Modern veterinary blood banking practices and their applications in companion animal practice

In vitro compatibility testing of canine and rabbit blood

OBJECTIVE

To determine the in vitro compatibility of rabbit and canine blood using both a tube and slide agglutination crossmatch technique and to compare the results obtained from these 2 methods.

DESIGN

Prospective observational laboratory study from January to March 2020.

SETTING

University veterinary teaching hospital.

ANIMALS

Six client-owned rabbits ≥3.5 kg undergoing phlebotomy for a clinical reason. "Pigtail" blood samples from 3 dog erythrocyte antigen (DEA) 1-positive and 3 DEA 1-negative canine packed red blood cell units.

INTERVENTIONS

Blood from each rabbit was crossmatched with a single unit of canine blood using both a standard laboratory tube agglutination technique and a simple slide agglutination method with each rabbit/canine unit serving as its own intraassay control. Tube crossmatches were evaluated for agglutination both macro- and microscopically and assessed for hemolysis. Slide crossmatches were assessed for the presence of agglutination both macro- and microscopically.  MEASUREMENTS AND MAIN RESULTS: All crossmatches were incompatible. Varying degrees of agglutination were seen for all crossmatches. Hemolysis was observed with all minor tube crossmatches. Results of both crossmatch techniques were in close agreement.  CONCLUSIONS: The crossmatch results in this present study strongly demonstrate in vitro incompatibility between canine and rabbit blood. Agreement between the 2 techniques in this study indicates that the slide agglutination technique may be quicker, require less blood, and provide reliable results in exclusively assessing the compatibility of canine and rabbit blood. Based on the results of this study, emergency xenotransfusion of canine blood to rabbits cannot be recommended.

Red Blood Cell Cryopreservation with Minimal Post-Thaw Lysis Enabled by a Synergistic Combination of a Cryoprotecting Polyampholyte with DMSO/Trehalose

From trauma wards to chemotherapy, red blood cells are essential in modern medicine. Current methods to bank red blood cells typically use glycerol (40 wt %) as a cryoprotective agent. Although highly effective, the deglycerolization process, post-thaw, is time-consuming and results in some loss of red blood cells during the washing procedures. Here, we demonstrate that a polyampholyte, a macromolecular cryoprotectant, synergistically enhances ovine red blood cell cryopreservation in a mixed cryoprotectant system. Screening of DMSO and trehalose mixtures identified optimized conditions, where cytotoxicity was minimized but cryoprotective benefit maximized. Supplementation with polyampholyte allowed 97% post-thaw recovery (3% hemolysis), even under extremely challenging slow-freezing and -thawing conditions. Post-thaw washing of the cryoprotectants was tolerated by the cells, which is crucial for any application, and the optimized mixture could be applied directly to cells, causing no hemolysis after 1 h of exposure. The procedure was also scaled to use blood bags, showing utility on a scale relevant for application. Flow cytometry and adenosine triphosphate assays confirmed the integrity of the blood cells post-thaw. Microscopy confirmed intact red blood cells were recovered but with some shrinkage, suggesting that optimization of post-thaw washing could further improve this method. These results show that macromolecular cryoprotectants can provide synergistic benefit, alongside small molecule cryoprotectants, for the storage of essential cell types, as well as potential practical benefits in terms of processing/handling.

Transfusion practice in Australia: an internet-based survey

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.

Ex vivo evaluation of the efficacy of canine fresh-frozen plasma thawed using a microwave plasma defroster

BACKGROUND

Commercial microwave plasma defrosters (MPDs) are used globally in human medicine to safely thaw fresh-frozen plasma (FFP), but this technology has never been tested in a veterinary setting. This study was undertaken to assess the efficacy of a commercial MPD for the rapid thawing of canine FFP.

STUDY DESIGN

Twenty-three units (twelve 120 mL and eleven 240 mL) of canine FFP were thawed using an MPD. Time-to-thaw and pre- and postthawing temperatures of the units were measured. Clotting factor activities (factors II, V, VII, VIII, IX, X, and von Willebrand factor), fibrinogen concentrations, prothrombin times, and activated partial thromboplastin times were measured.

KEY FINDINGS

The evaluated MPD effectively thaws plasma quickly for both 120 mL units (2.7 ± 0.08 min) and 240 mL units (3.9 ± 0.15 min) while maintaining clinically relevant activities of clotting factors and fibrinogen concentration. While some measurements of factor VIII activity fell below the reference interval, none fell below 40%. One 240 mL unit had von Willebrand factor activity <70%. There was no evidence of excessively heated plasma to indicate a safety concern.

SIGNIFICANCE

The MPD evaluated in this study provides a useful means to rapidly thaw canine FFP for correction of factor-deficient coagulopathy.

Prevalence of Dog Erythrocyte Antigen 1 in 7,414 Dogs in Italy

The study aim was to establish the prevalence of DEA 1, the most immunogenic and clinically important blood group in canine blood transfusion, in 7,414 dogs from Italy. The potential sensitization risk following a first transfusion and the acute reaction risk following a second transfusion given without a cross-matching and blood typing test were also calculated. Dogs tested were purebred (4,798) and mongrel (2,616); 38.8% were DEA 1 negative and 61.2% were DEA 1 positive. High prevalence for DEA 1 positive blood type was found in Ariegeois and English Setter, whereas German Shepherd and Boxer had higher DEA 1 negative blood type. Breeds with blood type never reported before included French Brittany Spaniel and Pug showing a high prevalence of DEA 1 positive type, while French Bulldog and West Highland White Terrier were more often DEA 1 negative. Just 48.8% of purebred and 13.9% of mongrel dogs were considered as prospective blood donors based upon their blood type. Most of the breeds had a sensitization risk of 20.0–25.0%. Rottweiler and Ariegeois had less risk of sensitization (9.4 and 4.2%) and the minor risk of an acute transfusional reaction (0.9–0.2%). The prevalence of DEA 1 positive and negative dogs in Italy agrees with most of the data already reported in the literature.

Exploring the Possibility of Cryopreservation of Feline and Canine Erythrocytes by Rapid Freezing with Penetrating and Non-Penetrating Cryoprotectants

Efficient application of veterinary blood transfusion approaches for small companion animals requires readily available supply of the donor material. This can be achieved by developing of effective biobanking technologies allowing long-term storage of donor blood components via cryopreservation. Transfusion of an erythrocyte concentrate allows the successful correction of various hematological pathologies, severe bleeding, and etc. While in the past there were several approaches to cryopreserve red blood cells of dogs, to our knowledge there is virtually no data on cryopreservation of feline erythrocytes. In this paper, we performed a comprehensive parameter optimization for low temperature storage of RBCs of both species. Here, the efficiency of single-component and multicomponent cryoprotective media as well as necessary time of pre-incubation with penetrating and non-penetrating cryoprotectants prior to rapid freezing is analyzed. This study showed that glycerol was not sufficient for cryopreservation of red blood cells of the studied species under the investigated conditions. Application of 10% (v/v) ME2SO allowed for a significant reduction of canine and feline erythrocytes hemolysis after thawing. 17.5% hydroxyethyl starch demonstrated the highest cryoprotective activity for both species. It was found that dog RBCs should be incubated in cryoprotective media for 30 min at 22°C prior to freezing, while for cat RBCs 20 min is sufficient. Combination of CPAs was less effective. Presented data may be considered in further studies in veterinary transfusion and blood banking optimization.

A successful transfusion in a tamandua (Tamandua tetradactyla) using both whole blood and blood replacement products

A 10-yr-old tamandua (Tamandua tetradactyla) presented with severe lethargy and ataxia. Severe anemia (9% hematocrit) was diagnosed and ultimately resolved with the administration of a whole blood transfusion from conspecific and additional blood replacement products (Oxyglobin). This is the first described use of a whole blood transfusion in an edentate.

Description and evaluation of a canine volunteer blood donor program

Human volunteer blood donor programs are commonplace, but the concept of nonhuman animal blood banking is relatively new. Few studies exist regarding efficacy, donor screening, and safety for volunteer companion animals. This retrospective study evaluated a nonprofit, community-based canine volunteer donor program using community blood drives. Of 98 potential donors, 14 were ineligible to donate, including 4 who tested seropositive for blood-borne pathogens. Of 84 donors, 45 were Dog Erythrocyte Antigen (DEA) 1.1 positive and 39 were DEA1.1 negative. Donations totaling 143 included 29 repeat donors (35%). No serious adverse events occurred. Minor adverse events included acute donor reaction (2.8%), hematoma (4.2%), rebleeding (2.1%), and skin irritation (0.7%). Adverse event rates were comparable to data for human blood donations. A substantial fraction of donors donated multiple times, suggesting that volunteer donors and their guardians perceived the donation process to be safe and effective. This article discusses the issue of donor consent and use of the term volunteer. This study indicates that nonprofit, community-based canine volunteer donor programs for animal blood banks can be successful while maintaining high safety standards and ethical treatment of volunteers.

Comparison of 4 blood storage methods in a protocol for equine pre-operative autologous donation

OBJECTIVE

To compare viability of equine whole blood stored by 4 different methods, and to establish optimal storage protocols for an equine autologous blood donation program.

STUDY DESIGN

In vitro study of stored equine whole blood. Animals- Six healthy adult horses.

METHODS

Blood from each horse was collected into 4 different containers: glass bottles containing acid-citrate-dextrose solution (ACD), plastic bags containing ACD, citrate-phosphate-dextrose (CPD), and CPD with supplemental adenine (CPDA-1). Blood was stored for 5 weeks and sampled at 2-day intervals. Standard hematologic and biochemical variables were evaluated, and adenosine-5-triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG) concentrations were measured and normalized to total hemoglobin content.

RESULTS

Plasma hemoglobin, % hemolysis, lactate, potassium, ammonia, and lactate dehydrogenase (LDH) increased, whereas glucose concentration and pH decreased in all stored blood over 5 weeks. There was a temporal increase in hemolysis with all storage methods, but the increase was greatest in glass bottles. Lactate and ammonia were highest in CPD and CPDA-1 samples, indicating more active red blood cell (RBC) metabolism. 2,3-DPG concentrations decreased during storage, but were optimally preserved with CPDA-1. ATP concentrations were significantly higher for blood stored in CPDA-1, and were lowest in glass bottles.

CONCLUSIONS

Hematologic and biochemical values measured for blood stored in CPDA-1 are suggestive of improved RBC viability compared with other storage methods. With the exception of ATP, results from stored equine blood were similar to those reported for other species.

CLINICAL RELEVANCE

Commercial CPDA-1 bags appear to be the optimal storage method for equine whole blood.

Aggregability and post-transfusion survival of canine platelets in stored whole blood

The effects of whole blood storage time on platelet aggregation and on post-transfusion platelet survival time were assessed in dogs. Citrate phosphate dextrose adenine-1 (CPDA-1) was used as a blood cell preservative. Storage time dependent decay of platelet aggregability was assessed. Platelet aggregation responses to collagen and ADP were maintained for at least 8 hr at room temperature. During blood storage, immunoglobulin became nonspecifically bound to platelets, suggesting the potential for immune destruction of platelets by the mononuclear phagocyte system after transfusion. To assess this assumption, the survival times of infused platelets, which were stored for 0 to 8 hr in whole blood, were measured. Post-transfusion survival of platelets was not affected by these storage times. These results suggest that canine platelets maintain viability when stored at room temperature for up to 8 hr in CPDA-1 treated whole blood intended for transfusion.