A-27 Free Communication/Poster - Military: JUNE 2, 2010 7:30 AM - 12:30 PM: ROOM: Hall C
Acute hemorrhage and subsequent circulatory collapse (shock) account for approximately 50% of the deaths on the battlefield and the forward operating table, a statistic that has remained relatively unchanged since World War I. Hemorrhage is defined as the escape of blood from a vessel and is the most common cause of hypovolemic shock. Current and classic techniques available to battlefield medics for triage and are focused on the traditional vital sign markers. Similarly, monitoring shock in the civilian trauma patient has also focused on the clinical "gold standard" assessments of Blood Pressure (BP), arterial O2 saturation or simple pulse palpation. However, these standard vital sign measurements fail to predict death or identify reductions in central blood volume until cardiovascular collapse has already occurred. About 10 percent of the total blood volume can be removed with almost no effect on either arterial pressure or cardiac output.
PURPOSE: To develop and demonstrate a system that rapidly and non-invasively tracks vital sign markers throughout the progression of hemorrhage.
METHODS: Orbital Research Inc (ORI) and Kent State University (KSU) used an incremental lower body negative pressure (LBNP) routine to safely educe physiologic changes like those typical to hemorrhage. Six research subjects have completed the study. An instrumented glove (developed by Orbital Research) collected vital signs intermittently and non-invasively during the experiment. Standards measure of metabolism; ECG and cardiac output were collected continuously.
RESULTS: Using the instrumented glove to collect cardiovascular metrics, differences in R-R interval variability and Lf/Hf ratio are were detected during the LBNP sequence. Cardiac output, stroke volume and blood pressure data verified the physiologic compensations in response to the LBNP.
CONCLUSIONS: Heart Rate Variability (HRV) has also shown promise and correlation to early reductions in central blood volume when blood pressures and SpO2 have not yet changed. This project demonstrated feasibility of using instrumented to glove to rapidly collect cardiovascular markers indicative of the onset of hemorrhage.