Overview of Clinical Pathology and the Horse

Blood Transfusion in Equids—A Practical Approach and Review

Simple Summary

Transfusion medicine is an accessible, technically simple, and often lifesaving tool that can be used in both field and hospital settings, in cases of significant bleeding or anemia. A thorough understanding of the indications, methodology and complications of blood transfusion allows the practitioner to identify cases where administration of whole blood is necessary, and how to safely perform the transfusion. This review collects the current literature surrounding blood transfusion into one readily accessible document to allow clinicians a comprehensive understanding of all aspects of equine blood transfusion, while serving as a reference for performing these procedures.

Abstract

Transfusion medicine is a crucial part of equine intensive and critical care. Blood transfusions can save lives in both acute and chronic cases of anemia, hemorrhage, and hemolysis. It is vital to have a comprehensive theoretical and practical understanding of the techniques, implications, risks, and complications. This review covers the physiology and pathophysiology of conditions requiring transfusion, as well as step by step guidance for practitioners of all experience levels. This review is designed to serve as a practical reference for those who are treating horses in either the field or hospital setting. It aims to provide both theoretical background and easy to locate formulae with guidance that is easy to refer to in a critical situation. When risks and benefits are well understood, these techniques can be confidently employed in critical situations to improve outcomes and save lives.

Influence of multiple factors on hematologic reference intervals in horses residing in livery yards in Spain

The hemogram is a routine analysis for equine veterinary practitioners in the assessment of patient clinical status. Reference intervals (RIs) of hematologic constituents vary according to different horse populations and are often described for a particular breed or horse type. The aims of this study were to determine RIs for hematologic constituents in a mixed-breed horse population residing in livery yards in central Spain and evaluate the associations between estimated RIs and multiple phenotypic and management characteristics. A total of 122 healthy horses from different breeds in central Spain were included in the study. RIs were calculated following the American Society for Veterinary Clinical Pathology guidelines. Significant associations between red blood cell (RBC) counts, packed cell volumes (PCVs), hemoglobin (HGB) concentrations, white blood cell (WBC) counts, and phenotypic and management features were evaluated using a novel multiple linear regression model analysis. Reference intervals were 5.8-10.0 × 10¹² /L for RBCs, 97-164 g/L for HGB, 0.27-0.46 L/L for PCVs, 37.1-53.6 fL for MCVs, 3.8-10.8 × 10⁹ /L for WBCs, and 76.1-377.9 × 10⁹ /L for platelet counts. The season, discipline, and housing when and where the horses were sampled were factors significantly associated with WBC counts and/or red cell values (HGB, RBC, and PCV). Hematologic RIs for these horses were comparable to the RIs of warm-blooded horses and influenced by husbandry. These location-specific RIs should allow veterinary practitioners to make better-informed decisions for their patients residing in livery yards.