Project Summary Vascular access is the most common medical procedure in the world, with over a billion insertions performed annually. In the United States, over 350-million peripheral intravenous (IV) catheters are sold yearly, in addition to millions of central and arterial lines. However, peripheral IV placement often requires several attempts at insertion, which is painful and time consuming. Furthermore, there is a high rate of early failure that can lead to further complications, including extravasation, thrombophlebitis, and compartment syndrome, as well as delays in delivery of therapeutic medications. Ultrasound guided vascular access is widespread and has advanced difficult IV access success rates, but there is clearly room for improvement as the success rate for ultrasound guided peripheral IV placement is stagnant at 80%. Improving the success rate for vascular access will have a huge impact on patient care and patient safety. To address the clinical need described above and overcome the current technical challenges, we have pioneered a novel concept of ‘active acoustic communication’ between needle and imaging systems for guidance. We are further evolving the concept into a clinical prototype that is intuitive and easy to use, low cost, disposable, works with any ultrasound vendor, offers easy needle tip tracking, and differentiates between tissue types. A ‘5T (tool tip tracking + tissue typing)-IV’ guidance platform will offer an integrated interface layer for clinicians, providing (1) high-spatiotemporal resolution (sub-millimeter and sub-second) tool tip tracking over a wide field-of-view, (2) encoded contrast with a flashing active echo pulse to visualize the needle tip, and (3) highly accurate tissue typing at the needle tip with (4) an unaltered clinical workflow. In this project, we will first develop a vendor-independent clinical prototype hardware and software package with comprehensive performance characterizations in tissue-mimicking phantoms, and this will guide further iteration of the form- factor and software user interface included in the clinical prototype to be tested in animals. The efficacy and user experience will be extensively evaluated in preclinical phantom models by performing human factor studies with 65 end users. Quantifiable metrics (e.g., success rate, time duration and number of trials) will be compared between conventional US and the 5T-IV guidance methods will be expanded to swine animal models for both jugular and femoral cannulation with different experience level (residents vs. attending anesthesiologists).