Patients

The current study enrolled 276 participants from January 2016 to December 2021 in The First People's Hospital of Wenling. All the participants were admitted in the present study's hospital within six hours after trauma with a Mean Arterial Pressure (MAP) < 60 mmHg. All the participants possessed detailed clinicopathological information including age, body weight, MAP, body temperature, respiratory rate, ISS score, peripheral inflammatory factor levels, and blood hemodynamics parameters. For those who: 1) Died within one hour after the admission; 2) Had a MAP higher or lower than the administration requirement for LFR; 3) Had hypertension; 4) Had brain traumas; 5) Had blood transfusion therapy or interventional treatment within one hour after the admission were excluded from the study. The shock was diagnosed based on the criteria published by the European Society of Intensive Care Medicine.¹⁰ The cohort included 189 males and 87 females, and 147 cases with scalp lacerations without intracranial injury, 19 cases with neck injuries, 36 cases with rib fractures with or without intrathoracic hemorrhage, 29 cases with abdominal injuries, 13 cases with pelvic fractures, 32 cases with long bone fractures with or without joint lesions. The study was approved by the ethics committee of The First People's Hospital of Wenling for the related screening, inspection, and data collection (KY-2023-2049-01). All the patients had signed a written informed consent form. All the experiment procedures were performed in accordance with the Declaration of Helsinki.