AUTOMATED ANALYSIS OF VITAL SIGNS TO IDENTIFY PATIENTS WITH SUBSTANTIAL BLEEDING BEFORE HOSPITAL ARRIVAL: A FEASIBILITY STUDY

ABSTRACT—Trauma outcomes are improved by protocols for substantial bleeding, typically activated after physician evaluation at a hospital. Previous analysis suggested that prehospital vital signs contained patterns indicating the presence or absence of substantial bleeding. In an observational study of adults (aged Q18 years) transported to level I trauma centers by helicopter, we investigated the diagnostic performance of the Automated Processing of the Physiological Reg-istry for Assessment of Injury Severity (APPRAISE) system, a computational platform for real-time analysis of vital signs, for identification of substantial bleeding in trauma patients with explicitly hemorrhagic injuries. We studied 209 subjects pro-spectively and 646 retrospectively. In our multivariate analysis, prospective performance was not significantly different from retrospective. The APPRAISE system was 76 % sensitive for 24-h packed red blood cells of 9 or more units (95 % confi-dence interval, 59 % Y 89%) and significantly more sensitive (P G 0.05) than any prehospital Shock Index of 1.4 or higher; sensitivity, 59%; initial systolic blood pressure (SBP) less than 110 mmHg, 50%; and any prehospital SBP less than 9