Xenotransfusion of Blood from Dog to Cat: Should Canine Blood Be Our First Choice for Feline Transfusion in Emergency Situations?

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.

Incidence of acute haemolysis in cats receiving canine packed red blood cells (xenotransfusions)

OBJECTIVES

The aim of this study was to report the incidence of transfusion reactions in cats, including acute haemolysis (AH), occurring within 24 h of receiving a xenotransfusion. An additional aim was to determine whether cases with AH could be classified as having an acute haemolytic transfusion reaction (AHTR) as per the definition provided by the Association of Veterinary Haematology and Transfusion Medicine's Transfusion Reaction Small Animal Consensus Statement.

METHODS

Medical records of cats that received canine packed red blood cells (PRBCs) between July 2018 and September 2020 at a veterinary hospital were reviewed. The incidence of AH, AHTRs, febrile non-haemolytic transfusion reactions (FNHTRs), transfusion-associated circulatory overload and septic transfusion reactions were recorded.

RESULTS

The medical records of 53 cats were retrospectively evaluated. Twenty-three (43%) cats had transfusion reactions. Thirteen (25%) cats had AH; however, only four (8%) met the definition of an AHTR. Ten (19%) cats were determined to have FNHTRs. Survival to discharge of cats affected by AH was 50% (25% for cases that met the definition of an AHTR). Survival to discharge of cats not suffering from AHTR was 40%.

CONCLUSIONS AND RELEVANCE

This report indicates that a higher proportion of cats undergo AH (25%) when administered canine PRBCs than previously reported, although many could not be classed as having an AHTR due to an apparently adequate packed cell volume rise. Challenges with sourcing feline blood in emergency situations occasionally necessitates the use of xenotransfusion in transfusion medicine. Clinicians should be aware that haemolysis after xenotransfusion can occur within 24 h and that a repeat feline transfusion may be required sooner than anticipated in some cases.