title: Analysis of risk classification for massive transfusion in severe trauma using the gray zone approach.
abstract: BACKGROUND
  The Traumatic Bleeding Severity Score (TBSS) was developed to predict the need for massive transfusion (MT). The aim of this study is evaluation of clinical thresholds for activation of a MT protocol using the gray zone approach based on TBSS.
  
  
  METHODS
  This is a single-center retrospective study of trauma patients, admitted from 2010 to 2013. The TBSS on admission was calculated, and the accuracy of predicting MT was analyzed using area under the receiver operating characteristic curve. Risk classification for MT was made using sensitivity/specificity. The gray zone (indeterminate risk) was defined from a sensitivity of 95% to a specificity of 95%, patients were separated into MT and non-MT groups, and their clinical characteristics were compared.
  
  
  RESULTS
  A total of 264 patients were enrolled, with an area under the TBSS curve of 0.967 (95% confidence interval, 0.94-0.99). A TBSS of 10 points or less resulted in a sensitivity of 96.5% with 146 patients in this group, and 3.4% (5/146) of them received MT. A TBSS of 17 points or higher had a specificity of 97.8%, which included 72 patients, and 94.4% (68/72) of them received MT. Forty-six patients had a TBSS from 11 to 16 points (gray zone), and 26.1% (12/46) of them received MT. Comparing the MT group (12/46) and non-MT group (34/46), coagulopathy and extravasation on computed tomographic scan were more prevalent in the MT group.
  
  
  CONCLUSIONS
  The TBSS is highly accurate in predicting the need for MT, and a risk classification for needing MT was created based on TBSS.
authors.affiliation: Advanced Medical Emergency Department & Critical Care Center, Japan Red Cross Maebashi Hospital, Tochigi, Japan; Department of Emergency Medicine, Jichi Medical University, Tochigi, Japan. Electronic address: alongthelongestway2003@yahoo.co.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ogura
authors.affiliation: Advanced Medical Emergency Department & Critical Care Center, Japan Red Cross Maebashi Hospital, Tochigi, Japan. Electronic address: icuqq@maebashi.jrc.or.jp.
authors.forename: Minoru
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Department of Emergency Medicine, Jichi Medical University, Tochigi, Japan. Electronic address: yizawa@ms2.jichi.ac.jp.
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Izawa
authors.affiliation: Advanced Medical Emergency Department & Critical Care Center, Japan Red Cross Maebashi Hospital, Tochigi, Japan. Electronic address: mi-nakamura@maebashi.jrc.or.jp.
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Nakamura
authors.affiliation: Advanced Medical Emergency Department & Critical Care Center, Japan Red Cross Maebashi Hospital, Tochigi, Japan. Electronic address: fujiken_sanjo_4138@yahoo.co.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Fujizuka
authors.affiliation: Department of Surgery, Jichi Medical University, Tochigi, Japan. Electronic address: alefor@jichi.ac.jp.
authors.forename: Alan T
authors.initials: AT
authors.lastname: Lefor
mesh_terms: D001803:Blood Transfusion; D005260:Female; D006470:Hemorrhage / Q000628:therapy*; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D014947:Wounds and Injuries / Q000150:complications* / Q000628:therapy