2998 Anatomical injury severity, physiological shock, and the biological response to trauma

<h3>Aims and Objectives</h3> Increasing injury severity generally results in poorer clinical outcomes for trauma patients, however determining the ‘severity’ of an injury is complex. Better understanding of how anatomical and physiological drivers relate to patient outcomes would support Emergency Department (ED) clinicians in providing optimal care. This study aimed to investigate the relationship between injury severity and mortality/multiple organ dysfunction, the immediate underlying biological response to injury, and how this varies between direct tissue trauma (related to anatomical injury severity) and tissue ischaemia/cell death (related to shock). <h3>Method and Design</h3> Prospectively collected data and samples from 413 patients recruited to the ACIT-II study (REC approval: 07/Q0603/29) at the Royal London Hospital were used. Patients were eligible if they arrived in the ED within two hours of injury and met local criteria for trauma team activation. ISS was used to assess anatomical injury severity and base deficit (BD) as a marker of shock. Proteomics analysis for 4979 proteins was performed on blood samples taken at presentation to the ED. Multivariable logistic regression models used bidirectional stepwise search by AIC. Non-parametric tests were used to assess correlation and significance adjusted to control for false discovery rate. All statistical analysis was performed using R. <h3>Results and Conclusion</h3> Increasing ISS was associated with worse 24hr mortality (adj OR=1.03, CI=1.02-1.05, p=&lt;0.001), 28 day mortality (adj OR=1.05, CI=1.04-1.07, p=&lt;0.001), and development of Multiple Organ Dysfunction Syndrome (adj OR=1.07, CI=1.06-1.08, p=&lt;0.001). ISS and BD were significantly correlated (⍴ = 0.33, p = &lt;0.01). Most proteins showed significant correlation (p = &lt;0.01) with ISS (87%) and/or BD (83%). 673 proteins showed the strongest correlation with ISS (absolute ⍴ ≥0.5), all also correlating with BD. 292 proteins correlated with ISS but not BD and 82 proteins correlated with BD but not ISS. Building understanding of the biological functions of these proteins will support development of personalised trauma care.