Improved longevity and functionality of a canine model providing portal vein and multi-site intestinal access

Background and Purpose: The canine intestinal and venous access port (IVAP) model is valuable for investigating hepatic elimination and region-specifi c intestinal absorption of pharmaceuticals. Previously, long-term functiona lity of this preparation has been variable. Methods: Catheters of different construction were placed in the proximal an d distal portions of the small intestine, colon, and portal vein of subject animals and were attached to separate subcutaneous access ports. Intraoper ative, postoperative, and long-term maintenance techniques were developed, modified, and analyzed. Results: Intestinal catheter infections and access site failures were assoc iated with breakdown at the intestinal insertion site, The ileal catheter w as prone to obstruction with ingesta. A modified Witzel technique, speciali zed port-catheter systems, scheduled port-flushing methods, and venous port infection treatment protocols improved the model's longevity. Conclusions: The canine IVAP model is a powerful tool for investigation of regional differences in intestinal absorption and hepatic elimination of dr ugs, Other researchers can derive increased longevity with the IVAP model b y using the technical modifications detailed here: strict sterile technique , closed-end slit-valve catheters, GPV(R) ports, the Witzel tunnel techniqu e, routine portal vein infection surveillance, 50% dextrose intestinal cath eter infusion, rapid removal of infected intestinal catheters, and critical appraisal of their results. Longevity of the model continues to be improve d.