Chronic implantation of nonocclusive catheters and flow probes in the splanchnic and hindlimb vasculature of the rabbit.

Flow probes and nonocclusive catheters were simultaneously implanted in the splanchnic and hindlimb vasculature to measure regional blood flows and arteriovenous differences of individual organs in the conscious rabbit. Pulsed Doppler flow probes were constructed by modifying the technique of Haywood et al., and nonocclusive catheters were designed and constructed from Silastic tubing (0.6- or 0.9-mm OD) and surgical velour. Laparotomy was performed on rabbits under anesthesia, and the renal, mesenteric, iliac, or hepatic artery and portal vein were isolated and instrumented with a flow probe. A nonocclusive catheter was then inserted into the respective vein. Instrumentation of the hepatic system required probes on the hepatic artery and portal vein, and nonocclusive catheters were placed into hepatic and portal veins. One week later, rabbits were reanesthetized and nonocclusive catheters were inserted into the cranial vena cava via the jugular vein and abdominal aorta to the level of the celiac axis. Probes and catheters were evaluated daily up to 30 days. Implants remained functional for an average of 3 weeks, permitting chronic measurement of velocity and blood variables in individual tissue beds of the conscious rabbit.