Iterative Design and Proof of Concept Prototypes – Emergency Safety Valve for Portable Hemodialysis System

Thesis (Master's)--University of Washington, 2022The purpose of this project is to design and develop an emergency safety valve prototype for the University of Washington Center for Dialysis Innovation (CDI). This valve needs to work in conjunction with already marketed central venous catheters and the CDI’s portable artificial kidney. When activated by a sudden tensile force, the emergency safety valve will undergo disconnection causing deployment of the crushing mechanism and thus, stop blood flow within the dialysis system. This thesis followed a product development process that the product meets the objectives for intended use. The project began with a kickoff meeting to solidify the device goals. Next, the planning phase included literature review on the dialysis process, blood access types and designs. Then, failure mode analysis was performed. The outcome of this phase was identification of the design inputs: Compatible with central venous catheters, external to the catheter placed in subclavian artery, connects to a standard luer lock, failure occurs from a tensile force, and activates from disconnection. The design of the valve went through an iterative process that included designing, testing and analyzing. Three designs were created: The plug mechanism, the crushing mechanism via pin, and the crushing mechanism via flat spring. The crushing mechanism via flat spring showed an achievable outcome of stopping water flow, which was observed during characterization testing of the disconnection force and a simulated use test. This prototype will be handed off to CDI for further development and integration into the portable artificial kidney system