Blood treatment catheter and method

#This invention relates in general to blood treatment catheters and more particularly to a design for use in hemo-dialysis in which the occlusion of the distal ports due to fibrin buildup is substantially eliminated.

#Hemo-dialysis is the process of mass transfer, in which certain chemical substances, accumulated in the blood because of kidney failure, are transferred from the blood across a semi permeable dialysis membrane to a balanced salt solution. The efficiency of a hemo-dialysis procedure depends on the amount of blood brought into contact with the dialysis membrane. A flow of 250 milliliters of blood per minute under a pressure gradient of 100 millimeters of mercury is considered a minimum requirement for adequate dialysis. Over the past several years, flow rate between 350 milliliters per minute and 400 milliliters per minute have become common.

#At the place where the catheter is inserted into the patient, the body reacts by creating a sheath of material that includes fibrin and other materials that grow down the outer wall of the catheter from the point of insertion in the vein. This material is referred to herein as occlusive material. This occlusive material when it grows down to the site of ports, and most particularly the aspirating port, tends to block the ports rendering the catheter essentially useless.

#FIG. 1 is a schematic illustration of the positioning of the hemo-dialysis catheter of this invention through the jugular vein. In FIG. 1, the catheter is inserted into the patient at point A and into the vein at point B.

#FIG. 2 is an elevation view of a catheter of this invention showing the infusion tube 18 and aspirating tube 20 combined at juncture 22 to form the main portion 24 of the catheter. Infusion ports 26 are at the distal end of the infusion lumen. Aspirating port 34 is at the distal end of the aspirating tube 20.

#FIG. 3 is a larger scale elevation view of the zone around the distal infusion port of an embodiment of the FIG. 2 catheter having a plurality of angled infusion ports 26a.

#The catheter 10 of this invention has an infusion lumen 11 and an aspirating lumen 12. The distal end 16 of the aspirating lumen extends distally beyond the distal end 14 of the infusion lumen 11.

#More particularly with respect to FIGS. 1 and 2, a standard infusion tube 18 and aspirating tube 20 are combined at a juncture 22 to provide a single tube 24 distal of the juncture 22. The tube 24 contains infusion and aspirating lumens. The tube 24 is inserted into a patient at point A and passed into the jugular vein 25 at point B to be positioned at a desired location; often in the right atrium 38 as shown in FIG. 10.

#FIGS. 3 and 4 illustrate a presently preferred embodiment of this invention in which the infusion port set 26 is constituted by ten ports 26a each having a major axis at an angle of approximately 45° to a circumferential line through the ports 26a. In this embodiment, each of the ports is approximately 50 mils (0.050 inches) by 20 mils (0.020 inches). These ports 26a are at the distal end of the infusion lumen 11.