Interleukin-6 (IL-6) – an Early Marker of Chest Trauma

Background and Objective: Although in recent years methods in emergency medicine have been remarkably improved, thoracic trauma remains associated with high mortality. To select adequate treatment in multitrauma patients, early diagnosis of lung contusion is of great importance. Upon hospital admission, however, even modern imaging techniques frequently fail to correctly estimate both severity and extent of chest trauma. Therefore, the aim of our study was to define laboratory markers indicating chest trauma almost immediately after accident. Patients and Methods: 107 trauma patients were enrolled in this prospective study. Blood samples were taken immediately at the site of accident, on hospital admission, after 30 and 60 min, and 2-hourly for an interval of 12 h, then daily. In addition to the biochemical analysis of 20 different substances, the following data were drawn and correlated to the laboratory results: Injury Severity Score (ISS), Polytrauma Score (PTS), Ulm score HTAPE (trauma pattern-specific: head, thorax, abdomen, pelvis, extremities; 0–3 degrees each), Multiple Organ Failure (MOF) score accordings to Goris et al, overall lethality, primary and secondary lethality. All trauma scores were subject to descriptive analysis. Our main analysis focuses on the thorax trauma score including variable selection by logistic regression as well as ROC analysis. Results: In nonsurvivors, overall trauma severity and head injury were remarkably higher (15.9%) than in survivors. Whereas there was a strong correlation between head injury and primary lethality (≤ 3 days), secondary lethality (> 3 days post trauma) was charged by thoracic trauma as well as by limb trauma. Of all mediators investigated, it was interleukin-6 (IL-6) that showed highest correlations (p < 0.0001) to the extent of chest trauma, especially during the first hour after hospital admission. Further correlations, yet clearly less pronounced, were found between IL-6 and PTS, between ISS, abdominal pelvic and limb trauma, but not to head injury. Our findings suggest that there is a correlation between endotoxin and 6-keto-prostaglandin F 1α and the severity of thoracic injury, too, but it is of lower statistical impact compared to IL-6. The practical value of both mediators, however, is limited because of the sophisticated and time-consuming laboratory analysis they demand. Conclusion: The study results suggest IL-6 to be an early marker for the extent of chest trauma.