ENDOTOXEMIA ASSOCIATED WITH EXPERIMENTALLY-INDUCED MULTIPLE PORTOSYSTEMIC SHUNTS IN DOGS

Objective-To document presence of endotoxin in portal and systemic blo od in a model of canine multiple portosystemic shunts (PSS), and compa re values in clinically normal dogs, before and after vena caval bandi ng. Animals-6 control dogs and 10 dogs with dimethylnitrosamine-induce d multiple PSS that were subjected to Vena caval banding. Procedure-Di methylnitrosamine was administered orally (2 mg/kg of body weight, twi ce weekly) to the 10 dogs in the diseased group until multiple PSS dev eloped. Surgery was then performed on all 16 dogs (both groups), and s hunts were confirmed in the diseased dogs. Blood was collected from th e portal vein, hepatic vein, and caudal vena cava for baseline endotox in determination and aerobic and anaerobic blood culturing. Baseline p ressure measurements were taken from the portal Venous catheter; then vena caval banding was performed. Blood for endotoxin determinations w as taken from all vessels 20, 40, 60, 220, 240, and 360 minutes after banding; portal pressure measurements were taken at the same time as s ample acquisition. Blood for culturing was taken from the portal and h epatic venous catheters at 120, 240, and 360 minutes after banding. Re sults-Dogs in the diseased group had significantly greater overall pre sence of endotoxin in the portal vein (P less than or equal to 0.0002) , hepatic vein (P less than or equal to 0.0001), and caudal vena cava (P less than or equal to 0.0004) than did control dogs. With respect t o time, endotoxin presence was greater in the diseased group before ba nding (P less than or equal to 0.0002), and at 20 (P less than or equa l to 0.0008), 40 (P less than or equal to 0.002), 60 (P less than or e qual to 0.006), and 120 (P less than or equal to 0.01) minutes after b anding. Conclusions-Endotoxemia is more frequently present in catheter ized dogs with dimethylnitrosamine-induced hepatic disease and multipl e PSS, compared with clinically normal dogs. Additionally, portal pres sure 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 treatme nt (particularly antimicrobial selection) for dogs with suspected endo toxemia.