RESEARCHlactate to determine significant bleeding (defined as the presence of hemostatic surgery and the need for transfusion of blood components and/or death due to hypovolemic shock) whether due to clinical history, diagnostic imaging, or surgical procedure.This study had an institutional ethical endorsement from the HUSJ in Popayán, Cauca, Colombia, and followed national and international bioethical regulations for research.Since there is an institutional protocol to measure arterial gases in emergency trauma, the patient's informed consent was provided as an intervention, which is different from usual practice.Sociodemographic, clinical, and blood gas variables at admission, and results from 30 days of follow-up were included.The need for blood transfusions in the IntroductIonHemorrhagic shock (HS) is the leading cause of death in trauma patients.Several triage markers have been proposed to predetermine HS in patients.The first is the SI, which was described by Allgower and Burri in 1967 as the relationship between heart rate and systolic blood pressure. 1 The second is BD, recently adopted by the advanced trauma life support (ATLS) from its tenth edition in 2018. 2 The last marker is lactate, which has been studied in different shock scenarios. 3,4 Various trauma triage tools with adequate sensitivity allow for early identification of HS that would otherwise be overlooked due to compensatory mechanisms.The objective of this study was to compare SI, BD, and lactate in trauma settings to predetermine patient bleeding and predict blood component transfusion, vasopressor requirement, Intensive Care Unit (ICU) admission, surgery to control bleeding, and 30-day mortality. MethodsA prospective cohort was carried out between October 2019 and March 2020.This included patients (14 years and older) admitted to the Hospital Universitario San José (HUSJ in Spanish) Emergency Department for Trauma that required attention from the general surgery team.Patients excluded were those who received extrainstitutional surgical management, who were admitted to cardiorespiratory arrest, and those referred to other institutions.All included patients had complete vital signs taken on admission, which were used to calculate SI and arterial blood gases with 1-