1) Research Hypothesis

1. Trauma -> Inflammation -> Severe inflammation -> Poor prognosis
2. If the degree of inflammation in the serum is precisely measurable, the prognosis of patients with trauma can be predicted. In addition, if inflammatory processes linked to serum mitochondrial DNA copy number (smtDNAcn) and delta neutrophil index (DNI) are demonstrated, early intervention to improve outcomes in patients with trauma and a poor prognosis may be possible.

2) Basis of Research Hypothesis

1. The Sequential Organ Failure Assessment (SOFA) score is currently used as a measurement tool to evaluate the severity and prognosis of critically ill patients. Recently, some studies reported that the DNI, an inflammatory index, is useful as a prognostic index. Although DNI is a simple prognostic index, further studies are necessary to investigate its usefulness as a reliable prognostic index for severely injured patients.

2. Therefore, this study aimed to:

   i. prospectively analyze the effectiveness of DNI by measuring the degree of inflammation in severely injured patients;

   ii. Measure serum mitochondrial DNA, which is suggested as a mechanism preceding DNI elevation, and identify the sequence of inflammatory steps leading to circulating mitochondrial DNA as a damage-associated molecular pattern (DAMP), DNI, neutrophils, and inflammatory cytokines; and

   iii. Establish the effectiveness of each indicator as a prognostic factor, construct a prediction model for poor prognosis, and prove the effectiveness of the final risk model.

1) Research Objectives

1. Quantitative measurement of serum mtDNA copy number (smtDNAcn), delta neutrophil index (DNI), and inflammatory cytokines [interleukin (IL) -1β/2/6/12, Interferon (IFN-ℽ), Tumor necrosis factor (TNF-α), IL-4/10)] over time
2. Analysis of correlation between smtDNAcn, DNI, and inflammatory cytokines (IL-1β/2/6/12, IFN-ℽ, TNF-α, IL-4/10) at initial presentation, on trauma days #1 and #2, and poor outcomes [multiorgan distress syndrome (MODS), mortality]
3. Construction and validation of a prognostic index using biological markers associated with inflammation (smtDNAcn, DNI, and inflammatory cytokines)

2) Contents of the Research Project

1. Measurement of biological indicators over time - Measurement of smtDNAcn, DNI, and inflammatory cytokines over time using polymerase chain reaction (PCR) and multiplex assay in patients classified as severely injured based on the injury severity score (ISS) (ISS ≥16).
2. Analysis of correlation between biologic markers and poor outcomes (MODS, mortality) - Identification of independent risk factors to predict poor outcomes such as MODS and mortality among inflammatory markers (serum mtDNA copy number, DNI, neutrophil count, and inflammatory cytokines) in this study.
3. Predictive Model Construction and Validation - Construction of a scoring system using inflammatory markers (smtDNAcn, DNI, neutrophils, and cytokines) and comparison with the SOFA score

3) Strategies and methods for the research project

1. A. Subjects: all trauma patients who visited Wonju Severance Christian hospital, regional trauma center.

2. Study period and patients recruitment

   i. 1st and 2nd year (until construction of prognostic scoring system): 200 patients (MODS:50, mortality: 50)

   ii. 3rd year (for validation): 100 patients (MODS: 30, mortality: 30)

3. Measurement of serum mtDNA copy number, DNI, and inflammatory cytokines

   i. Blood sampling: At the initial presentation and again on trauma days #1 and #2.

   ii. smtDNAcn, cytokines (IL-1β/2/6/12, IFN-ℽ, TNF-α, IL-4/10) by PCR, multiplex, and DNI using an automatic cell analyzer.

4. Analysis of correlation between biologic markers and poor outcomes (MODS, mortality)

   i. Statistical analysis of inflammatory markers such as smtDNAcn, cytokines (IL-1β/2/6/12, IFN-ℽ, TNF-α, IL-4/10) measured at the initial presentation, on trauma day #1, and #2 between severely injured patients with no poor outcomes and those with poor outcomes such as MODS and mortality risk.

5. Risk model construction using inflammatory markers to predict MODS and mortality risk

   i. Recruitment of 100 severely injured patients for validation on 3rd year during study period

   ii. The recruited patients were divided into low-risk and high-risk groups according to the new risk model, cut-off value of each inflammatory marker, and SOFA score.

   iii. Comparison of sensitivity and specificity of the new risk model, inflammatory markers, and SOFA score.

Inclusion Criteria:

• Injury severity score ≥ 16

Exclusion Criteria:

• Age ≤18 years
• Pregnancy in women
• Death at initial presentation of the case
• Patients who refused to participate in the study

All severely injured patients with injury severiry score ≥ 16 older than 19 years of age who visited Wonju Severance Christian Hospital, regional trauma center will be included in the study