Prognostic value of colonic and peripheral venous lactate measurements in horses with large colon volvulus

OBJECTIVE: To determine the prognostic value of (1) colonic venous lactate or peripheral lactate values obtained before and after manual correction of a large colon volvulus and (2) a combination of variables including pelvic flexure biopsy. STUDY DESIGN: Prospective clinical study. ANIMALS: Forty adult horses in which large colon volvulus was diagnosed intraoperatively. METHODS: Colonic venous, peripheral venous, and arterial blood samples were collected to measure lactate values before and after manual correction. Mucosal biopsy samples were obtained in cases that underwent enterotomy or colonic resection and anastomosis. Interstitium to crypt (I:C) ratio and hemorrhage scores were measured. Optimal cutoff values were determined by receiver operator curve analysis, and associations between variables and short-term outcome were determined by univariable regression. Short-term survival was defined as horses being discharged from the hospital. P /=3.2 mmol/L and after manual correction >/=5 mmol/L, arterial lactate postmanual correction >/=3.53 mmol/L, and histomorphometric measurements of mucosal hemorrhage >/=3 and I:C ratio > 1 were associated with poor short-term outcome. CONCLUSION: Peripheral lactate values, histomorphometric measures of I:C ratio, and hemorrhage score provided prognostic information that could help guide recommendations made to owners. CLINICAL SIGNIFICANCE: Peripheral lactate values after manual correction provide important intraoperative diagnostic information to assist in predicting case outcome in the operative and immediately postoperative period.