34th Annual Scientific Meeting proceedings

Introduction: Emergency abdominal surgery has high rates of morbidity and mortality. Effective markers to predict patient outcome would be desirable. This study aims to determine the relationship between mortality and length of hospitalization with neutrophil-to-lymphocyte (NLR), platelet-to-lymphocyte (PLR), monocyte-to-lymphocyte (MLR) ratios, and the systemic immune-inflammatory index (SII) in patients undergoing emergency abdominal surgery.

Materials and Methods: This retrospective study included 175 dogs divided into two groups: dogs undergoing emergency abdominal surgery (n=125) and a control group of healthy dogs (n=49). Preoperative NLR, PLR, MLR, and SII were determined and compared between i) study and control group, ii) survivors and non-survivors, and iii) dogs with short (< 5 days) and long (> 5 days) postoperative hospitalization time. Mann-Whitney U test was used. The area under the curve (AUC) value and optimal cutoff value was determined using receiver operating characteristic (ROC) curves.

Results: NLR, MLR, and SII values were higher in dogs undergoing emergency abdominal surgery than in healthy dogs. NLR and SII did not differ between survivors and non-survivors, or between short or long hospitalization. Only preoperative MLR was associated with longer hospitalization time (P<0.01) and mortality (P<0.001). As a predictor of mortality the AUC of the MLR was 0.91 ([CI: 0.86-0.97]; P=0.0001) and the cut-off value was 1.5  (sensitivity 94%; specificity 80%).

Discussion: Dogs undergoing emergency abdominal surgery with preoperative MLR>1.5 are at increased risk for mortality. NLR, PLR, and SII were not associated with increased mortality or hospitalization length.