Many medical conditions require health care providers to make rapid and accu- rate assessments of a patients hemodynamics to diagnose and guide treatment. Of the parameters that encompass hemodynamic evaluation (such as heart rate and blood pressure), one remains woefully measured: intravascular volume status. A measure of how much blood a subject has with which to perfuse oxygen, deliver nutrients, and remove wastes, volume status lays the foundation of many types of fluid based treatments for the acutely and critically ill in emergency rooms and in- tensive cares units to the chronically ill of cardiovascular and dialysis centers. Yet for all its physiological importance, many current assessments of volume status and responsiveness have a predictive power around the level of a coin flip. This work seeks to remedy this dire situation by improving a technique already utilized at the bedside (ultrasound measurement of inferior vena cava collapsibility) and introducing another that could be used through all echelons of care (impedimetric intravascular volume evaluation). Specifically, three major accomplishments were achieved: (1) an open-source software toolbox was developed to help clinicians and researchers rigorously evaluate vessel strain, stress, and wall shear; (2) a novel bioimpedance technique was demonstrated in several patient populations; and (3) a wearable electronic device was created to continuously measure a subject’s vol- ume status. Such a multimodal approach to hemodynamic monitoring serves the needs of both physicians and their patients across many clinical environments and ought to improve outcomes.
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