Melissa Claus

Objectives: To compare the hemostatic characteristics of cold-stored whole blood (CSWB) from non-greyhound dogs (NGD) and greyhound dogs (GD) over 42 days of storage, notably, platelet closure time (PCT) (NGD only), manual platelet count (PLT) (GD only), ellagic acid (INTEM) and tissue factor activated (EXTEM) rotational thromboelastometry, prothrombin (PT) and activated partial thromboplastin time (aPTT), fibrinogen concentration (FIB), and the activities of factors (F) FII, FV, FVII, FVIII, FIX, FX, FXIII antigen (FXIII:Ag), and von Willebrand factor antigen (vWF:Ag).

Design: Whole blood from 10 NGD and 10 GD, was refrigerated in CPD blood bags at 4 degrees C for 42 days. Blood was analyzed before refrigeration (day 0) and at day 1 (d1), 3, 5, 7, 10, 14, 17, 21, 24, 28, 31, 35, 38, and 42. Multivariate linear mixed effects models were created to evaluate coagulation parameters over time and compare NGD and GD. Data are summarized as estimated marginal means with 95% confidence intervals. Significance was set at P < 0.05.

Results: The PCT for all NGD CSWB was above the device limit by d7. The PLT for GD CSWB did not change during storage. The mean alpha-angle for INTEM and EXTEM decreased to < 50% of baseline at d38 and d31 for NGD, and d31 and d17 for GD CSWB. The mean maximum clot firmness (MCF) for INTEM and EXTEM reduced to < 50% of baseline at d42 and d28 for both GD and NGD. PT and aPTT for NGD and GD increased over time. For NGD CSWB, the mean FVIII and vWF:Ag activities decreased to < 50% of baseline at d7 and d28, respectively, and FIB reached 0.982 g/dL by d24. For GD CSWB, FVIII, FXIII:Ag and FV activities decreased to < 50% of baseline by d3, d38, and d38, respectively, and FIB was 0.982 g/dL at baseline. Alpha-angle and MCF for both INTEM and EXTEM, and activities for FII, FV, FIX, FXIII:Ag were significantly lower, and vWF:Ag was significantly higher overall in GD CSWB compared with NGD. A significant difference in the pattern of change over time was detected between NGD and GD in EXTEM alpha-angle, INTEM and EXTEM MCF, FII, and FVIII activities.

Conclusions: The in vitro viscoelastic parameters of GD and NGD CSWB declines over 42 days, but numerous hemostatic parameters (INTEM and EXTEM alpha-angle and MCF, activity of FII, FV, FV, FVII, FIX, FX, FXIII:Ag, vWF:Ag, and FIB) remain within 50% of baseline for more than 14 days. CSWB from GD compared to NGD has reduced hemostatic activity overall, but a similar pattern of decline for most parameters over time.

Red blood cell (RBC) transfusion is associated with recipient inflammation and infection, which may be triggered by excessive circulating iron. Iron chelation following transfusion may reduce these risks. The aim of this study was to evaluate the effect of deferoxamine on circulating iron and inflammation biomarkers over time and in vitro growth of Escherichia coli (E. coli) following RBC transfusion in dogs with atraumatic hemorrhage. Anesthetized dogs were subject to atraumatic hemorrhage and transfusion of RBCs, then randomized to receive either deferoxamine or saline placebo of equivalent volume (n = 10 per group) in a blinded fashion. Blood was sampled before hemorrhage and then 2, 4, and 6 h later. Following hemorrhage and RBC transfusion, free iron increased in all dogs over time (both p < 0.001). Inflammation biomarkers interleukin-6 (IL6), CXC motif chemokine-8 (CXCL8), interleukin-10 (IL10), and keratinocyte-derived chemokine (KC) increased in all dogs over time (all p < 0.001). Logarithmic growth of E. coli clones within blood collected 6 h post-transfusion was not different between groups. Only total iron-binding capacity was different between groups over time, being significantly increased in the deferoxamine group at 2 and 4 h post-transfusion (both p < 0.001). In summary, while free iron and inflammation biomarkers increased post-RBC transfusion, deferoxamine administration did not impact circulating free iron, inflammation biomarkers, or in vitro growth of E. coli when compared with placebo.

Objectives: To compare concentrations of biomarkers of; allergy [mast cell tryptase (MCT) and histamine], inflammation [interleukin (IL)-6,-10, and−18, CXCL8, CCL2, keratinocyte chemoattractant (KC), C-reactive protein (CRP)], endothelial glycocalyx shedding (hyaluronan), coagulation [prothrombin time, activated partial thromboplastin time, fibrinogen concentration, and von Willebrand Factor antigen, protein C (PC) and antithrombin (AT) activity], and hepatopathy [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin] between dogs with anaphylaxis after suspected insect exposure, dogs with critical illness, and healthy dogs. Design: This was a single center prospective clinical observational comparative biomarker study that included 25 dogs with anaphylaxis (evidence of insect exposure, acute dermatological signs, and other organ involvement), 30 dogs with other critical illness, and 20 healthy dogs. Differences across groups in biomarker concentrations were tested using one-way ANOVA or Kruskal-Wallis test, with significant P values (<0.05) reported for pairwise differences detected by post-hoc tests. Logistic regression models were used to calculate the area under the receiver operator characteristic curve (AUROC) for discrimination between anaphylaxis and non-anaphylactic illness. Results: Histamine concentration was significantly higher in the anaphylaxis group than the healthy (P < 0.001) and critically ill groups (P < 0.001), whereas no differences in MCT were detected amongst groups. Biomarker concentrations that were increased relative to healthy dogs in both the anaphylaxis and critically ill groups included IL-10 (P < 0.001 and P = 0.007, respectively), CCL2 (P = 0.007 and P < 0.001, respectively) and AST (both P < 0.001), whereas only the critically ill group had significantly increased CRP (P < 0.001), IL-6 (P < 0.001), KC (P < 0.001), ALP (P < 0.001), and fibrinogen (P = 0.016) concentrations, compared to the healthy group. Only dogs with anaphylaxis had significantly higher hyaluronan (P = 0.021) and ALT (P = 0.021) concentrations, and lower PC (P = 0.030) and AT (P = 0.032) activities, compared to healthy dogs. Both CRP and histamine concentration showed good discrimination between anaphylaxis and other critical illness, with an AUROC of 0.96 (95% CI 0.91–1) and 0.81 (95% CI 0.69–0.93), respectively. Conclusions: This preliminary study in dogs with anaphylaxis after suspected insect exposure, found evidence of an early innate immune response, glycocalyx shedding and anticoagulant consumption. Both CRP and histamine showed potential clinical utility for differentiation between anaphylaxis and other critical illness.

Background Prestorage leukoreduction of red blood cell (RBC) bags prevents accumulation of pro-inflammatory mediators and experimentally attenuates post-transfusion inflammation in healthy dogs. However, the effect of leukoreduction on post-transfusion inflammation in critically ill dogs is unclear. Hypothesis Dogs transfused with leukoreduced (LR) RBC will have lower concentrations of leukocytes, interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and C-reactive protein (CRP) within 24 hours of post-transfusion compared to dogs transfused with nonleukoreduced (NLR) RBC. Animals Sixty-one RBC-transfused dogs (LR = 34, NLR = 27). Methods Randomized, blinded, controlled preliminary clinical trial. Blood bag processing was randomized to create identically appearing LR and NLR bags. Group allocation occurred with transfusion of the oldest compatible RBC bag. Blood samples were collected pretransfusion and at 8 and 24 hours post-transfusion for leukocyte count, IL-6, IL-8, MCP-1, and CRP. Data were analyzed on an intention-to-treat basis using linear mixed effects models. Significance was set at P < .05. Results No significant differences were found between groups in concentrations of leukocytes (P = .93), IL-6 (P = .99), IL-8 (P = .75), MCP-1 (P = .69), or CRP (P = .18) over time. Eleven LR dogs (32%) and 4 NLR dogs (15%) were euthanized in the hospital (P = .14). No natural deaths occurred. Conclusions and Clinical Importance No differences in inflammation biomarker concentrations were detected over time between dogs transfused with LR or NLR RBC, but heterogeneity likely hampered the ability to detect a difference with this sample size. The novel randomization and enrollment protocol was successfully implemented across 2 participating institutions and will be easily scaled up for a future multicenter clinical trial.

Synthetic colloid fluids containing hydroxyethyl starch (HES) have been associated with impairment of coagulation in dogs. It is unknown if HES causes coagulation impairment in dogs with naturally occurring critical illness. This study used banked plasma samples from a blinded, randomized clinical trial comparing HES and balanced isotonic crystalloid for bolus fluid therapy in 39 critically ill dogs. Blood was collected prior to fluid administration and 6, 12, and 24 h thereafter. Coagulation biomarkers measured at each time point included prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen concentration, and the activities of coagulation factors V, VII, VIII, IX, and X, von Willebrand factor antigen, antithrombin, and protein C. Given the links between coagulation and inflammation, cytokine concentrations were also measured, including interleukins 6, 8, 10, and 18, keratinocyte-derived chemokine, and monocyte chemoattractant protein-1. Data were analyzed with linear mixed effects models. No significant treatment-by-time interactions were found for any biomarker, indicating that the pattern of change over time was not modified by treatment. Examining the main effect of time showed significant changes in several coagulation biomarkers and keratinocyte-derived chemokines. This study could not detect evidence of coagulation impairment with HES.

Objective The primary objective of this study was to document coagulation factor activity in canine “NEVER-FROZEN” and “THAWED” refrigerated plasma for the purposes of defining recommended expiration dates. We hypothesized that NEVER-FROZEN and THAWED refrigerated plasma would maintain >50% activity of coagulation factors V (FV), VII (FVII), VIII (FVIII), IX (FIX), X (FX), and von Willebrand factor antigen (vWF) and a concentration of fibrinogen above the lower bound of the reference interval (>0.982 g/L) for greater than 14 days but less than 42 days. Design Prospective laboratory-based study. Setting University teaching hospital blood bank. Animals Ten canine plasma units derived from healthy client-owned blood donors. Interventions Serial sampling (days 0, 1, 3, 5, 7, 10, 14, 17, 21, 24, 28, 32, 35, 39, 42) from NEVER-FROZEN and THAWED refrigerated canine plasma units was conducted for measurement of activities of FV, FVII, FVIII, FIX, FX, vWF, and fibrinogen concentrations using the ACL TOP 300. Plasma was defined as “suitable for transfusion” at a given time point if the entire 95% confidence interval for each factor was above 50% activity and above a fibrinogen concentration of 0.982 g/L. Measurements and main results The lower bounds of the FVIII and vWF confidence intervals were above 50% up to and including day 32 for NEVER-FROZEN refrigerated plasma and day 28 for THAWED refrigerated plasma. Confidence intervals for FV, FVII, FIX, and FX remained above 50% activity at all time points. The lower bound of the fibrinogen concentration was <0.982 g/L on day 39 for NEVER-FROZEN refrigerated plasma and on day 35 for THAWED refrigerated plasma. Conclusions Refrigerated canine plasma from these 10 dogs retained coagulation factor activity above the limit that we defined as suitable for transfusion for up to 32 days when NEVER-FROZEN and 28 days when THAWED. Further studies should evaluate the clinical outcomes and effects on coagulation factor activity of dogs receiving refrigerated plasma transfusions.

Objective: To evaluate the effect of 6% hydroxyethyl starch (HES) 130/0.4, compared with a Hartmann's solution control (CRYST), on urine biomarkers of acute kidney injury (AKI) in dogs prescribed a fluid bolus. Design: Randomized, controlled, blinded clinical trial January 2018 to February 2019. Setting: University teaching hospital. Animals: Forty client‐owned dogs. Interventions: Dogs prescribed a fluid bolus were randomized to receive at least 10 mL/kg of HES or CRYST with clinicians and investigators blinded to fluid type. Study fluid was used for further boluses as required in the following 24 hours, to a limit of 40 mL/kg total, after which fluid administration was open‐label. Measurements and Main Results: Urine was collected prior to and 6, 12, and 24 hours after the first study fluid bolus. Urine concentrations of AKI biomarkers: neutrophil gelatinase‐associated lipocalin (NGAL), cystatin C, kidney injury molecule‐1 (KIM), clusterin, and osteopontin were measured using a magnetic bead multiplexed assay. Osmolality‐indexed biomarker concentrations were compared between groups over time with linear mixed‐effects models, with P < 0.05 considered significant. The mean volume of study fluid administered was not significantly different between groups (HES: 23.1 mL/kg, CRYST: 25.9 mL/kg; P = 0.47, t‐test). There were no significant differences between groups in change over time of osmolality‐indexed urine concentrations of NGAL (P = 0.91), cystatin C (P = 0.95), KIM (P = 0.77), clusterin (P = 0.63), or osteopontin (P = 0.91). The maximum Veterinary Acute Kidney Injury (VAKI) score up to 7 days during hospitalization (P = 1.0) and in‐hospital mortality (P = 0.49) were not significantly different between groups, as compared by Fisher's exact test. Conclusions: There were no differences in change over time of urine AKI biomarkers in dogs treated with 10 – 40 mL/kg HES or CRYST over 24 hours. Larger clinical trials with patient‐centered outcomes are required to investigate the safety of HES in dogs.

Objective To describe small animal transfusion practices in Australia, including access to blood products and frequency of pre‐transfusion compatibility testing and medication administration. Methods An online survey was disseminated to target Australian veterinarians treating dogs and cats. Information collected included demographics, sources of blood products, blood storage, recipient compatibility testing and administration of medications pre‐transfusion. Associations between the use of compatibility tests and premedications were assessed using the χ2 test. Significance was set at P < 0.05. Results A total of 199 Australian veterinarians were included; however, there was some attrition of respondents over the course of the survey. The majority of respondents were in general practice (n = 133/199). Access to fresh whole blood was commonly reported for dogs (n = 179/199) and cats (n = 131/198), whereas blood components were less commonly available (canine red blood cells [RBC], n = 52/199 and plasma, n = 157/199; feline RBC, n = 9/198 and plasma, n = 21/198). Most blood was sourced from the pets of owners affiliated with the veterinary clinic (n = 179/196). The respondents who did not blood type or crossmatch dogs were significantly more likely to use premedication than those who did these tests (both comparisons: P < 0.001). Likewise, the respondents who did not blood‐type cats were significantly more likely to use premedication (P = 0.003); however, there was no association between crossmatching and using premedication in cats (P = 0.183). Conclusion This is the first survey to describe transfusion practices across a variety of practice types throughout Australia. Future work is needed to determine how representative these results are of current transfusion practices across Australia, and if so, what can be done to optimise them.