MEASUREMENT OF INSULIN PULSATILITY BY SAMPLING DIRECTLY FROM THE PORTAL-VEIN - A SURGICAL MODEL FOR PLACEMENT OF LONG-TERM PREHEPATIC VASCULAR SAMPLING CATHETERS

A practical and repeatable method for measurement of pulsatile insulin release in the dog was developed by direct, chronic cannulation of th e portal vein cephalad to the pancreas and the entry point of the cran ial pancreaticoduodenal vein, with subsequent exteriorization of the s ampling catheter. Mixed breed male dogs of various body weights and ag es underwent midline laparotomy for exposure of the portal vein system . After exposure the portal vein was dissected free and cannulated thr ough a purse-string suture placed just caudad (approximately 1 cm) to the entry point of the cranial pancreaticoduodenal vein with a cuffed, medical grade, silastic catheter. The catheter was advanced craniad t o a point just distal to the level of the liver and secured in place v ia the purse-string suture and a single stay suture. The catheter was then passed through the dorsolateral abdominal wall and routed subcuta neously 60 a point between the shoulder blades. After catheter plug at tachment the catheter was tested for patency, flushed, heparin locked, then was secured to the subcutaneous tissue between the scapulas. The dorsal skin wound and abdominal incision were closed in a routine man ner, and the dogs recovered from anesthesia. Catheter patency and func tion in all dogs were maintained for periods up to 4 weeks. No postope rative complications such as catheter tract infections occurred, maint enance was minimal, and all dogs were afforded complete freedom of mov ement and activity throughout the study, with no requirement for cumbe rsome jackets or wraps.