title: Increasing hematocrit above 28% during early resuscitative phase is not associated with decreased mortality following severe traumatic brain injury.
abstract: BACKGROUND
  To prevent iatrogenic damage, transfusions of red blood cells should be avoided. For this, specific and reliable transfusion triggers must be defined. To date, the optimal hematocrit during the initial operating room (OR) phase is still unclear in patients with severe traumatic brain injury (TBI). We hypothesized that hematocrit values exceeding 28%, the local hematocrit target reached by the end of the initial OR phase, resulted in more complications, increased mortality, and impaired recovery compared to patients in whom hematocrit levels did not exceed 28%.
  
  
  METHODS
  Impact of hematocrit (independent variable) reached by the end of the OR phase on mortality and morbidity determined by the extended Glasgow outcome scale (eGOS; dependent variables) was investigated retrospectively in 139 TBI patients. In addition, multiple logistic regression analysis was performed to identify additional important variables.
  
  
  RESULTS
  Following severe TBI, mortality and morbidity were neither aggravated by hematocrit above 28% reached by the end of the OR phase nor worsened by the required transfusions. Upon multiple logistic regression analysis, eGOS was significantly influenced by the highest intracranial pressure and the lowest cerebral perfusion pressure values during the initial OR phase.
  
  
  CONCLUSIONS
  Based on this retrospective observational analysis, increasing hematocrit above 28% during the initial OR phase following severe TBI was not associated with improved or worsened outcome. This questions the need for aggressive transfusion management. Prospective analysis is required to determine the lowest acceptable hematocrit value during the OR phase which neither increases mortality nor impairs recovery. For this, a larger caseload and early monitoring of cerebral metabolism and oxygenation are indispensable.
authors.affiliation: Surgical Intensive Care Medicine, University Hospital Zürich, 8091 Zürich, Switzerland.
authors.forename: Carole
authors.initials: C
authors.lastname: Flückiger
authors.forename: Markus
authors.initials: M
authors.lastname: Béchir
authors.forename: Mirko
authors.initials: M
authors.lastname: Brenni
authors.forename: Silke
authors.initials: S
authors.lastname: Ludwig
authors.forename: Jutta
authors.initials: J
authors.lastname: Sommerfeld
authors.forename: Silvia R
authors.initials: SR
authors.lastname: Cottini
authors.forename: Marius
authors.initials: M
authors.lastname: Keel
authors.forename: Reto
authors.initials: R
authors.lastname: Stocker
authors.forename: John F
authors.initials: JF
authors.lastname: Stover
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D001921:Brain / Q000098:blood supply; D001930:Brain Injuries / Q000097:blood* / Q000401:mortality / Q000601:surgery*; D003399:Craniotomy; D003422:Critical Care; D017707:Erythrocyte Transfusion; D005260:Female; D015600:Glasgow Coma Scale; D023261:Glasgow Outcome Scale; D006400:Hematocrit; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D009104:Multiple Trauma / Q000097:blood / Q000401:mortality / Q000601:surgery; D010949:Plasma; D011183:Postoperative Complications / Q000097:blood / Q000209:etiology* / Q000401:mortality; D012151:Resuscitation; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed