Association of Presence of Band Cells and Toxic Neutrophils with Systemic Inflammatory Response Syndrome and Outcome in Horses with Acute Disease

BackgroundBand cells and toxic neutrophils are thought to indicate acute and severe systemic illness but no studies have investigated their importance in adult equine emergency admissions. ObjectivesThe objective of this study was to evaluate the association of band cells and toxic neutrophils with systemic inflammatory response syndrome (SIRS) and outcome in horses. AnimalsOne hundred and five adult horses admitted on emergency basis to a private primary referral practice. MethodsProspective observational study with sample collection. All horses admitted on emergency basis over the study period were included in the study if they had a CBC and a blood smear collected on admission. ResultsThe detection of band neutrophils on admission was associated with the SIRS status of the horse (RR = 2.80; 95% CI = 1.57-4.99; P < .001) and with poor outcome (RR = 1.88; 95% CI: 1.05-3.37; P = .038). Similarly, the presence of a neutrophil toxic grade higher than 3 was associated with SIRS (RR = 1.71; 95% CI: 1.03-2.82; P = .034) and death (RR = 2.34; 95% CI: 1.22-4.50, P = .007). The information gained from the blood smear review could not be captured by looking at only the WBC or neutrophil count. Conclusions and Clinical ImportanceThe microscopic review of blood smears from critically ill horses to detect band cells or neutrophil toxic change is valuable and could help in assessing disease severity and prognosis in adult equine emergency admissions.