/adenosine diphosphate (COL/ADP) cartridge in healthy cats were 51.5 seconds (POC) and 78.8 seconds (shipped), which were significantly different (P < 0.001), and for cats on clopidogrel, median CTs were 147.5 seconds (POC) and 190 seconds (shipped), which were not significantly different (P = 0.131). Median CTs with the P2Y cartridge in healthy cats were 50.5 seconds (POC) and 64.9 seconds (shipped), which were significantly different (P = 0.03), and in cats receiving clopidogrel, median CTs were 300 seconds (POC) and 300 seconds (shipped) which were not significantly different (P = 1.000). Reference intervals for CTs differed for COL/ADP at POC (19.8-89.7 seconds) and shipped (50.9-161.6 seconds) and for P2Y at POC (35.5-118.8 seconds) and shipped (35.1-108.9 seconds). Receiver operating characteristics showed similar areas under the curve (AUCROCs) regarding the effect of clopidogrel for COL/ADP at POC (0.994 seconds) and shipped (0.932) and for P2Y at POC (0.904 seconds) and shipped (0.975 seconds). When classifying for the presence of clopidogrel effects, Cohen's Kappa was 0.62 for COL/ADP and 1.00 for P2Y. CONCLUSIONS: Shipping blood samples for PFA analysis are feasible with similar performance to POC analyses for determining the effect of clopidogrel in cats.

Platelet function analyzer-200 closure curve analysis and assessment of flow-obstructed samples.

BACKGROUND: The Platelet function analyzer-200 can determine the effect of clopidogrel in cats. Flow obstruction is an error that causes uninterpretable results. Closure curves and parameters initial flow rate (IF) and total volume (TV) are displayed by the PFA-200 and may allow interpretation of results in cases of flow obstruction. The primary hemostasis components (PHC) are calculated values that normalize these parameters. OBJECTIVES: To determine if closure curves and research parameters allow detecting the effect of clopidogrel in cases of flow obstruction. METHODS: A review of closure curves identified those with flow obstruction and paired analysis that did not. Non-flow-obstructed curves were used to categorize curves with respect to clopidogrel effects. IF, TV, PHC(1), and PHC(2) were evaluated to determine if these could be used to categorize if a sample exhibited the effects of clopidogrel. Curves were visually analyzed, and characteristics identified that were more common with or without the effect of clopidogrel. Visual analysis of curves was performed by blinded observers to determine if a visual analysis was able to predict the effect of clopidogrel. RESULTS: Analysis of parameters was able to predict closure or non-closure in flow-obstructed curves. TV, PHC(1), and PHC(2) had area under the curve of the receiver operating characteristics of 0.79, 0.79, and 0.87. Visual curve analysis was unable to predict closure, with an average accuracy of only 55%, among three reviewers. Agreement between reviewers was poor (Fleiss' Kappa 0.06). CONCLUSIONS: Visual curve analysis was unable to determine the effect of clopidogrel in flow-obstructed samples. Numerical parameters were able to detect the effect of clopidogrel with a high degree of accuracy in flow-obstructed samples.

Validation of Plateletworks ADP for the ProCyte Dx analyzer.

BACKGROUND: Platelet function testing in cats allows determination of clopidogrel effect. Plateletworks assesses aggregation based on decreasing platelet counts on hematology analyzers in response to agonists. It has not been validated for the IDEXX ProCyte Dx analyzer. Ideal time to perform analysis and the utility of other platelet parameters have not been fully assessed. OBJECTIVES: To validate Plateletworks ADP on the ProCyte Dx, to investigate the utility of various platelet parameters using Plateletworks ADP, and determine the ideal time to perform analysis. ANIMALS: Twenty healthy cats recruited from the general population used for transference of reference intervals to a new analyzer, and 10 cats receiving clopidogrel to determine clopidogrel effect. METHODS: Plateletworks ADP using the ProCyte Dx and ADVIA 2120i analyzer was run simultaneously in both healthy cats and cats receiving clopidogrel, and CBC results at different timepoints were compared between analyzers. RESULTS: Aggregation was significantly different (P < .001) between analyzers. Cohen's kappa showed almost perfect agreement for determination of clopidogrel effect, and the area under the curve of the receiver operating characteristic was 1.0. Lower limits of the aggregation reference interval in healthy cats were 28.8% on the ProCyte Dx and 12.5% on the ADVIA 2120i. Coefficients of variation for platelet parameters were not different between analyzers. No significant changes in mean platelet volume, plateletcrit, large platelets, and mean platelet component were identified. No significant change in aggregation was observed within the first hour after phlebotomy. CONCLUSIONS AND CLINICAL IMPORTANCE: Our study validated the Plateletworks ADP system on the ProCyte Dx analyzer. Samples may be analyzed up to 1 h after collection.

Diagnostic and public health investigation of Mycobacterium tuberculosis infection in a dog in Ontario, Canada.

A 4-y-old, female mixed-breed dog was presented to the Ontario Veterinary College for further evaluation of multiple pulmonary and hepatic masses, intrathoracic lymphadenitis, and recent development of a pyogranulomatous pleural effusion. Along with other comprehensive tests, a thoracic lymph node biopsy was performed, and Mycobacterium tuberculosis complex infection was confirmed by real-time PCR. The dog's condition declined post-operatively, and euthanasia was elected. Postmortem examination confirmed severe granulomatous pneumonia, hepatitis, intrathoracic and intraabdominal lymphadenitis, omentitis, and nephritis. Line-probe assays performed on samples collected postmortem confirmed the species as M. tuberculosis. 24-loci MIRU-VNTR genotyping, spoligotyping, and whole-genome sequencing revealed relations to known human isolates, but no epidemiologic link to these cases was investigated. Given the concern for potential human exposure during this animal's disease course, a public health investigation was initiated; 45 individuals were tested for M. tuberculosis exposure, and no subsequent human infections related to this animal were identified. Our case highlights the need for more readily available, minimally invasive testing for the diagnosis of canine mycobacteriosis, and highlights the ability of canid species to act as potential contributors to the epidemiology of M. tuberculosis infections.

Accuracy of point-of-care crossmatching methods and crossmatch incompatibility in critically ill dogs.

BACKGROUND: The performance of commercial point-of-care crossmatch (CM) tests compared to laboratory tube agglutination CM is unknown. Additionally, there is limited information regarding CM incompatibility in ill dogs. OBJECTIVES: To determine if point-of-care major CM methods are accurate in detecting compatible and incompatible tests when compared to laboratory CM methods, and to identify factors associated with CM incompatibility in dogs. ANIMALS: Part 1 (prospective) included 63 client-owned dogs potentially requiring blood transfusion. Part 2 (retrospective) included all dogs from part 1, plus medical records of 141 dogs with major CM results. METHODS: For part 1, major CM was performed using a tube agglutination assay (LAB-CM), a gel-based point-of-care test (GEL-CM), and an immunochromatographic point-of-care test (IC-CM). For part 2, medical record data were collected to determine rates of and risk factors for CM incompatibility. RESULTS: Kappa agreement between the LAB-CM and GEL-CM methods could not be calculated due to a relative lack of incompatible results. Kappa agreement between the LAB-CM and IC-CM methods was 0.16 (95% confidence interval [CI] = 0-0.31, P = .007) indicating no agreement. The LAB-CM incompatibility in transfusion-naïve vs dogs that had a transfusion was 25% and 35%, (P = .3). CONCLUSIONS AND CLINICAL IMPORTANCE: Compared to laboratory methods, point-of-care methods evaluated in our study lacked sensitivity for detecting incompatibilities. Dogs had similar rates of major CM incompatibility regardless of transfusion history. This suggests CM testing prior to transfusion be considered in all dogs however our study did not investigate clinical relevancy of incompatible LAB-CM.

A pilot study evaluating the effects of prestorage leukoreduction on markers of inflammation in critically ill dogs receiving a blood transfusion.

OBJECTIVES: To compare markers of inflammation after transfusion of leukoreduced (LR) packed RBCs (pRBCs) versus non-LR pRBCs in dogs with critical illness requiring blood transfusion, and to report survival to discharge and rates of transfusion reactions in these dogs. DESIGN: Prospective randomized blinded clinical study June 2014-September 2015. SETTING: University veterinary teaching hospital. ANIMALS: Twenty-three client-owned critically ill dogs, consecutively enrolled. INTERVENTIONS: Dogs requiring a single pRBC transfusion were randomized into the LR or non-LR pRBC group. Exclusion criteria included: requirement for multiple blood products, history of previous blood transfusion, and administration of anti-inflammatory or immunosuppressive medication prior to enrollment. MEASUREMENTS: Blood samples were obtained immediately prior to transfusion, then 2 and 24 hours following transfusion. Parameters measured at each time point included: PCV, WBC count, segmented and band neutrophil counts, fibrinogen, and plasma lactate and C-reactive protein concentrations. Acute patient physiologic and laboratory evaluation fast score was calculated on admission. RESULTS: Eleven dogs were included in the LR group and 12 in the non-LR group; scores of illness severity were not significantly different between groups. Total WBC count was significantly higher in the non-LR versus LR group 24 hours following pRBC transfusion, but this difference was not evident 2 hours following transfusion. No other inflammatory parameters at any time point were significantly different between LR versus non-LR pRBC transfused dogs. Survival rates to discharge for LR and non-LR groups were 8/11 and 9/12, respectively. Acute transfusion reactions were identified in 1/11 and 2/12 dogs in the LR and non-LR group, respectively. All transfused blood was stored ≤12 days. CONCLUSIONS: Most markers of inflammation did not significantly increase following transfusion of LR versus non-LR pRBCs stored ≤12 days in ill dogs. Further prospective, randomized trials are needed in clinically ill dogs to determine the benefit of prestorage leukoreduction.

Comparison of bronchoscopic and nonbronchoscopic bronchoalveolar lavage in healthy cats.

OBJECTIVE To compare bronchoalveolar lavage (BAL) accomplished by use of a bronchoscopic (B-BAL) and a nonbronchoscopic (NB-BAL) technique in healthy cats. ANIMALS 12 healthy cats. PROCEDURES Two BALs were performed in a randomized order 2 weeks apart in each cat. Cats were anesthetized, and a 2.9-mm fiberoptic bronchoscope (B-BAL) or 8F red rubber catheter (NB-BAL) was wedged in a bronchus. Two 5-mL aliquots of saline (0.9% NaCl) solution were infused into the left and right caudal lung fields and aspirated manually with a 20-mL syringe. Proportion of BAL fluid (BALF) retrieved, depth of wedging, and anesthetic complications were recorded. Total nucleated cell count, differential cell count, and semiquantitative scores of cytologic slide quality were determined for all BALF samples. Results were compared with ANOVAs and Wilcoxon signed rank tests. RESULTS Proportion of retrieved BALF and depth of wedging were significantly greater for B-BAL than NB-BAL. Differential cell counts and cytologic slide quality did not differ significantly between techniques. Complications included transient hemoglobin desaturation (24/24 [100%] BALs) and prolonged anesthetic recovery time (4/24 [17%] BALs). Anesthetic recovery scores did not differ significantly between techniques. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that NB-BAL was noninferior to B-BAL with regard to ease of performance, anesthetic variables, and cytologic slide quality for cats without clinical respiratory tract disease.

Prevalence of antinuclear and anti-erythrocyte antibodies in healthy cats.

BACKGROUND: Positive antinuclear antibody and direct antiglobulin tests support diagnoses such as systemic lupus erythematosus and immune-mediated anemia, respectively. Positive tests may occur in cats, but the prevalence of positive results in healthy cats is not well known. OBJECTIVE: The study's purpose was to determine prevalences of positive antinuclear antibody and direct antiglobulin tests in healthy cats. METHODS: Antinuclear antibody titers were measured by indirect immunofluorescence, and anti-erythrocyte antibodies were measured by the microtitration direct antiglobulin test at 37, 23, and 4°C in 61 client-owned and 28 facility-owned cats. Differences between the 2 groups were examined using chi-squared tests. RESULTS: For the antinuclear antibody tests, 70% of client-owned cats were negative, 10% had weak titers (1:40-1:80), and 20% had strong titers (1:160-1:320). Facility-owned cats had significantly fewer positive titers with 96% negative and one positive (1:8). For the antiglobulin test at 37°C, 93% of all cats were negative, 2 cats in each group were positive at low dilutions (1:2), and 2 client-owned cats were transiently positive at high dilutions (≥ 1:2048). At 23°C, 90% of all cats were negative, and 2 client-owned and 5 facility-owned cats were positive at low dilutions (1:2-1:8). At 4°C, 67% of client-owned cats had invalid results (negative control well agglutination), and 33% had negative results, while of facility-owned cats 14% had invalid results, 14% had agglutination at low dilutions, and 72% were negative. CONCLUSION: Healthy cats may have positive antinuclear antibody and direct antiglobulin tests, but the prevalence of strong reactions is low.

Assessment of platelet function in healthy sedated cats using three whole blood platelet function tests.

The objectives of this study were to establish feline references intervals for 3 commercial whole blood platelet function test analyzer systems: Multiplate analyzer (MP; Roche Diagnostics International Ltd., Rotkreuz, Switzerland), Platelet Function Analyzer-100 (PF: Siemens Canada, Mississauga, Ontario, Canada), and Plateletworks Combo-25 kit (PW; Helena Laboratories, Beaumont, TX). Venipuncture was performed on 55 healthy sedated cats, and platelet aggregation in response to adenosine diphosphate (ADP), collagen (COL), and arachidonic acid (AA; MP only) was assessed using citrated blood. For the MP analyzer, median (95% confidence intervals [CIs]) area under curve (Units) for ADP, COL, and AA agonists were 87 (11-176), 81 (32-129), and 91 (59-129), respectively. For the PF analyzer, median (95% CIs) closure time, using COL-ADP cartridges, was 69 (46-89) sec. For the PW assay, median (95% CIs) percent aggregations for ADP and COL agonists were 71 (18-92) and 49 (9-96), respectively, using impedance hematology analyzer platelet counts, and 94 (25-98) and 68 (14-119), respectively, using flow cytometry hematology analyzer platelet counts. There were low correlations between the PF analyzer (COL-ADP cartridge) and MP analyzer (COL agonist; ρ = 0.11), and between the PF analyzer (COL-ADP cartridge) and PW assay (COL agonist using impedance platelet counts; ρ = 0.14). The PW assay percent aggregations using impedance and flow cytometric platelet counts were correlated for both ADP (ρ = 0.64) and COL (ρ = 0.64) agonists. Platelet function testing using these tests are feasible in cats, but 95% CIs are wide, so single results may be difficult to interpret. Platelet counting by impedance or flow cytometry may be used for the PW assay but are not interchangeable.

Protothecosis in a dog.

A case of a disseminated algal infection is reported in a young rough-coated collie dog with progressive neurologic deficits, blindness, and hemorrhagic diarrhea. Prototheca zopfii organisms were cultured from feces, urine, and blood. At necropsy, granulomas containing typical organisms were identified within the proximal colon, heart, kidneys, and eyes.

Protothécose chez un chien. Un cas d'infection algoïde est signalé chez un jeune chien Collie à poil court avec des troubles neurologiques progressifs, de la cécité et de la diarrhée hémorragique. Des organismes de type Prototheca zopfii ont été cultivés à partir des fèces, de l'urine et du sang. À la nécropsie, des granulomes contenant des organismes typiques ont été identifiés dans le côlon proximal, le cœur, les reins et les yeux.(Traduit par Isabelle Vallières).

Comparison of feline core bone marrow biopsies from different sites using 2 techniques and needles.

BACKGROUND: Commonly used 11ga or 13ga biopsy needles are relatively large for cats and often preclude successful collection of bone marrow (BM) core biopsies. OBJECTIVES: The objective was to compare 15ga to 13ga BM core biopsy ease of collection and specimen quality. METHODS: In 10 cats, humeral biopsies obtained with 15ga EZ-IO needles were compared with iliac biopsies obtained with 13ga Jamshidi needles. Body condition, ease of collection, section quality, postprocedure pain, and swelling at biopsy sites were scored. Specimen length on mounted slides was measured and specimens with quality scores of 3-5 out of a maximum value of 5 were considered to be of acceptable diagnostic quality. The distribution of all parameters was assessed by Shapiro-Wilk tests, and differences in parameters were assessed by ANCOVA. RESULTS: There were no significant differences between 15ga and 13ga biopsies, except that the 15ga humeral biopsy was judged to be easier to perform than 13ga iliac biopsy, and there was more severe postbiopsy swelling with 13ga biopsies. Facility score (mean ± SD), section quality score (median ± SD) and specimen length (mm, mean ± SD) were 12.7 ± 2.3, 2.0 ± 1.4, and 6.0 ± 2.1 for 15ga biopsies, respectively, and 8.9 ± 2.4, 1.0 ± 1.8, and 7.5 ± 2.5 for 13ga biopsies, respectively. Three specimens of acceptable quality were obtained with each 15ga and 13ga biopsies. CONCLUSIONS: In cats, BM biopsy of the humerus with a 15ga needle is easier and causes less postbiopsy swelling than biopsy of the ilium with a 13ga needle. Sites and needles are equivalent with respect to yielding specimens of acceptable quality. Neither technique consistently captured high-quality specimens.

Comparison of bronchoalveolar lavage fluid obtained by manual aspiration with a handheld syringe with that obtained by automated suction pump aspiration from healthy dogs.

OBJECTIVE: To compare bronchoalveolar lavage (BAL) fluid obtained by manual aspiration (MA) with a handheld syringe with that obtained by suction pump aspiration (SPA) in healthy dogs. ANIMALS: 13 adult Beagles. PROCEDURES: Each dog was anesthetized and bronchoscopic BAL was performed. The MA technique was accomplished with a 35-mL syringe attached to the bronchoscope biopsy channel. The SPA technique was achieved with negative pressure (5 kPa) applied to the bronchoscope suction valve with a disposable suction trap. Both aspiration techniques were performed in each dog in randomized order on opposite caudal lung lobes. Two 1 mL/kg aliquots of warm saline (0.9% NaCl) solution were infused per site. For each BAL fluid sample, the percentage of retrieved fluid was calculated, the total nucleated cell count (TNCC) and differential cell count were determined, and semiquantitative assessment of slide quality was performed. Comparisons were made between MA and SPA techniques for each outcome. RESULTS: 1 dog was removed from the study because of illness. The mean percentage of fluid retrieved (mean difference, 23%) and median TNCC (median distribution of differences, 100 cells/µL) for samples obtained by SPA were significantly greater than those for samples obtained by MA. CONCLUSIONS AND CLINICAL RELEVANCE: In healthy dogs, BAL by SPA resulted in a significantly higher percentage of fluid retrieval and samples with a higher TNCC than did MA. Further evaluation of aspiration techniques in dogs with respiratory tract disease is required to assess whether SPA improves the diagnostic yield of BAL samples.

Comparison of a gel column blood typing method and a point-of-care cartridge for dog erythrocyte antigen 1.1.

BACKGROUND: Blood typing for the presence of Dog Erythrocyte Antigen (DEA) 1.1 is recommended in all donor and recipient dogs prior to transfusion of blood products. The objective of this study was to determine if a point-of-care DEA 1.1 blood typing cartridge could be used in place of the gel column typing method. STUDY DESIGN: Detection of DEA 1.1 was performed using a laboratory-based gel column method and a point-of-care cartridge. A convenience sample of 30 healthy blood donors, 13 dogs with immune-mediated hemolytic anemia (IMHA) (3 of which had concurrent immune-mediated thrombocytopenia [IMT]), and 44 dogs with other diseases was included in the study. KEY FINDINGS: Agreement was observed between the tests for normal dogs and dogs with nonimmune-mediated disease in 74/74 cases. Two dogs in the IMHA group had indeterminate gel column blood typing results; 1 dog in this group had a negative gel column test result but a positive cartridge test result. SIGNIFICANCE: There was good agreement between the 2 methods for normal dogs and dogs with nonimmune-mediated disease. Blood typing methods in dogs with IMHA should be further investigated.

Comparison between manual aspiration via polyethylene tubing and aspiration via a suction pump with a suction trap connection for performing bronchoalveolar lavage in healthy dogs.

OBJECTIVE: To compare the diagnostic quality of bronchoalveolar lavage (BAL) fluid acquired from healthy dogs by manual aspiration via polyethylene tubing (MAPT) and via suction pump aspiration (SPA) with a suction trap connection. ANIMALS: 12 healthy adult Beagles. PROCEDURES: BAL was performed with bronchoscopic guidance in anesthetized dogs. The MAPT was performed with a 35-mL syringe attached to polyethylene tubing wedged in a bronchus via the bronchoscope's biopsy channel. The SPA was performed with 5 kPa of negative pressure applied to the bronchoscope's suction valve via a suction trap. The MAPT and SPA techniques were performed in randomized order on opposite caudal lung lobes of each dog. Two 1 mL/kg lavages were performed per site. Samples of BAL fluid were analyzed on the basis of a semiquantitative quality scale, percentage of retrieved fluid, and total nucleated and differential cell counts. Results were compared with Wilcoxon signed rank tests. RESULTS: Percentage of BAL fluid retrieved (median difference, 16.2%), surfactant score (median difference, 1), and neutrophil count (median difference, 74 cells/µL) were significantly higher for SPA than for MAPT. A higher BAL fluid epithelial cell score was obtained via MAPT, compared with that for samples obtained via SPA (median difference, 1). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that in healthy dogs, SPA provided a higher percentage of BAL fluid retrieval than did MAPT. The SPA technique may improve the rate of diagnostic success for BAL in dogs, compared with that for MAPT. Further evaluation of these aspiration techniques in dogs with respiratory tract disease is required.

Comparison of citrated native and kaolin-activated samples for thrombelastographic analysis in healthy dogs.

BACKGROUND: Thrombelastographic (TEG) analysis is a test of global hemostasis in veterinary medicine; however, there have been limited comparisons of analysis of citrated native and kaolin-activated samples. OBJECTIVES: The purpose of this study was to determine the variation in TEG variables between citrated native and kaolin-activated whole blood samples and to establish reference intervals for both sample types. METHODS: Citrated whole blood samples were obtained from 40 healthy dogs. Thirty minutes after collection, TEG analysis was performed simultaneously on samples with and without kaolin-activation. Reaction time (R), clotting time (K), angle (α), maximum amplitude (MA), global clot strength (G), and clot lysis at 30 minutes (LY30) were recorded, and the concordance correlation coefficient (ρ(c)) was calculated for each sample type. RESULTS: Significant differences between results obtained for kaolin-activated and native samples were obtained for R (mean difference -1.3 minute, P = .0009), K (-0.7 minute, P = .0003), α (+5.1º, P = .002), MA (+2.4 mm, P = .002), and G (+568 dyn/cm(2), P = .0009). LY30 was not different between methods. There was substantial agreement between methods for G (ρ(c) = .69) and MA (ρ(c) = .65), moderate agreement for R (ρ(c) = .45) and α (ρ(c) = .44), fair agreement for K (ρ(c) = .29), and slight agreement for LY30 (ρ(c) = .04). CONCLUSIONS: The TEG variables were significantly altered by kaolin activation; however, some agreement between sample types suggests a consistent bias. In citrated whole blood activated with kaolin, clot formation time is shortened and the amplitude of the tracing is increased, resulting in a TEG tracing that appears to indicate relative hypercoagulability compared with that obtained using native citrated whole blood samples.

Comparison of canine core bone marrow biopsies from multiple sites using different techniques and needles.

BACKGROUND: Commonly used 11 or 13ga needles are relatively large for collection of bone marrow (BM) biopsies from small dogs. OBJECTIVES: The aims of this study were to assess ease of BM collection and quality of specimens obtained from small dogs using 13 and 15ga needles and to determine if specimen encasement would improve quality. METHODS: Humeral and iliac biopsies obtained from 17 Beagle dogs with a 15ga needle and a power driver were compared with humeral biopsies obtained with a 13ga Jamshidi needle. Ease of collection (scored as 1 [very difficult] to 5 [very easy] for 3 components of collection with scores summed), section quality (scored as 1 [poor] to 5 [good]), and lesions at collection sites were scored. Quality of additional humeral biopsies obtained with a 15ga needle and wrapped in tissue paper prior to fixation was assessed. RESULTS: Use of a 15ga needle to obtain a humeral BM biopsy was significantly easier (mean score ± SD = 13.6 ± 1.7) than obtaining humeral BM using a 13ga needle (11.4 ± 1.6; P < .001) or obtaining iliac BM using a 15ga needle (10.9 ± 2.0, P < .001). Quality of humeral biopsies obtained with a 13ga needle (3.9 ± 1.2) was better than for biopsies of the humerus (1.9 ± 1.3, P < .001) or ilium (1.4 ± 0.6, P < .001) using a 15ga needle. Only sites sampled with a 13ga needle were identifiable grossly after the procedure. In most biopsies, cell density and cellularity were lower when a 15ga needle was used. Paper-wrapping of biopsies did not improve quality. CONCLUSIONS: In small dogs, collection of humeral BM biopsies using a 15g needle is feasible and more easily accomplished than collection using a 13ga needle. Hematopoiesis may be underestimated in specimens collected using the smaller needle.

Independent and combined effects of prednisone and acetylsalicylic acid on thromboelastography variables in healthy dogs.

OBJECTIVE: To describe the effects of prednisone and acetylsalicylic acid (ASA) on results of thromboelastography in healthy dogs. ANIMALS: 16 male mixed-breed dogs. PROCEDURES: Dogs were randomly assigned to 3 treatment groups (4 dogs/group) that received prednisone (median dose, 2.07 mg/kg), ASA (median dose, 0.51 mg/kg), or both drugs, PO, every 24 hours from days 0 through 6. Another group received no treatment (control dogs; n = 4). Thromboelastography variables (reaction time, clotting time, α-angle, maximum amplitude [MA], global clot strength, coagulation index, and percentage of clot lysis at 60 minutes [CL(60)]) were evaluated in blood samples collected (prior to drug administration in treated dogs) on days 0 (baseline), 2, 4, and 6. RESULTS: Administration of ASA alone did not alter TEG variables. For treatment effect, mean global clot strength was increased in the prednisone and drug combination groups, compared with values for control dogs; MA was also increased in the prednisone and drug combination groups, compared with that of controls. For treatment-by-time effect, median CL(60) was increased in the prednisone group on day 6, compared with baseline value in the same dogs and with median CL(60) of the control group on day 6. Median CL(60) was also increased in the drug combination group on day 6, compared with the baseline value and with that of the control group on day 6. CONCLUSIONS AND CLINICAL RELEVANCE: Prednisone administered at approximately 2 mg/kg/d, PO, for 7 days with or without concurrently administered ASA increased clot strength and decreased clot lysis in healthy dogs.

The use of vascular access ports for blood collection in feline blood donors.

We investigated vascular access ports for feline blood donation. Eight cats were anesthetized for conventional blood collection by jugular venipuncture at the beginning and end of the study. In-between conventional collections, vascular access ports were used for collection with or without sedation every 6 to 8 wk for 6 mo. Ports remained functional except for one catheter breakage, but intermittent occlusions occurred. Systolic blood pressure was lower during conventional collection. Behavioral abnormalities occurred during 3 port collections. Packed red cells prepared from collected blood were stored at 4°C for 25 d and assessed for quality pre- and post-storage. With both collection methods, pH and glucose level declined, and potassium level, lactate dehydrogenase activity and osmotic fragility increased. There were no differences between methods in pre-storage albumin and HCO(3)(-) levels, and pre and post-storage hematocrit, lactate dehydrogenase activity, and glucose and potassium levels. Pre-storage pH and pCO(2) were higher with conventional collection, and pre- and post-storage osmotic fragility were greater with port collection. One port became infected, but all cultures of packed red cells were negative. Tissue inflammation was evident at port removal. In a second study of conventional collection in 6 cats, use of acepromazine in premedication did not exacerbate hypotension. The use of vascular access ports for feline blood donation is feasible, is associated with less hypotension, and may simplify donation, but red cell quality may decrease, and effects on donors must be considered.

The use of lithium carbonate to prevent lomustine-induced myelosuppression in dogs: a pilot study.

This was a preliminary investigation of the use of lithium to prevent lomustine-induced myelosuppression. Four 10 to 11 kg beagles received lomustine 20 to 30 mg, PO, q3wk, with cephalexin prophylaxis. Two dogs also received lithium, 150 to 300 mg, PO, q12h. Lithium blood concentrations fluctuated in and out of therapeutic interval. Lithium was discontinued in one dog in week 13, and in the other dog in week 38, due to toxicoses. All dogs developed grade 1 to 4 neutropenia after each lomustine treatment. In dogs receiving lomustine only, platelet concentrations decreased from 274 and 293 × 10(9)/L in week 1, to 178 and 218 × 10(9)/L in weeks 38 and 13, respectively. In dogs receiving lomustine and lithium, platelet concentrations decreased from 351 and 288 × 10(9)/L in week 1, to 214 and 212 × 10(9)/L, in weeks 36 and 13, respectively. Lithium did not prevent lomustine-induced myelosuppression and had important side-effects.