P1B-3 Noninvasive Bleeding Detection and Localization Using Three Dimensional Doppler Ultrasound

Blood loss from extremity wounds is the number one cause of preventable battlefield death today. In civilian casualties, exsanguinations due to internal bleeding are the most significant cause of death in trauma victims. The goal of DARPA's deep bleeder acoustic coagulation (DBAC) program is to stop bleeding quickly enough to prevent the transition from nonprogressive shock to progressive shock, which occurs when the soldier loses 25% of the blood volume. Coagulative therapies such as HIFU and electrocautery can be used to quickly stop internal bleeding to prevent onset of progressive and irreversible hemorrhagic shock, which ultimately leads to death. However, the onset of bleeding must be detected and the site spatially localized in order to treat these trauma wounds effectively. Towards meeting the final goal of the DBAC program, we have performed preliminary studies on in vitro tissue mimicking phantoms to identify unique Doppler based signatures that are indicative of bleeding. In this study, we present the results and validation of a 3D Doppler ultrasound technique to detect and localize the bleeding site by tracking the change in resistance index (RI) at the bleed origin. Significant RI change was obtained at the intersection of the primary vessel (feeding the bleeder) and the bleeding site (jet). Pulsatile flow with near zero diastolic flow was present in the primary vessel and the non-bleeding branches. Within the bleeding jet, continued or elevated forward flow was present during diastole resulting in reduction of RI. The estimated bleed location showed excellent agreement with independent ground truth estimates. The results illustrate potential for the applicability of the technique in battlefield trauma and civilian emergency care applications.