• K Horst, R Pfeifer, M Teuben, D Eschbach, S Ruchholtz, M Frink, H-C Pape, and F Hildebrand.
• 1Department of Orthopedic Trauma and Harald Tscherne Research Laboratory, University Hospital Aachen 2Department of Trauma, Hand and Reconstructive Surgery, University of Giessen and Marburg, Germany.
• Shock. 2015 Oct 1;44 Suppl 2:22.

IntroductionThe purpose of this study was to investigate fracture-associated local inflammation in regard to therapeutic hypothermia and gain information about the early inflammatory stages after polytrauma.MethodsMale pigs were used. A standardized lung contusion was combined with a tibia fracture, liver laceration and controlled hemorrhage for 90 minutes. Following trauma, hypothermia of 33°C was induced in 15 animals (HT-T) and 5 sham animals (HT-S) for 12 h. The second group remained normothermic (NT-T, n = 15 resp. NT-S, n = 5). Intensive care treatment was evaluated for 48 h before animals were euthanized. Systemic blood samples, as well as samples from fracture hematoma were taken consistently. Cytokines IL-6, IL-8 and IL-10, as well as Alarmins HMGB1 and HSP70 were tested using ELISA kits.ResultsIn both groups, an increase of systemic pro-inflammatory mediators was observed over time when compared to baseline and sham (IL-6: NT p < 0.001 resp. HT p = 0.004). Moreover, concentrations of pro-inflammatory mediators were significant elevated in fracture hematoma compared to systemic levels (IL-6 at 14 h: NT p = 0.002; HT p = 0.001). In both groups, pro-inflammatory concentrations decreased over time while those in NT-T decreased significantly faster than in HT-T (IL-6 14 h vs. 48 h: NT p = 0.028 vs. HT p = 0.064; HMGB1: NT p = 0.047 vs. HT p = 0.239). Anti-inflammatory mediators only increased in the HT-T group (HT-T 0 h vs. 48 h: p = 0.020; HT-S: p = 0.009).ConclusionInduced hypothermia seems to influence the early immunologic milieu of fracture hematoma in regard to a prolonged pro-inflammatory and decreased anti-inflammatory state. These changes might influence induction of early bone healing.

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