Plasma lactate as a predictor of colonic viability and survival after 360 degrees volvulus of the ascending colon in horses.

Abstract

OBJECTIVES: To determine the relationship between plasma lactate concentration and colonic viability and survival in horses with >or=360 degrees volvulus of the ascending colon. STUDY DESIGN: Retrospective study. ANIMALS: Horses (n=73) with >or=360 degrees volvulus of the ascending colon. METHODS: Medical records (January 2000-November 2005) of all horses examined for colic at Michigan State University Veterinary Teaching Hospital were reviewed. Horses were included only if plasma lactate concentration was measured preoperatively and a diagnosis of >or=360 degrees volvulus of the ascending colon was confirmed by surgery or necropsy. Non-survivors were only included if the ascending colon was evaluated histopathologically. Logistic regression analysis was used to model the relationship between lactate, colonic viability, and survival. RESULTS: Of 73 horses, 61 were discharged. Mean (+/-SD) plasma lactate concentration was significantly lower in survivors (2.98+/-2.53 mmol/L) compared with non-survivors (9.48+/-5.22 mmol/L; odds ratio [OR]=1.628, 95% confidence limit [CI]=1.259-2.105). Plasma lactate concentration was significantly lower in horses with a viable colon (3.30+/-2.85 mmol/L) compared with horses with a non-viable colon (9.1+/-6.09 mmol/L; OR=1.472, 95% CI=1.173-1.846). Plasma lactate concentration <6.0 mmol/L had a sensitivity of 84% and a specificity 83% for predicting horse survival. CONCLUSIONS: Our results demonstrate a strong association between plasma lactate concentration at the time of hospital admission and outcome in horses with >or=360 degrees volvulus of the ascending colon. CLINICAL RELEVANCE: Plasma lactate concentration may help predict colonic viability and horse survival after ascending colon volvulus in horses.