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- Author or Editor: John M. Thomason x
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Abstract
OBJECTIVE
To evaluate coagulation factors in units of leukoreduced (LR) and nonleukoreduced (non-LR) canine fresh-frozen plasma (cFFP).
ANIMALS
8 healthy research dogs.
PROCEDURES
In a crossover study, dogs were randomly assigned to 1 of 2 groups from which blood was collected and either did or did not undergo leukoreduction. After a recovery period of ≥ 28 days, the dogs were switched between protocols. After each collection, blood samples were centrifuged, and cFFP was stored frozen for later comparative analysis of coagulation factors, antithrombin, and protein C activities (reported as comparative percentages of the corresponding activities determined in a canine pooled plasma standard); prothrombin and activated partial thromboplastin times; and fibrinogen concentration.
RESULTS
There were no significant differences detected between results for LR cFFP, compared with those for non-LR cFFP.
CONCLUSIONS AND CLINICAL RELEVANCE
Although there was variation among residual activities of coagulation factors in LR and non-LR cFFP, the variations and differences were considered unlikely to impact the efficacy of LR cFFP transfused for coagulation factor replacement in dogs. However, owing to the small sample size and high variability of results in the present study, additional research with a larger sample size is required for definitive conclusions on the effects of leukoreduction on coagulation factors in cFFP and to develop treatment guidelines for LR cFFP use in dogs with congenital and acquired coagulopathies.
Abstract
OBJECTIVE To assess the in vitro and in vivo platelet function of healthy dogs during administration of a low-dose aspirin regimen.
ANIMALS 16 dogs.
PROCEDURES Dogs received aspirin (1 mg/kg, PO, q 24 h) for 7 days. Blood and urine samples were collected before (day 1; baseline) and on days 3 and 7 of the low-dose aspirin regimen. Platelet function was evaluated by use of turbidimetric and conventional impedance aggregometry, multiple-electrode impedance aggregometry, a platelet function analyzer (PFA), and determination of urine 11-dehydro-thromboxane B2 concentration. Turbidimetric aggregometry results were compared with the results obtained by the other 4 methods. Fourteen days after cessation of aspirin, platelet-rich plasma was incubated with acetylsalicylic acid and platelet function was assessed by turbidimetric aggregometry to determine whether this technique could accurately identify dogs that responded to the low-dose aspirin regimen.
RESULTS Of the 16 dogs, 13 had turbidimetric and conventional impedance aggregometry results that were decreased by > 25% from baseline on days 3 and 7, and 4 and 7 dogs had PFA closure times > 300 seconds on days 3 and 7, respectively. The median urine 11-dehydro-thromboxane B2 concentration–to–creatinine concentration ratio decreased by 49% between days 1 and 7. Turbidimetric aggregometry results were correlated with conventional impedance aggregometry results. There was poor agreement between the turbidimetric aggregometry and PFA results. The multiple-electrode impedance aggregometry protocol failed to reliably detect aspirin-induced platelet dysfunction. In vitro incubation of platelet-rich plasma with acetylsalicylic acid followed by turbidimetric aggregometry did not predict whether dogs responded to the low-dose aspirin regimen.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the response to a low-dose aspirin regimen varied among healthy dogs. (Am J Vet Res 2016;77:174–185)
Abstract
OBJECTIVE To evaluate eicosanoid concentrations in freshly prepared canine packed RBCs (PRBCs) and to assess changes in eicosanoid concentrations in PRBC units over time during storage and under transfusion conditions.
DESIGN Prospective study.
SAMPLE 25 plasma samples from 14 healthy Greyhounds.
PROCEDURES Plasma samples were obtained during PRBC preparation (donation samples), and the PRBC units were then stored at 4°C until used for transfusion (≤ 21 days later; n = 17) or mock transfusion if expired (22 to 24 days later; 8). Immediately prior to use, 100 mL of saline (0.9% NaCl) solution was added to each unit and a pretransfusion sample was collected. A posttransfusion sample was collected after transfusion or mock transfusion. Concentrations of arachidonic acid, prostaglandin (PG) F2α, PGE2, PGD2, thromboxane B2, 6-keto-PGF1α, and leukotriene B4 were measured by liquid chromatography–mass spectrometry and analyzed statistically.
RESULTS Median arachidonic acid concentration was significantly decreased in posttransfusion samples, compared with the concentration in donation samples. Median PGF2α, 6-keto-PGF1α, and leukotriene B4 concentrations were significantly increased in pretransfusion samples, compared with those in donation samples. Median PGF2α, thromboxane B2, and 6-keto-PGF1α concentrations were significantly increased in posttransfusion samples, compared with those in pretransfusion samples. Duration of PRBC storage had significant associations with pretransfusion and posttransfusion arachidonic acid and thromboxane B2 concentrations.
CONCLUSIONS AND CLINICAL RELEVANCE Concentrations of several proinflammatory eicosanoids increased in PRBC units during storage, transfusion, or both. Accumulation of these products could potentially contribute to adverse transfusion reactions, and investigation of the potential association between eicosanoid concentrations in PRBCs and the incidence of transfusion reactions in dogs is warranted.
Abstract
OBJECTIVE
To determine the effects of leukoreduction on N-methylhistamine (NMH; a stable histamine metabolite) concentration in units of canine whole blood during storage and incubation at room temperature (approx 22 °C) to simulate temperature conditions during transfusion.
ANIMALS
8 healthy adult Walker Hounds.
PROCEDURES
A standard unit of blood (450 mL) was obtained from each dog twice, with at least 28 days between donations. Blood units collected from 4 dogs during the first donation underwent leukoreduction, whereas the blood units collected from the other 4 dogs did not undergo leukoreduction, prior to storage at 4 °C. The alternate treatment was applied to blood units collected during the second donation. A sample from each unit was obtained for determination of plasma NMH concentration the day of donation (before and after leukoreduction when applicable) and before and after incubation at room temperature for 5 hours on days 14 and 28 of storage.
RESULTS
Units that underwent leukoreduction had substantially lower leukocyte and platelet counts than nonleukoreduced units. Plasma NMH concentration increased immediately after leukoreduction but did not change significantly during the subsequent 28 days of storage, nor did it differ between units that did and did not undergo leukoreduction.
CONCLUSIONS AND CLINICAL RELEVANCE
Leukoreduction and simulated transfusion temperature did not affect the histamine load in units of canine whole blood during the first 28 days of storage. Further research is necessary to determine whether histamine contributes to the development and severity of blood transfusion reactions in dogs.
Abstract
OBJECTIVE
To determine whether passage of whole blood through a microaggregate filter by use of a syringe pump would damage canine erythrocytes.
SAMPLE
Blood samples obtained from 8 healthy client-owned dogs.
PROCEDURES
Whole blood was passed through a standard microaggregate filter by use of a syringe pump at 3 standard administration rates (12.5, 25, and 50 mL/h). Prefilter and postfilter blood samples were collected at the beginning and end of a simulated transfusion. Variables measured at each time point included erythrocyte osmotic fragility, mean corpuscular fragility, RBC count, hemoglobin concentration, RBC distribution width, and RBC morphology. In-line pressure when blood passed through the microaggregate filter was measured continuously throughout the simulated transfusion. After the simulated transfusion was completed, filters were visually analyzed by use of scanning electron microscopy.
RESULTS
Regardless of administration rate, there was no significant difference in mean corpuscular fragility, RBC count, hemoglobin concentration, or RBC distribution width between prefilter and postfilter samples. Additionally, there were no differences in in-line pressure during the simulated transfusion among administration rates. Echinocytes were the erythrocyte morphological abnormality most commonly observed at the end of the transfusion at administration rates of 12.5 and 25 mL/h.
CONCLUSIONS AND CLINICAL RELEVANCE
Results suggested that regardless of the administration rate, the microaggregate filter did not alter fragility of canine RBCs, but may have altered the morphology. It appeared that the microaggregate filter would not contribute to substantial RBC damage for transfusions performed with a syringe pump.
