Fabrication strategy and validation of phantoms for eco-guided femoral access

Vascular access is a usual practice in hospitals because it allows access to the vascular system to control parameters, drug administration, and treatment of various pathologies. In particular, the femoral arteries are the most commonly accessed vessels in complex situations that require direct access to the arterial circulation. However, this practice, can be challenging using classic methods of anatomical landmark palpation, as it can lead to complications such as arterial occlusion, pseudo-aneurysms and severe hemorrhages. For this reason, the use of Ultrasound (US) imaging techniques has become a common practice for vascular access over the years and requires training before operating directly on the patient. In the state-of-art, we find different types of simulators to train physicians with US technology but, each one has limitations regarding the simulation of the task. These include the lack of haptic feedback in the arterial puncture and the absence of fluid flow within the vessels. Also, they have high costs, unrealistic images and evident puncture marks on the material used which leads to reduced durability over time. This thesis aims to overcome the limitations of commercial phantoms, creating a US-compatible phantoms using a combination of materials that can replicate the arterial puncture task both mechanically and in US-imaging visualization. To achieve this goal, the idea was to use a plastic material such as PVC plastisol (PVC-P) for surrounding soft tissues thanks to its self-healing property, its speed of sound (SOS) in a medium similar to soft tissues, and the possibility of inserting additives, making it a durable phantom with easily modifiable physical properties; while polytetrafluoroethylene (PTFE) was chosen as a material for arterial coating, thanks to its appropriate rigidity and SOS. An in-depth analysis is reported to explain the choice of PVC-P and Teflon as main materials. To replicate the anatomy, a patient-specific mold was created from a CT scan and, an alignment system for the vessels was designed. Also, this system made it possible to integrate a pump to simulate water flow through the vessels. This fabrication strategy enables the production of reproducible phantoms that introduce innovations absent in commercial simulators, using low cost materials and an efficient preparation process. A "Face and Content validity" was carried out through tests with 8 experienced surgeons who evaluated the realism and utility of this simulator in a vascular surgery setting. The proposed simulator has the potential to gainfully be used as learning and training tool for new operators approaching this discipline.