ABNORMALITIES IN OXYGENATION, COAGULATION, AND FIBRINOLYSIS IN COLONIC BLOOD OF HORSES WITH EXPERIMENTALLY-INDUCED STRANGULATION OBSTRUCTION

Objective-To measure arterial and venous blood gas, coagulation, and f ibrinolysis variables in blood from isolated segments of control and i schemic large colons for the purpose of identifying variables for rapi d, indirect assessment of colonic mucosal injury. Design-Variables wer e 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 laparoto my and occlusion of the lumen and vasculature of the mid-portion of th e pelvic flexure of the large colon. During ischemia of 1 randomly-cho sen colonic segment, variables were measured to determine colonic muco sal damage and were compared with histologic scores of colonic biopsy specimens. Results-Significant (P < 0.05) differences from control val ues were observed over time for venous pH. PCO2, PO2, oxygen saturatio n, oxygen content, arteriovenous oxygen difference, and lactate and gl ucose concentrations. Mean histologic scores of biopsy specimens obtai ned from ischemic colons were significantly (P < 0.05) greater (indica ting greater damage) than those from control colons, and increased sig nificantly (P < 0.05) with duration of ischemia. Conclusions-Venous la ctate, oxygen saturation, and PO2 values were the most significant pre dictors of the severity of histologic damage within the ischemic colon s (R(2) = 0.661). Clinical Relevance-Venous blood gas and lactate valu es in the large colon are good predictors of the amount of intestinal damage incurred during 3 hours of ischemia, and may be clinically usef ul for the rapid determination of colonic viability.