title: Precordial vibrations provide noninvasive detection of early-stage hemorrhage.
abstract: Graded lower-body negative pressure was used to create a hemodynamic response similar to hemorrhage. Echocardiogram measurements showed a maximal reduction of 32.4% in stroke volume. Analysis of systolic time intervals, such as pre-ejection period and left ventricular ejection time (LVET), derived from a seismocardiogram (SCG), were demonstrated to be more sensitive in detection of early-stage hemorrhage compared with pulse pressure, heart rate, and the amplitude features extracted from SCG. In particular, the LVET and pre-ejection period/LVET features, extracted from SCG, were significantly different between, and correlated with, the different stages of lower-body negative pressure (r = 0.9 and 0.88, P < 0.05), for 32 subjects. These results suggest a portable, cost-effective solution for identification of mild or moderate hemorrhage using accelerometers.
authors.affiliation: *Department of Electrical and Computer Engineering, University of British Columbia; and †Heart Force Medical Inc, Vancouver; and ‡Aerospace Physiology Laboratory, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Kouhyar
authors.initials: K
authors.lastname: Tavakolian
authors.forename: Guy A
authors.initials: GA
authors.lastname: Dumont
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Houlton
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Blaber
mesh_terms: D061725:Accelerometry / Q000295:instrumentation* / Q000379:methods*; D000328:Adult; D001794:Blood Pressure; D015150:Echocardiography, Doppler; D005260:Female; D006339:Heart Rate; D006470:Hemorrhage / Q000175:diagnosis*; D006801:Humans; D008150:Lower Body Negative Pressure; D008297:Male; D013318:Stroke Volume; D016277:Ventricular Function, Left / Q000502:physiology