Design and Development of a Prototype of a Catheter for Thoracentesis

Abstract

While thoracentesis and diagnostic and therapeutic drainage of pleural effusions have been performed routinely, catheter systems in use today do not provide much more than blocking off the area of catheter placement with limited reliable samples, introducing air into the pleural space and uncontrolled conditions when the catheter is inserted. Therefore, this Capstone project was designed to develop a prototype thoracentesis catheter that is safe for use, easy to operate, and provides superior functionality to existing catheters. Literature-based requirement definition, CAD concept implementation, material choice, additive-manufacturing-based prototyping, tensile testing, finite element analysis, and fluid-flow simulation were used to implement the project. SolidWorks was used to develop three design iterations, one being a single-lumen concept and two modified to have a flushing capability. Flexible 80A resin was selected as the initial prototype resin to SLA print and BioMed Flex 80A and AISI 316L were suggested as the possible material to develop into clinical grade. The catheter print was tested in two orientations and it was discovered that there was a trade-off between the quantity volume of resin applied and the quality of the print. Tensile testing with ASTM D412 Die-C specimen revealed that the time elapsed after the curing process had a significant impact on the mechanical response and the ultimate tensile strength mean was maximum at 15 min of the curing process. Simulation was conducted by use of finite elements to demonstrate that the most mechanically sensitive region of the distal perforated region during insertion and removal had von Mises stress of maximum 1.22 MPa and 0.606 MPa respectively. The simulations of the fluid revealed that the lumen was functional in real-life manual aspiration and in hypothetical maximum suction conditions. On the whole, the project confirmed the technical feasibility of the recommended concept of the catheter on the prototype level and established an engineering platform to further optimization, validation, and development of the catheter to a more clinically developed thoracentesis device.