ORIGINAL RESEARCH Open Access Therapeutic hypothermia in patients with coagulopathy following severe traumatic brain injury Toru Hifumi 1,6* , Yasuhiro Kuroda 1 , Kenya Kawakita 1 , Susumu Yamashita 2 , Yasutaka Oda 3 , Kenji Dohi 4 , Tsuyoshi Maekawa 5 and on behalf of the Brain Hypothermia (B-HYPO) study group in Japan Abstract Background: Coagulopathy in traumatic brain injury (TBI) has been associated with poor neurological outcomes and higher in-hospital mortality. In general principle of trauma management, hypothermia should be prevented as it directly worsens coagulopathy. Therefore, we examined the safety of mild therapeutic hypothermia (MTH) in patients with coagulopathy following severe TBI. Methods: We re-evaluated the brain hypothermia (B-HYPO) study data based on coagulopathy and compared the Glasgow Outcome Scale scores and survival rates at 6 months using per protocol analyses. Coagulopathy was defined as an activated partial thromboplastin time (APTT) > 60 s and/or fibrin/fibrinogen degradation product levels (FDP) > 90 μg/mL on admission. Baseline characteristics, coagulation parameters, and outcomes were compared between the control and MTH groups with or without coagulopathy. Results: In patients with coagulopathy, 12 patients were allocated to the control group (35.5–37.0 °C) and 20 patients to the MTH group (32–34 °C). In patients without coagulopathy, 28 were allocated to the control group and 59 patients were allocated to the MTH group. In patients with coagulopathy, favorable neurological outcomes and survival rates were comparable between the control and MTH groups (33.3% vs. 35.0%, P = 1.00; 50.0% vs. 60.0%, P = 0.72) with no difference in complication rates. On admission, no significant differences in APTT or FDP levels were observed between the two groups; however, APTT was significantly prolonged in the MTH group compared to the control group on day 3. Discussion: Based on our study, MTH did not seem to negatively affect the outcomes in patients with coagulopathy following severe TBI on admission; therefore, the present study indicates that MTH may be applicable even in patients with severe TBI and coagulopathy. Conclusions: Our study suggests that in comparison to control, MTH does not worsen the outcome of patients with coagulopathy following severe TBI. Trial registration: UMIN-CTR, No. C000000231, Registered 13 September 2005. Keywords: Coagulopathy, Therapeutic hypothermia, Traumatic brain injury, Targeted temperature management, Fibrinogen degradation products * Correspondence: hifumitoru@gmail.com 1 Department of Emergency, Disaster and Critical Care Medicine, Kagawa University Hospital, 1750-1 Ikenobe, Miki, Kita, Kagawa 761-0793, Japan 6 Department of Emergency, Disaster and Critical Care Medicine, 1750-1 Ikenobe, Miki, Kita, Kagawa 761-0793, Japan Full list of author information is available at the end of the article © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Hifumi et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine (2017) 25:120 DOI 10.1186/s13049-017-0465-y