Endotoxemia associated with experimentally induced multiple portosystemic shunts in dogs

Abstract Objective To document presence of endotoxin in portal and systemic blood in a model of canine multiple portosystemic shunts (PSS), and compare values in clinically normal dogs, before and after vena caval banding. Animals 6 control dogs and 10 dogs with dimethylnitrosamine-induced multiple PSS that were subjected to vena caval banding. Procedure Dimethylnitrosamine was administered orally (2 mg/kg of body weight, twice weekly) to the 10 dogs in the diseased group until multiple PSS developed. Surgery was then performed on all 16 dogs (both groups), and shunts were confirmed in the diseased dogs. Blood was collected from the portal vein, hepatic vein, and caudal vena cava for baseline endotoxin determination and aerobic and anaerobic blood culturing. Baseline pressure measurements were taken from the portal venous catheter; then vena caval banding was performed. Blood for endotoxin determinations was taken from all vessels 20, 40, 60, 120, 240, and 360 minutes after banding; portal pressure measurements were taken at the same time as sample acquisition. Blood for culturing was taken from the portal and hepatic venous catheters at 120, 240, and 360 minutes after banding. Results Dogs in the diseased group had significantly greater overall presence of endotoxin in the portal vein (P ≤ 0.0002), hepatic vein (P ≤ 0.0001), and caudal vena cava (P ≤ 0.0004) than did control dogs. With respect to time, endotoxin presence was greater in the diseased group before banding (P ≤ 0.0002), and at 20 (P ≤ 0.0008), 40 (P ≤ 0.002), 60 (P ≤ 0.006), and 120 (P ≤ 0.01) minutes after banding. Conclusions Endotoxemia is more frequently present in catheterized dogs with dimethylnitrosamine-induced hepatic disease and multiple PSS, compared with clinically normal dogs. Additionally, portal pressure changes induced by vena caval banding did not affect endotoxemia. Clinical Relevance Endotoxemia may exist in dogs with hepatic disease and multiple PSS, and should be kept in mind when formulating treatment (particularly antimicrobial selection) for dogs with suspected endotoxemia. (Am J Vet Res 1997;58:83–88)