Thrombus formation on catheters in new born lambs.

Catheters were inserted into the aorta and inferior vena cava of newborn lambs by cutdown on the femoral vessels and directly into the umbilical vein. The lambs were killed after six days and the amounts of thrombus surrounding the cathethers were measured. Most catheters inserted into the umbilical vein looped within the liver and only a few passed directly into the portal vein or through the ductus venosus into the vena cava. On different types of catheters inserted via the femoral artery or femoral vein, there were significant differences both in the proportion with thrombus and the amount of thrombus. There were also significant differences in renal infarctions caused by different types of catheters.