Body-worn, non-invasive sensor for monitoring stroke volume, cardiac output and cardiovascular reserve

Hemorrhagic shock induced by traumatic injury is a leading cause of mortality on the battlefield and in civilian trauma settings. The first hour following injury can be critical to survival, requiring frequent assessment of vital signs and intravascular volume needs. Conventional vital signs, such as heart rate and blood pressure, are generally nonspecific and slow to change until acute blood loss volume nears 25--30% of total blood volume. The lack of specificity associated with these vital signs limits their usefulness in the early detection and monitoring of acute blood loss. In contrast, measurements of cardiac output (CO), stroke volume (SV) and a new parameter termed Cardiovascular Reserve Index (CRI), follow the progression of hemorrhage and response to intravenous fluid therapy. They are superior indicators of blood loss volume and fluid resuscitation needs. We will demonstrate the implementation of all three parameters on a small, noninvasive body-worn device that is wirelessly connected to a central monitoring system.