Retrospective evaluation of the prevalence and risk factors associated with red blood cell transfusions in cats with urethral obstruction (2009-2019): 575 cases.

OBJECTIVE: To evaluate the prevalence of red blood cell (RBC) transfusions and factors associated with the need for transfusion in cases of feline urethral obstruction (FUO). Secondarily, to compare survival to discharge in cats receiving an RBC transfusion versus those that did not. DESIGN: Retrospective, multi-institutional study from 2009 to 2019. SETTING: Four university teaching hospitals. ANIMALS: Six hundred twenty-two total occurrences of FUO in 575 cats. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records were retrospectively reviewed for pertinent information. The overall prevalence of severe anemia (PCV < 0.20 L/L [<20%]) at presentation was 1.0% (6/622). The prevalence of RBC transfusions during hospitalization was 2.1% (13/622). Cats that received an RBC transfusion weighed significantly less than those that did not (4.9 vs 5.8 kg; P = 0.034) and had a lower PCV at presentation (0.30 L/L [30%] vs 0.41 L/L [41%]; P < 0.001). Hospitalization time (240 vs 72 h) and indwelling urinary catheter time (168 vs 48 h) were significantly longer in cats receiving a transfusion compared with those that did not (P < 0.001). Creatinine concentrations were not significantly associated with transfusion administration, while BUN was higher in cats receiving a transfusion (15.35 mmol/L [43 mg/dL] vs. 11.78 mmol/L [33 mg/dL]; P = 0.043). Transfusion rates were significantly higher in cats undergoing perineal urethrostomy (5.5%) compared with those that did not undergo surgery (0.97%; P < 0.001). The overall survival to discharge rate was 96%. Cats not receiving an RBC transfusion were significantly more likely to survive to discharge than those that did (odds ratio: 14.7, 95% confidence interval: 1.8-37; P < 0.001). CONCLUSIONS: FUO is rarely associated with severe anemia and the need for RBC transfusions. In this study, cats receiving an RBC transfusion were less likely to survive to discharge; therefore, requiring a blood transfusion may be associated with a worse prognosis. In addition, the need for surgical intervention was associated with a higher prevalence of RBC transfusions.

Retrospective evaluation of admission total plasma protein as a predictor of red blood cell transfusion requirement in dogs diagnosed with traumatic and nontraumatic hemoabdomen: 90 dogs (2009-2019).

OBJECTIVE: To evaluate the association of admission total plasma protein (TPP) and the administration of red blood cell transfusions in dogs with diagnosed hemoabdomen. To secondarily evaluate additional point-of-care parameters associated with red blood cell transfusion administration. DESIGN: Retrospective study between 2009 and 2019. SETTING: University veterinary teaching hospital. ANIMALS: Ninety dogs admitted to a university veterinary teaching hospital after a diagnosis of traumatic or nontraumatic hemoabdomen (NTH). MEASUREMENTS AND MAIN RESULTS: Medical records were retrospectively reviewed; signalment, point-of-care diagnostics, and transfusion administration information was recorded. A total of 47 dogs (traumatic hemoabdomen 11/26; NTH 36/64) received packed red blood cell transfusions. For each 1 g/dL unit decrease in TPP, dogs had an increased odds ratio (OR) of 2.14 (95% confidence interval [CI]: 1.44-3.40, P < 0.001) of receiving a red blood cell transfusion. Dogs diagnosed with NTH were more likely to receive a red blood cell transfusion than dogs with a traumatic hemoabdomen (OR: 2.78, 95% CI: 1.11-7.141, P = 0.03). Lower PCV values (OR: 1.08, 95% CI: 1.04-1.12, P < 0.001), bicarbonate values (OR: 1.3, 95% CI: 1.09-1.56, P = 0.003), and base excess (OR: 1.27, 95% CI: 1.1-1.49, P = 0.003) were associated with a higher likelihood of red blood cell transfusion. Additionally, higher lactate (OR: 1.35, 95% CI: 1.16-1.63, P < 0.001) and Acute Patient Physiologic and Laboratory Evaluation (APPLE)fast scores (OR: 1.10, 95% CI: 1.04-1.17, P < 0.001) were associated with increased red blood cell transfusion administration. CONCLUSIONS: Low admission TPP, independent of low PCV, was associated with red blood cell transfusions regardless of underlying cause. For each 1 g/dL unit decrease in TPP on presentation, dogs were approximately 2 times more likely to receive a red blood cell transfusion during hospitalization. Other factors that were associated with increased transfusion administration included presenting PCV, PCV/TPP ratio, bicarbonate, base excess, lactate, and APPLEfast scores.

The effect of flow rate and catheter diameter on hemolysis during blood transfusions using canine packed red blood cells.

OBJECTIVE: To evaluate the degree of hemolysis in canine packed RBCs at varying catheter sizes and flow rates as determined by RBC count, Hct, hemoglobin, creatine phosphokinase, and phosphorus. This study hypothesized that changes in flow rate and catheter diameter would change the degree of hemolysis. SAMPLE: A fresh unit of canine RBCs. PROCEDURES: A fresh unit of purchased canine packed RBCs was run through an IV infusion pump through 5 different catheter sizes (16, 18, 20, 22, and 24 gauge) at 5 different rates (50, 250, 500, 750, and 999 mL/h). Each sample was submitted for a CBC and chemistry, and RBC count, hemoglobin, hematocrit, creatine phosphokinase, and phosphorus were specifically evaluated to assess for the degree of hemolysis. RESULTS: Compared to the control, flow rate did not significantly affect the degree of hemolysis. Smaller catheter sizes had a significantly increased hemolysis (P < .05) based on variables to evaluate hemolysis (RBC count, Hct, hemoglobin, creatine phosphokinase, and phosphorus). This study's hypothesis was upheld in association with the catheter diameter but was rejected with flow rate. CLINICAL RELEVANCE: Blood transfusions are a common practice in veterinary medicine as treatment of anemia and hemorrhage. Hemolysis was greater when small catheter sizes were used. Larger catheters are recommended when feasible when performing transfusions.

Effect of leukoreduction on inflammation in critically ill dogs receiving red blood cell transfusions: A randomized blinded controlled clinical trial.

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.

The effects of leukoreduction on canine blood unit weight and processing time.

BACKGROUND: Despite a lack of strong evidence of benefit, leukoreduction is employed to decrease the risk of leukocyte-induced transfusion reactions. However, the impact of leukoreduction on blood bank costs and inventory management is not well understood. The purpose of this study was to determine whether leukoreduction of whole blood increases total processing time and weight loss from packed red blood cells (PRBCs) and plasma relative to bags created from nonleukoreduced whole blood. KEY FINDINGS: A total of 68 canine whole blood collections were divided equally into leukoreduced and nonleukoreduced groups (N = 34 in each). There was no significant difference between groups in mean PRBC or plasma unit weights or processing times. Leukoreduced PRBC bags lost a significantly greater proportion of weight during processing than did nonleukoreduced PRBC bags (P < 0.01), which is attributed to red and white blood cells lost in the filtration process. SIGNIFICANCE: Leukoreduction did not lead to a significant increase in processing times or smaller PRBCs or plasma bags compared to nonleukoreduced bags. The blood remaining in the leukoreduction filter following filtration is primarily composed of red blood cells, with minimal plasma retained.

The influence of leukoreduction on the acute transfusion-related complication rate in 455 dogs receiving 730 packed RBCs: 2014-2017.

OBJECTIVE: To investigate the influence of prestorage leukoreduction of packed RBCs (pRBCs) on acute transfusion-related complication rate in dogs. SETTING: Two private referral hospitals. DESIGN: Retrospective case study. ANIMALS: Four hundred and fifty-five dogs receiving nonleukoreduced (nLR) or leukoreduced (LR) pRBC between January 1, 2014 and July 31, 2017. MEASUREMENTS AND MAIN RESULTS: Transfusions were retrospectively reviewed to record data about the patient, donor, unit, transfusion event, acute complications, hospital discharge, and cause of death. Of 730 transfusion events in 455 dogs, 288 used LR pRBC and 442 used nLR pRBC. There was a 18.9% (138/730) overall complication rate. Seven (0.96%) complications were life-threatening. The most common complications were pyrexia (5.6%), gastrointestinal signs (4.9%), and hemolysis with no other signs (4.1%). Pyrexia with no other clinical signs, consistent with a febrile nonhemolytic transfusion reaction (FNHTR), occurred in 3.2% of transfusion events. There was a significant (P = 0.03) decrease in the rate of FNHTR with LR pRBC (1%) versus nLR pRBC (4.5%). Use of LR pRBC did not decrease in-hospital mortality. The odds of any complication, hemolysis only, FNHTR, and more severe complications increased with pRBC age. Leukoreduction did not decrease the impact of pRBC age on these complications. Use of older pRBC did not increase the incidence of life-threatening complications or mortality. Dogs receiving pRBC for blood loss were more likely to have gastrointestinal and more severe complications than those dogs that had hemolysis. The effect of pRBC unit age on complications was not influenced by the underlying reason for transfusion. Dogs that received a previous transfusion were more likely to have respiratory complications. CONCLUSION: In this study, the use of LR pRBC was associated with a decreased rate of FNHTR but no other complications. Unit age was associated with the incidence of hemolysis, FNHTR, and complication severity but not the rate of life-threatening complications or mortality.

Randomized double-blinded clinical trial on acute transfusion reactions in dogs receiving leukoreduced versus nonleukoreduced packed red blood cells.

BACKGROUND: Leukoreduction of blood products is commonly performed in human medicine, but its effect on outcome or incidence of transfusion reactions (TRs) in dogs is unknown. OBJECTIVES: To prospectively evaluate the incidence of acute TRs in, and the outcome of, dogs receiving either leukoreduced (LR) or nonleukoreduced (N-LR) packed red blood cells (PRBC). ANIMALS: Dogs (n = 194) administered PRBC between August 2017 and June 2020. METHODS: Prospective randomized double-blinded clinical trial. Dogs were randomized to receive either LR or N-LR PRBC and clinicians, nurses and investigators were blinded to the group allocations. The incidence of TRs, change in PCV, hospitalization duration, and survival to discharge were recorded. RESULTS: Out of the 194 dogs, 96 received LR and 98 received N-LR PRBCs. The mean 12-hour change in PCV value was +9.22% (SD 5.27%) for dogs that received N-LR and +10.69% (SD 6.44%) for dogs that received LR PRBC (effect size 0.26, 95% confidence interval [CI] -0.02 to 0.55), which was not significantly different (P = .08). TRs were documented in 16/194 (8.24%) dogs, with 1/194 (0.51%) being a mild allergic reaction, while 15/194 (7.73%) had suspected febrile nonhemolytic TRs (FNHTRs). FNHTR incidence was not significantly different between the LR (6/96, 6.25%, 95% CI 2.8-13.56) and N-LR (9/98, 9.18%, 95% CI 4.92-17.11) groups (P = .81). Of the 156 dogs that survived to discharge, 80/156 received N-LR PRBC and 76/156 received LR PRBC which was not significantly different (P = .66). CONCLUSIONS AND CLINICAL IMPORTANCE: A clinical advantage of using LR over N-LR PRBC in terms of TRs and increase in PCV after transfusion was not detected.

Quantitative assessment of infusion pump-mediated haemolysis in feline packed red blood cell transfusions.

OBJECTIVES: Haemolysis caused by the use of peristaltic infusion pumps (PIPs) has been described in human and canine packed red blood cells (pRBCs). The aim of this study was to evaluate the effects of two different linear PIPs on the haemolysis of feline pRBC units stored for a long time. METHODS: Feline pRBC units stored with adenine, dextrose, mannitol and sodium chloride (SAGM) were manufactured. After 35-42 days of storage at 2-4°C, a line administration system with a 180 µm filter was attached to every pRBC bag, the system was drained by gravity alone (8 drops/min) and a 1.3 ml sample was collected (G). A NIKI V4 pump was then used at a flow rate of 25 ml/h, the flow was stopped when the infusion system was filled with blood coming from the infusion pump and another 1.3 ml sample was collected (NK). Finally, an Infusomat FmS pump was evaluated, collecting another 1.3 ml sample (IM). Packed cell volume (PCV) was measured in all samples by microhaematocrit centrifugation, total haemoglobin (HGB) was measured using a specific haemoglobin analyser and, after centrifugation, free HGB was determined by spectrophotometry. The percentage of haemolysis was calculated. Friedman's test was used to compare the samples. RESULTS: Fifteen feline pRBC units were evaluated. The average degree of haemolysis for sample G (gravity-assisted) was 1.12%. Comparison of the degree of gravity-assisted haemolysis with haemolysis in PIP NK (1.13%) and IM (1.14%) samples revealed no significant differences, with differences of only 0.01% and 0.02%, respectively. CONCLUSIONS AND RELEVANCE: The results of this study demonstrate that the use of two common PIPs in veterinary hospitals does not produce levels of haemolysis that are significantly different than that caused by gravity alone during transfusion of feline pRBCs at a rate of 25 ml/h.

The effect of time on packed cell volume following packed red blood cell transfusion in anemic dogs.

OBJECTIVE: To compare the PCV at several timepoints following packed red blood cell (pRBC) administration to anemic dogs and to assess if underlying cause of anemia or regenerative status significantly affects these measurements. DESIGN: Prospective, observational study from November 2016 to October 2017. SETTING: A small animal emergency and specialty hospital. ANIMALS: Forty-six anemic client-owned dogs that received a total of 50 pRBC transfusions for management of anemia. INTERVENTIONS: Blood was collected, and a PCV was obtained prior to pRBC transfusion (T0), immediately after (T1), 30 minutes after (T2), 1 hour after (T3), 2 hours after (T4), and 4 hours after (T5) the transfusion. Underlying causes of anemia were classified as hemorrhage, hemolysis, and ineffective erythropoiesis. Dogs were also categorized in regard to regenerative status of anemia and the presence or absence of expected continued blood loss or destruction. MEASUREMENTS AND MAIN RESULTS: The mean PCV at T0 was 0.15 L/L (15%). After administration of a pRBC transfusion, the mean PCV at T1 was 0.28 L/L (28%). For all other timepoints (T2, T3, T4, and T5), the mean PCV was 0.27 L/L (27%). The PCV did not change significantly over time post-transfusion (P = 0.184), and no pairwise combinations of times differed significantly (paired t-tests; P > 0.05 for all). When dogs were categorized via regeneration status and continued blood loss or hemolysis, results were consistent. CONCLUSIONS: There was no significant change in PCV from the value obtained immediately after pRBC transfusion up to 4 hours post-transfusion in dogs with several different causes of anemia. These results suggest that obtaining a PCV immediately after administering a pRBC transfusion to an anemic dog may be just as reliable as obtaining a measurement 2 hours after the transfusion. This remains true for dogs with expected continued red blood cell loss or destruction.

Retrospective evaluation of fresh frozen plasma use in 121 cats: 2009-2016.

OBJECTIVES: To document indications for fresh frozen plasma (FFP) use in cats, doses administered, and frequency of adverse transfusion reactions (ATR). DESIGN: Retrospective observational study from January 2009 to November 2016. SETTING: Large urban referral and emergency facility. ANIMALS: One hundred twenty-one client-owned cats that received FFP. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Signalment, indication(s), dose, pre- and posttransfusion total plasma protein, prothrombin time, activated partial thromboplastin time, as well as possible ATR, primary disease process, and outcome were recorded. Doppler blood pressure was increased posttransfusion (mean pre 99.5 ± 30.8 mm Hg; post 108.5 ± 32.5 mm Hg, P = .027). Cats were significantly less likely to be coagulopathic posttransfusion (P < 0.001). Most common indications were suspected coagulopathy (n = 105, 83%), hemorrhage (n = 45, 35%), and hypotension (n = 32, 25%). Median dose was 6 mL/kg (interquartile range = 3 mL/kg) and was negatively correlated with body weight (r = -.598, P < 0.001). Possible ATR occurred in 17 of 108 (16%, 95% confidence interval [CI], 10-24%) of transfusions. Increased body temperature was most common in 11 of 108 (10%, 95% CI, 5-18%), followed by tachypnea/dyspnea in 8 of 108 (7%, 95% CI, 3-13%). Common primary disease processes included liver disease (n = 41, 34%), neoplasia (n = 19, 16%), and sepsis (n = 15, 12%). Overall mortality was 54%. Improvement of clotting times was associated with increased odds of survival (odds ratio = 2.4; 95% CI, 1.1-5.3; P = 0.023). CONCLUSIONS: Clinician justifications for FFP transfusions are comparable to that reported in dogs; however, the mL/kg dose is lower. Coagulopathy and blood pressure significantly improve posttransfusion. Possible ATR were as frequent as that reported with feline packed RBCs transfusions and classified as mild.

Effect of packed red blood cell transfusion on thromboelastographic tracings in dogs with naturally occurring anemia.

OBJECTIVE: To assess the effect of packed RBC (pRBC) transfusion on thromboelastographic (TEG) tracings in dogs with naturally occurring anemia. ANIMALS: 22 clinically anemic dogs that received a pRBC transfusion. PROCEDURES: For each dog, a blood sample was collected before and within 3 hours after completion of the pRBC transfusion for a CBC, nonactivated TEG analysis, and measurement of blood viscosity. Wilcoxon signed rank tests were used to compare CBC, viscosity, and TEG variables between pretransfusion and posttransfusion blood samples. Multivariable linear regression was used to assess the effects of pretransfusion-posttransfusion changes in Hct, WBC count, and platelet count on changes in TEG variables. RESULTS: Median posttransfusion Hct (21%; range, 13% to 34%) was significantly greater than the median pretransfusion Hct (12.5%; range, 7% to 29%). Packed RBC transfusion was associated with a median increase in Hct of 6.2% (range, 1.2% to 13%). Maximum amplitude significantly decreased from 74.9 to 73.8 mm and clot strength significantly decreased from 14,906 to 14,119 dynes/s after pRBC transfusion. Blood viscosity significantly increased, whereas platelet and WBC counts significantly decreased after transfusion. Multivariable linear regression revealed that pretransfusion-posttransfusion changes in Hct, WBC count, and platelet count were not associated with changes in TEG variables. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that pRBC transfusion had only small effects on the TEG tracings of hemodynamically stable dogs. Therefore, large changes in TEG tracings following pRBC transfusion are unlikely to be the result of the transfusion and should be investigated further.

Exploration of risk factors for non-survival and for transfusion-associated complications in cats receiving red cell transfusions: 450 cases (2009 to 2017).

OBJECTIVES: To describe red blood cell transfusion practices and short-term outcomes in anaemic cats. To determine clinical variables associated with non-survival and transfusion-related complications. MATERIAL AND METHODS: In this retrospective study, blood bank records from the Ontario Veterinary College Health Science Centre (OVC-HSC) were reviewed to identify cats that received packed red blood cells or whole blood from 2009 to 2017. We extracted cause of anaemia, history of previous transfusion, pre- and post-transfusion packed cell volume, pre-transfusion compatibility testing, volume and dose of blood product, age of red blood cell unit, transfusion-associated complications and patient survival. RESULTS: A total of 450 transfusion events were recorded in 267 cats. Blood loss was the most common indication for blood transfusion (44.9%), followed by ineffective erythropoiesis (37.5%) and red blood cell destruction (22.5%). Transfusion-associated complications occurred in 10.2% events and there was a 20.2% mortality after transfusion. Mean increase in packed cell volume 24-hours after transfusion was greater in cats undergoing major cross-match testing before transfusion (7.2%) versus those that did not (4.0%). Non-survival was associated with higher packed cell volume before transfusion, low patient body temperature before transfusion, anaemia due to blood loss and number of transfusions administered. Older age of transfused blood units was associated with non-survival and transfusion-related complications. CLINICAL IMPORTANCE: This study was observational and so our analyses were exploratory, but suggest that major cross-match before transfusion tended to have greater transfusion efficacy and transfusion of older blood products might have detrimental effects on survival.

Successful xenotransfusion in a domestic ferret with spontaneous hemoperitoneum using feline packed red blood cells.

OBJECTIVE: To describe the diagnosis, management, and outcome of a ferret with spontaneous hemoperitoneum with surgical intervention and xenotransfusion of type A feline packed red blood cells (pRBCs). CASE SUMMARY: A domestic ferret diagnosed with a spontaneous hemoperitoneum secondary to a hepatic mass received isotonic crystalloids, hypertonic saline, and an allogenic blood transfusion perioperatively. Postoperatively, the ferret developed progressive anemia and tachycardia refractory to fluid therapy and, given a lack of additional allogenic blood sources, received a xenotransfusion of feline pRBCs. The ferret was hospitalized for 4 days postoperatively and developed a presumed delayed transfusion reaction characterized by transient hyperbilirubinemia. At a 6-month recheck, the ferret was doing well clinically. NEW OR UNIQUE INFORMATION PROVIDED: This is the first reported case of successful xenotransfusion of feline pRBCs in a ferret. Although xenotransfusion of ferrets with feline blood products is not recommended as a routine procedure, it remains a viable option in critical situations in which ferret blood is unavailable.

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.

Transfusion Medicine: An Update on Antigens, Antibodies and Serologic Testing in Dogs and Cats.

Red blood cell transfusions have become an integral component in the treatment of anemic patients and the number of transfusions continues to increase from year to year in both veterinary and human medicine. Although crucial, red blood cell transfusions are not benign and can lead to serious adverse reactions. Therefore, determining the most appropriate donor unit to use for transfusion can be challenging. As transfusion medicine evolves, greater numbers of blood surface antigens are being documented and pretransfusion testing protocols are becoming more complex. In order to better understand this evolving field, this review presents the basic immunology of pretransfusion testing, including methodologies of blood typing and crossmatch testing, and their application in canine and feline medicine.

Visual inspection of stored canine blood for hemolysis compared with measured plasma-free hemoglobin to assess suitability for transfusion.

Canine blood was visually inspected for hemolysis and compared with the Food and Drug Administration's standard of less than 1% hemolysis as measured by plasma-free hemoglobin. This was the basis for deciding to transfuse or dispose of stored canine blood. Free hemoglobin was measured in stored red blood cell units and compared to a calculated 1% hemolysis. Veterinarians and technicians determined if they would transfuse units based on visual inspection for hemolysis. Their evaluation was compared to the calculated hemolysis cutoff. The evaluations of veterinarians and technicians were significantly different from the mathematically derived cutoff. The technicians' visual assessments of the usability of samples were significantly different from those of the veterinarians: technicians more frequently judged the sample as unusable. Experienced veterinary personnel both over- and under-estimate the degree of hemolysis in stored canine RBCs. We recommend objective analysis of the amount of free hemoglobin in stored blood prior to transfusion.

Inspection visuelle du sang canin entreposé pour l'hémolyse comparativement à la mesure de l'hémoglobine libre pour évaluer sa qualité pour la transfusion. Du sang canin a été inspecté visuellement pour l'hémolyse et comparé à la norme de la Food and Drug Administration de moins de 1 % d'hémolyse mesurée par l'hémoglobine libre dans le plasma. Ce paramètre a été utilisé pour décider soit de faire la transfusion ou de jeter le sang canin entreposé. L'hémoglobine libre a été mesurée dans les unités de globules rouges entreposées et comparée à une hémolyse calculée à 1 %. Les vétérinaires et les techniciens ont déterminé s'ils effectueraient une transfusion des unités en se basant sur une inspection visuelle pour l'hémolyse. Leur évaluation a été comparée au seuil de coupure calculé pour l'hémolyse. Les évaluations des vétérinaires et des techniciens étaient significativement différentes du seuil dérivé des calculs mathématiques. Les évaluations visuelles des techniciens pour déterminer l'utilisabilité des échantillons étaient significativement différentes de celles des vétérinaires : les techniciens jugeaient plus fréquemment que les échantillons étaient inutilisables. Le personnel vétérinaire d'expérience surestime et sous-estime le degré d'hémolyse dans les globules rouges canins entreposés. Nous recommandons une analyse objective de la quantité d'hémoglobine libre dans le sang entreposé avant la transfusion.(Traduit par Isabelle Vallières).

Xenotransfusion with packed bovine red blood cells to a wildebeest calf (Connochaetes taurinus).

A 4-month-old female blue wildebeest (Connochaetes taurinus) was presented for bilateral pelvic limb fracture repair. Clinical examination under anaesthesia revealed a water-hammer pulse and a haematocrit of 0.13. A xenotransfusion was performed using bovine (Bos taurus) erythrocytes because of inability to acquire a wildebeest donor. Clinical parameters improved following transfusion and the post-operative haematocrit value was 0.31. The wildebeest remained physiologically stable with a gradually declining haematocrit for the next three days. On the third post-operative day, the wildebeest refractured its femur and was humanely euthanised because of the poor prognosis for further fracture repair. Xenotransfusion using blood from domestic ruminants represents a life-saving short-term emergency treatment of anaemic hypoxia in wild ungulates. Domestic goats could be used as blood donors for rare ungulates where allodonors are not available.

In vitro hemolysis of stored units of canine packed red blood cells.

BACKGROUND: Hemolysis is an important quality parameter of packed red blood cells (pRBCs) that is used to assess the cellular integrity of stored blood units. According to human standards, hemolysis at the end of storage must not exceed 1%, as otherwise it may be responsible for decreased transfusion effectiveness and acute life-threatening reactions. OBJECTIVES: This prospective study was designed to evaluate the hemolysis of canine pRBCs stored in an additive solution containing adenine, dextrose, mannitol, and sodium chloride, and to assess its associations with storage time, duration of the collection process, collection disturbances, and with the final volume and PCV of the pRBCs units. METHODS: One hundred eighty pRBCs units were collected from canine donors. Hemolysis of the pRBCs units was determined immediately after processing (t = 0). The units were then stored and retested (t = 1) either before administration (during weeks 2, 3, 4, 5, or 6 of storage) or at the end of the storage period (42 d) if not used. RESULTS: Mean hemolysis at t = 0 was 0.09% (SD 0.06) and increased during storage, at a more pronounced rate from the 5th (mean values of 0.52%, SD 0.29) to the 6th week (1.2%, SD 0.72). Almost 51% of the units with 36-42 days of shelf-life showed more than 1% hemolysis. Disturbances in the collection process, the volume of the whole blood units, and the volume of stored pRBCs units or their PCV were not related to pRBCs hemolysis. CONCLUSIONS: According to human blood bank recommendations regarding acceptable hemolysis, canine pRBCs stored for more than 35 days should be tested to ensure <1% hemolysis prior to administration.

Effects of Leukoreduction and Storage on Erythrocyte Phosphatidylserine Expression and Eicosanoid Concentrations in Units of Canine Packed Red Blood Cells.

BACKGROUND: Storage of canine packed red blood cells (pRBCs) can increase erythrocyte phosphatidylserine (PS) expression and eicosanoid concentrations. HYPOTHESIS/OBJECTIVES: To determine the effects of leukoreduction on erythrocyte PS expression and eicosanoid concentrations in stored units of canine pRBCs. Our hypothesis was that leukoreduction would decrease PS expression and eicosanoid concentrations. ANIMALS: Eight healthy dogs. METHODS: In a cross-over study, units of whole blood were leukoreduced (LR) or non-LR and stored (10 and 21 days) as pRBCs. Samples were collected at donation, and before and after a simulated transfusion. PS expression was measured by flow cytometry, and concentrations of arachidonic acid (AA), prostaglandin F2α (PGF2α ), prostaglandin E2 (PGE2 ), prostaglandin D2 (PGD2 ), thromboxane B2 (TXB2 ), 6-keto-prostaglandin F1α (6-keto-PGF1α ), and leukotriene B4 (LTB4 ) were quantified by liquid chromatography-mass spectrometry. RESULTS: There was no change in PS expression during leukoreduction, storage, and simulated transfusion for non-LR and LR units. Immediately after leukoreduction, there was a significant increase in TXB2 and PGF2α concentrations, but during storage, these eicosanoids decreased to non-LR concentrations. In both LR and non-LR units, 6-keto-PGF1α concentrations increased during storage and simulated transfusion, but there was no difference between unit type. There was no difference in AA, LTB4 , PGE2 , and PGD2 concentrations between unit types. CONCLUSIONS AND CLINICAL IMPORTANCE: Leukoreduction, storage, and simulated transfusion do not alter erythrocyte PS expression. Leukoreduction causes an immediate increase in concentrations of TXB2 and PGF2α , but concentrations decrease to non-LR concentrations with storage. Leukoreduction does not decrease the accumulation of 6-keto-PGF1α during storage.

Incidence of incompatible crossmatch results in dogs admitted to a veterinary teaching hospital with no history of prior red blood cell transfusion.

OBJECTIVE To determine the incidence of incompatible crossmatch results in dogs without a history of prior RBC transfusion and to evaluate changes in Hct following RBC administration for transfusion-naïve dogs that did and did not have crossmatching performed. DESIGN Retrospective study. ANIMALS 169 client-owned dogs. PROCEDURES Information obtained from the medical records included signalment, pretransfusion Hct or PCV, and crossmatching results where applicable. Dogs that underwent major crossmatching (n = 149) as part of pretransfusion screening were each crossmatched with 3 potential donors. Donor blood was obtained from a commercial source and tested negative for dog erythrocyte antigens (DEAs) 1.1, 1.2, and 7 but positive for DEA 4. Mean change in Hct after transfusion was compared between crossmatch-tested dogs (57/91 that subsequently underwent RBC transfusion) and 20 other dogs that underwent RBC transfusion without prior crossmatching by statistical methods. RESULTS 25 of 149 (17%) dogs evaluated by crossmatching were incompatible with 1 or 2 of the 3 potential donors. All 149 dogs were compatible with ≥ 1 potential donor. Mean ± SD change in Hct after transfusion was significantly higher in dogs that had crossmatching performed (12.5 ± 8.6%) than in dogs that did not undergo crossmatching (9.0 ± 4.3%). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated immunologic incompatibility can exist between first-time transfusion recipients and potential blood donor dogs. The clinical importance of these findings could not be evaluated, but considering the potential for immediate or delayed hemolytic transfusion reactions or shortened RBC life span, the authors suggest veterinarians consider crossmatching all dogs prior to transfusion when possible.