Retrospective evaluation of the effect of red blood cell product age on occurrence of acute transfusion-related complications in dogs: 210 cases (2010-2012)

A prospective multicenter observational study assessing incidence and risk factors for acute blood transfusion reactions in dogs

BACKGROUND

Reported incidence of blood transfusion reactions (TR) varies greatly.

OBJECTIVE

To prospectively evaluate the incidence of acute TRs in dogs receiving allogenic blood products, using consensus definitions, and to assess factors associated with TRs.

ANIMALS

Dogs (n = 858) administered allogenic blood products (n = 1542) between March and November 2022.

METHODS

Prospective, multicenter surveillance study occurring in referral hospitals in the United States, United Kingdom, and Australia recording TRs in dogs administered blood products as defined by the consensus guidelines published by The Association of Veterinary Hematology and Transfusion Medicine in 2021.

RESULTS

The incidence of acute TR was 8.9% (95% CI 7.0-11.1) for packed red blood cells (pRBCs) and 4.5% (95% CI 2.9-6.6) for plasma products. The most frequently reported TRs were febrile nonhemolytic TRs (FNHTR; 4%, 95% CI 2.8-5.5) when administering pRBCs and allergic TRs (3.2%, 95% CI 1.80-5.10) when administering plasma products. A higher dose of pRBC (adjusted odds ratio [aOR] 1.04 [95% CI 1.00-1.08]) was associated with a higher odds of TR. Administration of pRBCs stored for longer than 28 days was associated with higher odds of FNHTR (aOR 4.10 [95% CI 1.58-10.65]) and acute hemolytic TR (AHTR; OR 15.2 [95% CI 3.35-68.70]) when compared with pRBCs stored for 14 days or fewer. Leukoreduction of pRBC was not associated with lower odds of developing a TR (OR 1.47 [95% CI 0.89-2.42]).

CONCLUSIONS AND CLINICAL IMPORTANCE

Clinicians should be mindful of the age and dose of pRBC prescribed to dogs.

ACVIM consensus statement on the treatment of immune thrombocytopenia in dogs and cats

Management of immune thrombocytopenia (ITP) in dogs and cats is evolving, but there are no evidence-based guidelines to assist clinicians with treatment decisions. Likewise, the overall goals for treatment of ITP have not been established. Immunosuppressive doses of glucocorticoids are the first line treatment, but optimal treatment regimens beyond glucocorticoids remain uncertain. Additional options include secondary immunosuppressive drugs such as azathioprine, modified cyclosporine, and mycophenolate mofetil, usually selected based on clinician preference. Vincristine, human IV immunoglobulin (hIVIg), and transfusion of platelet or red blood cell-containing products are often used in more severe cases. Splenectomy and thrombopoietin receptor agonists are usually reserved for refractory cases, but when and in which patient these modalities should be employed is under debate. To develop evidence-based guidelines for individualized treatment of ITP patients, we asked 20 Population Intervention Comparison Outcome (PICO) format questions. These were addressed by 17 evidence evaluators using a literature pool of 288 articles identified by a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations. These were integrated by treatment domain chairs and then refined by iterative Delphi survey review to reach consensus on the final guidelines. In addition, 19 non-PICO questions covering scenarios in which evidence was lacking or of low quality were answered by expert opinion using iterative Delphi surveys with panelist integration and refinement. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The rigorous consensus process identified few comparative treatment studies, highlighting many areas of ITP treatment requiring additional studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Diagnosis of Immune Thrombocytopenia in Dogs and Cats.

Impact of a cell salvage device on blood transfusions to dogs undergoing surgery at a referral veterinary hospital

OBJECTIVE

To determine the number of homologous blood transfusions received by canine surgical patients after introducing a cell salvage device (CSD), trends in surgeries requiring blood transfusion, and the incidence of transfusion reactions.

STUDY DESIGN

Retrospective study.

SETTING

Single referral hospital.

ANIMALS

All dogs having surgery at a single center (November 2015 to February 2021).

INTERVENTIONS

Medical records of dogs having surgical treatment, including those that received either an autologous or homologous blood transfusion, were reviewed. The surgical patients were the baseline population, and the 2 transfusion groups were compared within this population to analyze the trends.

MAIN RESULTS

A total of 37 and 86 dogs received autologous and homologous blood transfusions, respectively. There was an upward trend in the number of total monthly blood transfusions. No significant increase in the monthly number of homologous transfusions was observed before or after acquisition of the CSD. There was also an upward trend in total monthly surgeries, including those with higher risks of hemorrhage. Dogs receiving homologous blood transfusions had a higher incidence of clinical signs consistent with transfusion reactions (6.98%).

CONCLUSIONS

An upward trend in autologous blood transfusions was seen with the introduction of a CSD. Hospitals with large surgical caseloads at high risk of hemorrhage may see a decreased need for outsourced blood products with the use of the CSD. The device can lead to a more responsible use of an increasingly scarce resource and decrease the risk of a blood transfusion reaction in dogs.

Evaluation of leukocyte depletion of packed red blood cell units and impact on clinically observed transfusion reactions

Introduction

The aim of this retrospective study was to determine whether there is an association between leukoreduction of packed red blood cell (pRBC) units and reduction of clinically observed transfusion reactions (TR), particularly febrile non-haemolytic transfusion reactions (FNHTR), and better outcomes in dogs. Secondary aims were to evaluate the effects of other factors suspected to influence transfusion reaction frequency or survival, including crossmatching, use of immunosuppressive drugs, and age and number of the blood products being administered.

Materials and methods

Medical data on dogs transfused with leukocyte-reduced (LR) and non-leukocyte-reduced (N-LR) pRBC units at the Animal Hospital Zürich, University of Zürich, Switzerland between January 1, 2007, and December 17, 2018 were searched. Before 2014, only N-LR blood were transfused. After 2014, both LR and N-LR blood were available.

Results

A total of 339 canine patients were transfused with 413 pRBC units; 30.5% (126/413) were LR units and 69.5% (287/413) were N-LR. Data collected from medical records was analyzed using univariate and multivariate logistic regression. In the present study, TR occurred in 19.8% of pRBC units (25/126) with LR and in 17.7% (51/287) of pRBC with N-LR; p > 0.05. FNHTR occurred in 6.3% of pRBC units (8/126) with LR and in 4.5% (13/287) of those with N-LR; p > 0.05. There was no correlation between the occurrence of TR and discharge from hospital (p > 0.05). Crossmatching, immunosuppressive therapy, and age of the blood product were not associated with the frequency of TR; p > 0.05 for all. The duration of survival days was not related to the number of transfusions dogs received.

Discussion

In the present study, the leukocyte-depletion of transfused pRBC units was not associated with fewer TR nor to fewer FNHTR compared to N-LR units. Discharge of dogs from hospital was not dependent on the occurrence of TR.

Retrospective evaluation of indications, transfusion protocols, and acute transfusion reactions associated with the administration of lyophilized canine albumin: 53 cases (2009-2020)

OBJECTIVES

To describe the administration of lyophilized canine albumin (LCA) and determine the increase in serum albumin concentrations post-LCA transfusion. To describe the incidence and types of acute transfusion reactions (TRs) and associated outcome in dogs presenting to a veterinary teaching hospital.

DESIGN

Retrospective and descriptive study from 2009 to 2020.

SETTING

University teaching hospital.

ANIMALS

Fifty-three client-owned dogs included in the study if they received an LCA transfusion and had vital sign monitoring recorded for at least for 4 hours after starting the LCA transfusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The 53 dogs available for study inclusion received 64 LCA transfusions. Signalment; underlying disease; indications for LCA transfusion; pre- and posttransfusion serum albumin concentration; volume, concentration, and dose of LCA; duration of transfusion; administration of other blood products or synthetic colloids; occurrence, timing, and type of TR; length of hospitalization; and outcome were recorded. Serum albumin concentrations increased post-LCA transfusion, with a median dose of 0.56 g/kg and a median posttransfusion serum albumin increase of 3 g/L (0.3 g/dL) (P = 0.008). TRs occurred in 13 of 64 (20.3%) transfusion events. Volume per kilogram, dose (g/kg), concentration, duration of transfusion, and additional administration of synthetic colloids were not associated with TRs. Three (23%) TRs were classified as febrile nonhemolytic transfusion reaction, 5 (38.5%) as transfusion-associated dyspnea (development of respiratory distress and limited diagnostics), and 5 (38.5%) had clinical signs that could not be defined by any 1 TR category. Six (46.1%) of 13 events were nonsevere, 5 (38.5%) were severe, and 2 (15.4%) were life-threatening.

CONCLUSIONS

Administration of LCA can be used to increase serum albumin concentrations, although the clinical implications of this increase are unknown. Acute TRs associated with LCA are relatively frequent and can be life-threatening. Careful monitoring is vital.

Retrospective study of canine blood xenotransfusion compared with type-matched feline blood allotransfusion to cats: indications, effectiveness, limitations and adverse effects

OBJECTIVES

Xenotransfusion is the transfusion of blood from one species to another. With varying availability of allogenic feline blood (AFB) and in emergency conditions, circumstances occur when canine blood is transfused to cats. This study aimed to characterise the indications, effectiveness, limitations, and acute and late transfusion-related adverse effects of canine blood xenotransfusion compared with matched AFB to anaemic cats, and their survival and longer-term outcome.

METHODS

This retrospective study (2013-2020) examined cats receiving canine blood xenotransfusions or AFB.

RESULTS

The study included 311 cats (xenotransfusion [X-group], n = 105; allotransfusion [A-group], n = 206). Xenotransfusion was more frequent among cats sustaining haemorrhage than in those with haemolysis (P <0.01) or hypoproliferative anaemia (P <0.001). Financial constraints were the most common reason to elect xenotransfusion (49%). The post-transfusion mean packed cell volume was higher (P <0.001) in the X-group (22%) compared with the A-group (18%), and also higher (P <0.001) at 48-96 h post-transfusion (23% vs 18%, respectively). Transfusion-related adverse effects (TRAEs) were more frequent (P = 0.001) in the X-group (37.1%) compared with the A-group (19.4%), as were delayed haemolytic transfusion reactions (85% vs 42.5%, respectively; P <0.001). Acute transfusion reactions (ATRs) were more frequent (P <0.001) in the A-group (60%) compared with the X-group (20%). TRAEs were unassociated with survival to discharge. The survival to discharge rate of the X-group (55%) was lower (P = 0.007) than in the A-group (73%), while post-discharge survival rates to 30 days of cats surviving to discharge were 90% and 88%, respectively (P = 0.85).

CONCLUSIONS AND RELEVANCE

Canine blood xenotransfusions to cats might save lives in emergency conditions when AFB is unavailable or blood typing is infeasible. The survival to discharge rate of the X-group was lower than that of the A-group. The longer-term survival rate of cats administered xenotransfusions and surviving to discharge from the hospital was good.

Effect of donor blood storage on gel column crossmatch in dogs

BACKGROUND

Compared with fresh blood, stored equine donor blood results in spurious tube crossmatch incompatibilities. Interpretation of blood crossmatch results is considered subjective.

OBJECTIVES

We aimed to determine if the duration of canine donor blood storage impacts compatibility testing using a standard gel column crossmatch and evaluate interobserver variation in the interpretation of crossmatch results.

METHODS

Observational study. Whole blood segments were obtained from 23 canine packed red blood cell (RBC) units for use in crossmatches after storage for 0, 7, 14, 21, 28, and 35 days. Major and minor crossmatches were performed using serum and RBCs, respectively, from two to three healthy "recipient" dogs per unit. All crossmatch results were interpreted by four observers, of whom three were blinded.

RESULTS

All major crossmatches (n = 61) were compatible on day 0 and remained compatible through day 35 of storage. All minor crossmatches (n = 69) were compatible at all time points, except for five donor pairs with 1 to 3+ agglutination. Repeat testing of these five donor pairs confirmed crossmatch incompatibilities on days 0 through 35, with no change in the degree of incompatibility over time. There was substantial agreement among four observers in determining compatibility (κ = 0.94) and scoring incompatibility (κ = 0.76).

CONCLUSIONS

The current practice of performing canine crossmatches with whole blood segments stored for up to 35 days is acceptable, with no spurious changes in compatibility expected over time. The substantial interobserver agreement suggests that the gel column is suitable for performing canine crossmatches in a laboratory setting with multiple personnel.

Ex vivo evaluation of a novel cell salvage device to recover canine erythrocytes

OBJECTIVE

To determine the ability of a cell salvage device to recover canine erythrocytes by direct aspiration of diluted packed red blood cells (pRBC) and saline rinse from blood-soaked surgical swabs.

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Twelve recently expired units of canine pRBC.

METHODS

pRBC units donated from a pet blood bank (after quality analysis) were diluted with anticoagulant, divided into two equal aliquots, and subsequently harvested by direct suction (Su), or soaked into swabs, saline-rinsed and suctioned (Sw). The volume of product, manual packed cell volume (PCV), and red blood cell mass (rbcM) were measured and compared before and after salvaging. The rbcM recovery was recorded as percentage ([rbcM post salvage]/[rbcM presalvage]x100). Statistical analysis of all measured values was performed (significance p < .05).

RESULTS

No difference was detected between pre- and post-salvage PCV or mean rise of PCV for either group. The volume of salvaged blood was 143 ml (SD ± 2.89 ml; Su) and 139.83 ml (SD ± 3.30 ml; Sw), p < .001. The average rbcM recovered was 88.43% (Su) and 84.74%. (Sw) averaged 84.74% (p = .015). Blood type and order of processing did not influence recovery.

CONCLUSION

The tested cell saver device reliably salvages canine blood in this ex vivo setting. Cell salvage via direct suction produces higher volumes of salvaged blood than rinsing blood-soaked swabs and salvaging the flush.

CLINICAL SIGNIFICANCE

Washing blood-saturated surgical swabs results in a high harvest of red blood cells. The authors recommend it as an adjunct to direct suction to maximize erythrocyte recovery.

Alloimmunization in dogs after transfusion: A serial cross-match study

BACKGROUND

Cross-matching is performed to determine the serological compatibility of donor and recipient blood. Current guidelines recommend that cross-matching should be performed in dogs when an initial transfusion was performed more than 4 days ago or when the transfusion history is unknown.

HYPOTHESIS

Determination at what time point alloantibodies are detected in dogs after transfusion. The hypothesis was that dogs would form alloantibodies within 4 days after a transfusion.

ANIMALS

Twenty-one anemic dogs were transfused and monitored for at least 4 subsequent days. Exclusion criteria were persistent red blood cell (RBC) agglutination and a previous transfusion.

METHODS

Prospective observational study. Cross-matching was performed before the initial DEA 1-compatible transfusion and on days 1, 2, 3, and 4 and if possible, between day 5 and 28, using the tube method without enhancement (major cross-match, recipient controls); recipients were monitored for transfusion reactions.

RESULTS

In 12/21 dogs a positive cross-match (microscopic degree of agglutination [AD] 1+ to 2+) was observed within 4 days after the transfusion. In a nonlinear regression model, no significant association was detected between type of anemia (P = .41), RBC storage time (P = .44), immunosuppressive treatment (P = .75) nor transfusion volume (P = .70) and the occurrence of positive cross-matches within 4 days after transfusion. Another 4 dogs developed a positive cross-match (microscopic AD 1+ to 2+) after 6 to 13 days.

CONCLUSIONS AND CLINICAL IMPORTANCE

Because production of alloantibodies was detected as early as 1 day after transfusion, cross-matching should be performed before every subsequent transfusion.

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.

Development and implementation of a hemovigilance program at a university veterinary teaching hospital

OBJECTIVE

To describe the development and implementation of a small animal hemovigilance program at a university veterinary teaching hospital.

DESIGN

Retrospective observational descriptive study performed between October 2014 and March 2019.

SETTING

University teaching hospital.

ANIMALS

Dogs and cats receiving blood product transfusions .

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

 A hemovigilance working group composed of veterinary specialists in clinical pathology, internal medicine, and emergency and critical care was established. This group developed evidence-based definitions of transfusion reactions, reaction classification systems, and a transfusion reaction reporting form. The reporting form contained sections for patient information, transfusion information, administration details, and reaction details. Reaction events were classified by reaction type, severity grade, and imputability to the transfusion. Following implementation of the hemovigilance program, transfusion reaction data were collected and examined for the period spanning October 2014 and March 2019. During the study period, 718 canine transfusions (4 whole blood, 400 packed RBC [pRBC], 300 fresh frozen plasma [FFP], 7 platelet rich plasma, and 7 cryoprecipitate) and 124 feline transfusions (5 whole blood, 95 pRBC, and 24 FFP) were administered. There were 32 total reactions (27 canine and 5 feline), with the most common reaction being febrile nonhemolytic transfusion reactions (19/32; 59%). The incidence rate of transfusion reactions was found to be 3.8% in dogs and 4.0% in cats. For the confirmed reactions, classification criteria for case definition, reaction severity grade, and imputability were able to be determined and recorded. This allowed targeted interventions to be implemented in order to potentially reduce future reactions.

CONCLUSIONS

A hemovigilance program can be instituted successfully in a veterinary hospital setting and once developed, standardized reporting tools could be utilized by multiple hospitals and provide the basis for more widespread reaction reporting in veterinary medicine.

Cross-sectional study of approaches to diagnosis and management of dogs with immune-mediated haemolytic anaemia in primary care and referral veterinary practices in the United Kingdom

OBJECTIVES

To determine whether veterinarians in primary care practices (PCPs) and board-certified clinicians (BCCs) approach treatment of dogs with immune-mediated haemolytic anaemia (IMHA) similarly, and whether practitioners with more experience treat similarly to those with less experience. We hypothesised those in PCPs would show more variation in their approach to similar cases than BCCs.

METHODS

A cross-sectional study was conducted by distributing a questionnaire to BCCs and veterinarians in PCPs. The questionnaire included direct questions and a number of clinical scenarios intended to capture approaches to common treatment problems.

RESULTS

Questionnaire responses were received from 241 veterinarians, including 216 in PCPs and 25 BCCs. Veterinarians in both settings used similar tests for diagnosis of IMHA, but BCCs performed more tests to exclude underlying causes of 'associative' disease. All veterinarians reported use of similar initial dosages of glucocorticoids (median 2 mg/kg per day in both groups, p = 0.92) but those used by more experienced practitioners were higher than those with less experience. Most veterinarians made allowances for the weight of dogs, using lower prednisolone dosages in a clinical scenario involving a 40 kg dog compared to a 9 kg dog (p = 0.025 for PCP, p = 0.002 for BCC). BCCs reported greater use of combinations of immunosuppressive drugs (p<0.0001) and of antithrombotic drugs (p<0.0001); use of antithrombotic drugs was also less common among more experienced practitioners compared to less experienced.

CONCLUSIONS

Approaches to treatment of dogs with IMHA differ between BCCs and those in PCP. These differences may affect design and implementation of future research studies and clinical guidelines.

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.

Association of Veterinary Hematology and Transfusion Medicine (AVHTM) Transfusion Reaction Small Animal Consensus Statement (TRACS). Part 1: Definitions and clinical signs

OBJECTIVE

To use a systematic, evidence-based consensus process to develop definitions for transfusion reactions in dogs and cats.

DESIGN

Evidence evaluation of the literature was carried out for identified transfusion reaction types in dogs and cats. Reaction definitions were generated based on synthesis of human and veterinary literature. Consensus on the definitions was achieved through Delphi-style surveys. Draft recommendations were made available through industry specialty listservs and comments were incorporated.

RESULTS

Definitions with imputability criteria were developed for 14 types of transfusion reactions.

CONCLUSIONS

The evidence review and consensus process resulted in definitions that can be used to facilitate future veterinary transfusion reaction research.

Association of Veterinary Hematology and Transfusion Medicine (AVHTM) Transfusion Reaction Small Animal Consensus Statement (TRACS) Part 2: Prevention and monitoring

OBJECTIVE

To systematically review available evidence to develop guidelines for the prevention of transfusion reactions and monitoring of transfusion administration in dogs and cats.

DESIGN

Evidence evaluation of the literature (identified through Medline searches through Pubmed and Google Scholar searches) was carried out for identified transfusion reaction types in dogs and cats. Evidence was evaluated using PICO (Population, Intervention, Comparison, Outcome) questions generated for each reaction type. Evidence was categorized by level of evidence (LOE) and quality (Good, Fair, or Poor). Guidelines for prevention and monitoring were generated based on the synthesis of the evidence. Consensus on the final recommendations and a proposed transfusion administration monitoring form was achieved through Delphi-style surveys. Draft recommendations and the monitoring form were made available through veterinary specialty listservs and comments were incorporated.

RESULTS

Twenty-nine guidelines and a transfusion administration monitoring form were formulated from the evidence review with a high degree of consensus CONCLUSIONS: This systematic evidence evaluation process yielded recommended prevention and monitoring guidelines and a proposed transfusion administration form. However, significant knowledge gaps were identified, demonstrating the need for additional research in veterinary transfusion medicine.

Association of Veterinary Hematology and Transfusion Medicine (AVHTM) transfusion reaction small animal consensus statement (TRACS). Part 3: Diagnosis and treatment

OBJECTIVE

To systematically review available evidence to develop guidelines for diagnosis and treatment of transfusion-associated reactions in dogs and cats.

DESIGN

Standardized and systemic evaluation of the literature (identified through Medline via PubMed and Google Scholar searches) was carried out for identified transfusion reaction types in dogs and cats. The available evidence was evaluated using PICO (Population, Intervention, Comparison, Outcome) questions generated for each reaction type. The evidence was categorized by level of evidence (LOE) and quality (Good, Fair, or Poor). Guidelines, diagnostic, and treatment algorithms were generated based on the evaluation of the evidence. Consensus on the final guidelines was achieved through Delphi-style surveys. Draft recommendations were disseminated through veterinary specialty listservs for review and comments, which were evaluated and integrated prior to final publication.

RESULTS

Medline via PubMed and Google Scholar databases were searched. There were 14 Population Intervention Comparison Outcome questions identified and corresponding worksheets were developed focusing on the diagnosis and treatment of transfusion-associated reactions in dogs and cats. Fourteen guidelines and four algorithms were developed with a high degree of consensus.

CONCLUSIONS

This systematic evidence evaluation process yielded recommended diagnostic and treatment algorithms for use in practice. However, significant knowledge gaps were identified, demonstrating the need for additional research in veterinary transfusion medicine.

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.

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.

Therapeutic Strategies for Treatment of Immune-Mediated Hemolytic Anemia

Immune-mediated hemolytic anemia is a common hematologic disorder in dogs. Disease management involves immunosuppression using glucocorticoids, potentially in combination with other medications such as azathioprine, cyclosporine, or mycophenolate mofetil. Therapeutic drug monitoring may enhance the utility and maximize the safety of cyclosporine and mycophenolate mofetil. The disease is proinflammatory and prothrombotic. Antithrombotic drug administration is therefore essential, and anticoagulant therapy should be initiated at the time of diagnosis. Additional therapies include red blood cell transfusion to support blood oxygen content. Future therapies may include therapeutic plasma exchange, anti-CD20 monoclonal antibodies, and complement inhibitors.

Small Animal Transfusion Medicine

Transfusion medicine can be a lifesaving intervention. Component therapy has expanded the availability and blood products available. Patient safety and minimizing risk is important and can be accomplished through proper donor screening, collection, storage, compatibility testing, administration, and monitoring. The pros and cons of available products must be considered and tailored to each individual patient. Recent discoveries include new antigens and blood types, microbial effects on blood type, and the association between blood type and disease prevalence.

Retrospective evaluation of the indications, safety and effects of fresh frozen plasma transfusions in 36 cats (2014-2018)

OBJECTIVES

The goals of this study were to classify the indications, risks, effects on coagulation times and outcomes of cats receiving fresh frozen plasma (FFP) transfusions in clinical practice.

METHODS

This was a retrospective study of FFP transfusions administered in two referral hospitals from 2014 to 2018. Transfusion administration forms and medical records were reviewed. Information was collected on indication, underlying condition, coagulation times and signs of transfusion reactions. Seven-day outcomes after FFP administration were also evaluated when available.

RESULTS

Thirty-six cats received 54 FFP transfusions. Ninety-four percent of cats were administered FFP for treatment of a coagulopathy. Twenty cats had paired coagulation testing before and after FFP administration. Eighteen of these cats had improved coagulation times after receiving 1-3 units of FFP. Eight of the 36 cats had probable transfusion reactions (14.8% of 54 FFP transfusions). These reactions included respiratory signs (n = 4), fever (n = 2) and gastrointestinal signs (n = 2). Five of the eight cats with probable reactions had received packed red blood cells contemporaneously. Overall mortality rate during hospitalization was 29.7%, with 52.8% (n = 19/36) of cats confirmed to be alive 7 days after discharge.

CONCLUSIONS AND RELEVANCE

This retrospective study shows that FFP transfusions improve coagulation times in cats. Transfusion reactions are a risk, and risk-benefit ratios must be measured prior to administration and possible reactions monitored. In the study cats, the FFP transfusions appeared to be a tolerable risk given the benefit to prolonged coagulation times.

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.

Evaluation of hematologic, biochemical, and blood gas variables in stored canine packed red blood cells, and the impact of storage time on blood recipients

BACKGROUND

Canine packed red blood cells (pRBCs) can be stored under refrigeration for several days; however, cellular metabolism remains active inside the units, thus producing substances that affect their quality.

OBJECTIVES

We aimed to evaluate hematologic, biochemical, and blood gas variable alterations that occur in canine pRBCs during storage, and their effects on recipient clinicopathologic parameters.

METHODS

The study was conducted in two phases. In phase I, 15 pRBC units containing CPDA-1 were stored for 28 days; samples were collected weekly from the units of days 0 to 28 to measure the packed cell volume (PCV), pH, partial pressure carbon dioxide (PCO₂ ), partial pressure oxygen (PO₂ ), concentrations of lactate and potassium, and the percent hemolysis. In phase II, another 22 canine pRBC units stored for different time periods (maximum of 21 days) were transfused, and the recipients were evaluated before and after transfusion for changes in clinical parameters (heart rate, respiratory rate, systolic arterial pressure, and rectal temperature) and hematologic variables (PCV, lactate and potassium concentrations, pH, PCO₂ , the ratio of arterial oxygen partial pressure to fractional inspired oxygen [PO₂ /FiO₂ ] ratio, oxygen saturation [SaO₂ ], base excess, and bicarbonate [HCO₃ ]).

RESULTS

In the pRBC units, the PCV increased from 70% to 78.33%, the lactate concentration increased 627%, the potassium concentration increased 183%, the percent hemolysis reached 0.69%, and the pH decreased 9% after 28 days. However, the dogs who received transfusions were not negatively affected. There was a significant increase in PCVs, and a significant decrease in heart rates.

CONCLUSION

Canine pRBCs undergo hematologic, blood gas, and biochemical alterations during storage; however, the transfusion of pRBCs stored for up to 21 days increased PCVs without causing harm to the dogs.

Autotransfusão imediata em cão - relato de caso

RESUMO As hemorragias podem levar à morte, em caso de não interrupção e recuperação da volemia. A substituição do sangue pode ser realizada por transfusão homóloga ou autóloga. Na transfusão homóloga, o sangue é obtido de um doador, na autotransfusão ou transfusão autóloga, o sangue é coletado do próprio paciente. Objetivou-se relatar a autotransfusão em um cão como um método simples, rápido e barato, e discutir esse procedimento como uma alternativa emergencial para clínicas e hospitais que não possuem bancos de sangue ou animais doadores. Foi atendido um cão Rottweiler fêmea, 42,8kg, 10 anos de idade, com queixa principal de tumor mamário e para realização de castração. Após o procedimento, a paciente apresentou hemoperitônio, sendo encaminhada para novo procedimento cirúrgico, durante o qual se observou grande quantidade de sangue livre na cavidade abdominal. Foi realizada a autotransfusão de emergência, pela técnica das duas seringas, devido à indi1111sponibilidade de sangue ou animal doador no momento do procedimento cirúrgico emergencial, demonstrando ser uma opção eficiente, econômica, de fácil acesso e segura, por ser uma transfusão normotérmica, apresentar diminuição do risco de sobrecarga circulatória e por ser o sangue compatível, devendo ser mais explorada, pois existem poucos dados descritos na literatura.

Haematological and morphological evaluation of feline whole blood units collected for transfusion purposes

OBJECTIVES

Despite the increasing availability of feline blood collected and stored for transfusion purposes, few studies have been performed on feline blood units. The aim of this prospective in vitro study was to evaluate haematological and morphological changes in feline blood cells in whole blood units between collection and end of storage.

METHODS

Haematological examination (red blood cells [RBCs], haemoglobin, haematocrit, red cell distribution width, mean cell volume, mean cell haemoglobin concentration, mean cell haemoglobin, white blood cells [WBCs] and platelet [PLT] count) was performed on 40 non-leukoreduced feline whole blood units at the time of collection (day[D]0) and after storage (D35). The blood was collected into citrate-phosphate-dextrose-adenine anticoagulant-preservative solution using an open system in a veterinary blood bank and stored for 35 days at 4 ± 2°C. Twenty of these feline whole blood units were also analysed for blood cell morphology (normal RBCs, macrocytes, echinocytes, spherocytes, schistocytes, lysed RBCs, RBCs with Heinz bodies and recognisable WBC and PLT count). Differences between the two examination times were statistically analysed.

RESULTS

There was a statistically significant decrease in WBC and PLT counts after storage at D35 (P <0.0001 for both). The most significant cellular morphological changes after storage were an increase in echinocyte count (P = 0.0001), and lysed RBCs (P <0.0001), and a decrease in normal RBCs (P <0.0001). Recognisable WBCs - mainly lymphocytes - were present at the end of storage.

CONCLUSIONS AND RELEVANCE

This study showed that significant morphological changes occur in RBCs in feline blood units during storage for 35 days. In vivo studies are required to establish if these changes could affect the ability of stored RBCs to circulate and provide adequate oxygen delivery after transfusion.

ACVIM consensus statement on the treatment of immune-mediated hemolytic anemia in dogs

Immune‐mediated hemolytic anemia (IMHA) causes severe anemia in dogs and is associated with considerable morbidity and mortality. Treatment with various immunosuppressive and antithrombotic drugs has been described anecdotally and in previous studies, but little consensus exists among veterinarians as to the optimal regimen to employ and maintain after diagnosis of the disease. To address this inconsistency and provide evidence‐based guidelines for treatment of IMHA in dogs, we identified and extracted data from studies published in the veterinary literature. We developed a novel tool for evaluation of evidence quality, using it to assess study design, diagnostic criteria, explanation of treatment regimens, and validity of statistical methods. In combination with our clinical experience and comparable guidelines for humans afflicted with autoimmune hemolytic anemia, we used the conclusions of this process to make a set of clinical recommendations regarding treatment of IMHA in dogs, which we refined subsequently by conducting several iterations of Delphi review. Additionally, we considered emerging treatments for IMHA in dogs and highlighted areas deserving of future research. Comments were solicited from several professional bodies to maximize clinical applicability before the recommendations were submitted for publication. The resulting document is intended to provide clinical guidelines for management of IMHA in dogs. These guidelines should be implemented pragmatically, with consideration of animal, owner, and veterinary factors that may vary among cases.

Effects of irradiation and leukoreduction on down-regulation of CXCL-8 and storage lesion in stored canine whole blood

White blood cells (WBCs) and storage period are the main factors of transfusion reactions. In the present study, cytokine/chemokine concentrations after leukoreduction (LR) and irradiation (IR) in stored canine whole blood were measured. Red blood cell storage lesion caused by IR and LR were also compared. Blood samples from 10 healthy Beagles were divided into four groups (no treatment, LR-, IR-, and LR + IR-treated). Leukocytes were removed by filtration in the LR group and gamma radiation (25 Gy) was applied in the IR group. Immunologic factors (WBCs, interleukin-6 [IL-6], C-X-C motif chemokine ligand 8 [CXCL-8], and tumor necrosis factor-alpha) and storage lesion factors (blood pH, potassium, and hemolysis) were evaluated on storage days 0, 7, 14, 21, and 28. Compared to the treated groups, IL-6 and CXCL-8 concentrations during storage were significantly higher in the control (no treatment) group. LR did not show changes in cytokine/chemokine concentrations, and storage lesion presence was relatively mild. IR significantly increased CXCL-8 after 14 days of storage, but IR of leukoreduced blood did not increase CXCL-8 during 28 days of storage. Storage lesions such as hemolysis, increased potassium, and low pH were observed 7 days after IR and storage of blood, regardless of LR. IR of leukoreduced blood is beneficial to avoid immune reactions; however, storage lesions should be considered upon storage.

In vitro assessment of quality of citrate-phosphate-dextrose-adenine-1 preserved feline blood collected by a commercial closed system

BACKGROUND

Optimal procedure for storage of feline blood is needed. Open-collection systems have been employed in feline medicine, thus limiting the possibility for storage.

OBJECTIVES

To evaluate indicators of quality of feline blood stored for 35 days at +4°C in a closed-collection system specifically designed for cats.

ANIMALS

Eight healthy adult European domestic shorthair cats with a weight of 5-6.8 kg.

METHODS

This is a case series study. A bacteriological test, CBC, blood smear, pH, osmotic fragility, 2,3-diphosphoglycerate (2,3-DPG), and adenosine triphosphate (ATP) measurement were performed weekly on whole blood (WB) units from day 1 to day 35 after donation. The hemolysis index, lactate and potassium concentrations, prothrombin time (PT), activated partial thromboplastin time (aPTT), and fibrinogen were measured on plasma aliquots.

RESULTS

One out of eight blood units (BUs) had bacterial growth (Serratia marcescens) at day 35. No significant differences were found regarding CBC, morphology, pH, and osmotic fragility. Despite high inter-individual variability and low starting levels, significant decreases in the mean concentrations of 2,3-DPG (T0 1.99 mmol/g Hb, SD 0.52, T35 1.25 mmol/g Hb, SD 1.43; P = .003) and ATP (T0 1.45 mmol/g Hb, SD 0.71, T35 0.62 mmol/g Hb, SD 0.51; P < .001) were detected during the study, as opposed to an increase in hemolysis (T0 0.11 mmol/L, SD 0.07, T35 0.84 mmol/L, SD 0.19; P < .001), lactate (T0 3.30 mmol/L, SD 0.86, T35 13.36 mmol/L, SD 2.90; P < .001), and potassium (T0 3.10 mmol/L, SD 0.21, T35 4.12 mmol/L, SD 0.35; P < .001) concentrations.

CONCLUSIONS AND CLINICAL IMPORTANCE

The commercial BU kit is appropriate for blood collection and conservation of WB in cats. The maintenance of WB quality indicators during storage is essential for future improvements of feline transfusion medicine.