Characteristics of traumatic major haemorrhage in a tertiary trauma center
Authors: van Wyk Pieter , Wannberg Marcus , Gustafsson Anna , Yan Jane , Wikman Agneta , Riddez Louis , Wahlgren Carl-Magnus 
Published: March 2024

Abstract
Background
Major traumatic haemorrhage is potentially preventable with rapid haemorrhage control and improved resuscitation techniques. Although advances in prehospital trauma management, haemorrhage is still associated with high mortality. The aim of this study was to use a recent pragmatic transfusion-based definition of major bleeding to characterize patients at risk of major bleeding and associated outcomes in this cohort after trauma.

Methods
This was a retrospective cohort study including all trauma patients (n = 7020) admitted to a tertiary trauma center from January 2015 to June 2020. The major bleeding cohort (n = 145) was defined as transfusion of 4 units of any blood components (red blood cells, plasma, or platelets) within 2 h of injury. Univariate and multivariable logistic regression analyses were performed to identify risk factors for 24-hour and 30-day mortality post trauma admission.

Results
In the major bleeding cohort (n = 145; 145/7020, 2.1% of the trauma population), there were 77% men (n = 112) and 23% women (n = 33), median age 39 years [IQR 26–53] and median Injury Severity Score (ISS) was 22 [IQR 13–34]. Blunt trauma dominated over penetrating trauma (58% vs. 42%) where high-energy fall was the most common blunt mechanism and knife injury was the most common penetrating mechanism. The major bleeding cohort was younger (OR 0.99; 95% CI 0.98 to 0.998, P = 0.012), less female gender (OR 0.66; 95% CI 0.45 to 0.98, P = 0.04), and had more penetrating trauma (OR 4.54; 95% CI 3.24 to 6.36, P = 0.001) than the rest of the trauma cohort. A prehospital (OR 2.39; 95% CI 1.34 to 4.28; P = 0.003) and emergency department (ED) (OR 6.91; 95% CI 4.49 to 10.66, P = 0.001) systolic blood pressure < 90 mmHg was associated with the major bleeding cohort as well as ED blood gas base excess < -3 (OR 7.72; 95% CI 5.37 to 11.11; P < 0.001) and INR > 1.2 (OR 3.09; 95% CI 2.16 to 4.43; P = 0.001). Emergency damage control laparotomy was performed more frequently in the major bleeding cohort (21.4% [n = 31] vs. 1.5% [n = 106]; OR 3.90; 95% CI 2.50 to 6.08; P < 0.001). There was no difference in transportation time from alarm to hospital arrival between the major bleeding cohort and the rest of the trauma cohort (47 [IQR 38;59] vs. 49 [IQR 40;62] minutes; P = 0.17). However, the major bleeding cohort had a shorter time from ED to first emergency procedure (71.5 [IQR 10.0;129.0] vs. 109.00 [IQR 54.0; 259.0] minutes, P < 0.001). In the major bleeding cohort, patients with penetrating trauma, compared to blunt trauma, had a shorter alarm to hospital arrival time (44.0 [IQR 35.5;54.0] vs. 50.0 [IQR 41.5;61.0], P = 0.013). The 24-hour mortality in the major bleeding cohort was 6.9% (10/145). All fatalities were due to blunt trauma; 40% (4/10) high energy fall, 20% (2/10) motor vehicle accident, 10% (1/10) motorcycle accident, 10% (1/10) traffic pedestrian, 10% (1/10) traffic other, and 10% (1/10) struck/hit by blunt object. In the logistic regression model, prehospital cardiac arrest (OR 83.4; 95% CI 3.37 to 2063; P = 0.007) and transportation time (OR 0.95, 95% CI 0.91 to 0.99, P = 0.02) were associated with 24-hour mortality.

Results
Early identification of patients at high risk of major bleeding is challenging but essential for rapid definitive haemorrhage control. The major bleeding trauma cohort is a small part of the entire trauma population, and is characterized of being younger, male gender, higher ISS, and exposed to more penetrating trauma. Early identification of patients at high risk of major bleeding is challenging but essential for rapid definitive haemorrhage control.