Abnormalities in oxygenation, coagulation, and fibrinolysis in colonic blood of horses with experimentally induced strangulation obstruction

Abstract

Abstract Objective To measure arterial and venous blood gas, coagulation, and fibrinolysis variables in blood from isolated segments of control and ischemic large colons for the purpose of identifying variables for rapid, indirect assessment of colonic mucosal injury. Design Variables were determined at specific intervals during the 4-hour study (3 hours of ischemia and 1 hour of reperfusion). Animals Seven clinically normal horses between 2 and 15 years old. Procedure Horses underwent laparotomy and occlusion of the lumen and vasculature of the mid-portion of the pelvic flexure of the large colon. During ischemia of 1 randomly-chosen colonic segment, variables were measured to determine colonic mucosal damage and were compared with histologic scores of colonic biopsy specimens. Results Significant (P < 0.05) differences from control values were observed over time for venous pH, Pco2, Po2, oxygen saturation, oxygen content, arteriovenous oxygen difference, and lactate and glucose concentrations. Mean histologic scores of biopsy specimens obtained from ischemic colons were significantly (P < 0.05) greater (indicating greater damage) than those from control colons, and increased significantly (P < 0.05) with duration of ischemia. Conclusions Venous lactate, oxygen saturation, and Po2 values were the most significant predictors of the severity of histologic damage within the ischemic colons (R2 = 0.661). Clinical Relevance Venous blood gas and lactate values in the large colon are good predictors of the amount of intestinal damage incurred during 3 hours of ischemia, and may be clinically useful for the rapid determination of colonic viability.