A device, method and system are provided which simplify the self-administered peritoneal dialysis solution exchange procedure performed by a patient receiving continuous ambulatory peritoneal dialysis. The tool is preferably constructed of a material that is harder than the substrate so that a depression can be readily made therein. 9% by weight derivatives of sterically hindered amines selected from the group consisting of: soluble polymers or copolymers prepared by radical polymerization in the presence of 0. The occluder is mounted proximal to the port of the catheter, and the constrictor is mounted distal to the port. Constraint checking and cost estimation checking are performed for each message type.