About 10% of patients entering the Emergency Department (ED) are subjected to an evaluation of their hydration conditions (volemic status) with the aim of evaluating and eventually improving their vital organ perfusion. For this purpose, different non-invasive techniques, like the measurement of inferior vena cava (IVC) pulsatility, are commonly adopted to understand the volemic status of patients. Unfortunately, these techniques proved to have some limitations, for example varying respiratory pattern in spontaneous breathing can affect IVC ultrasound reliability. Even though new methodologies to evaluate the vital organ perfusion have been developed, some studies about Venous Pulse Wave Velocity (vPWV) are still performed.