Neutrophil-to-lymphocyte ratio, nucleated red blood cells and erythrocyte abnormalities in canine systemic inflammatory response syndrome

Systemic inflammatory response syndrome (SIRS) is the manifestation of the systemic response to an infectious or non-infectious disease. We evaluated the association between erythrocyte parameters, including nucleated red blood cells (NRBCs) and leukocyte ratios (NLR, neutrophil-to-lymphocyte ratio; BLR, band neutrophil-to-lymphocyte ratio; BLNR, band neutrophil-to-neutrophil-to-lymphocyte ratio). A review of the medical records was conducted searching SIRS dogs among those admitted to our intensive care unit and a SIRS grading was obtained based on how many criteria were fulfilled. The Acute Patient Physiology and Laboratory Evaluation (APPLEfast) score was assessed in each dog. Survival rate was assessed 15 days after admission. Dogs with clinical and/or clinicopathological signs of hemolytic or hemorrhagic disorders were excluded. Dogs with ≥2 criteria of SIRS along with a documented underlying infectious cause were recorded as septic (32/90, 35%). A SIRS grading >2 (p =.001) and an APPLEfast score > 25 (p =.03) were associated with mortality. Twenty-two of SIRS dogs (24%) showed circulating NRBCs. The occurrence of circulating NRBCs was associated with the mortality in SIRS groups (p =.0025). The median NLR was 11.69 and NLR was lower in septic dogs compared to non-septic ones (p =.0272). APPLEfast, SIRS grading and circulating NRBCs may be considered as negative prognostic factors in canine SIRS. NLR could be a useful tool in dogs with SIRS, which was significantly lower in the septic group. Further prospective, large-scale studies investigating BLR and BNLR in canine SIRS are warranted.