title: Hemoglobin Area and Time Index Above 90 g/L are Associated with Improved 6-Month Functional Outcomes in Patients with Severe Traumatic Brain Injury.
abstract: OBJECTIVE
  There is conflicting data on the relationship between anemia and outcomes in patients with traumatic brain injuries (TBI). The objective of this study was to determine if the proportion of time and area under the hemoglobin-time curve of ≥90 g/L are independently associated with 6-month functional outcomes.
  
  
  METHODS
  Retrospective cohort study of 116 patients with a severe TBI who underwent invasive neuromonitoring between June 2006 and December 2013. Hemoglobin area (HAI) and time (HTI) indices were calculated by dividing the total area, or time, under the hemoglobin-time curve at 90 g/L or above by the total duration of monitoring. Multivariable log-binomial regression was used to model the association between HAI or HTI and 6 month favorable neurologic outcome (Glasgow Outcome Score 4 or 5).
  
  
  RESULTS
  Patients had a mean age of 38 years (SD 16) with a median admission Glasgow Coma Scale of 6 (IQR 4-7). There were 1523 hemoglobin measurements and 523 monitoring days. Patients had a hemoglobin ≥90 g/L for a median of 70 % (IQR 37-100) of the time. Each 10 g/L increase in HAI (RR 1.23, 95 %CI 1.04-1.44, P = 0.011), and 10 % increase in HTI (1.10, 95 %CI 1.04-1.16, P < 0.001) were associated with improved neurologic outcome. Thirty-one patients (27 %) received a transfusion with the median pre-transfusion hemoglobin being 81 g/L (IQR 76-87).
  
  
  CONCLUSIONS
  In patients with severe TBI, increased area under the curve and percentage of time that the hemoglobin concentration was ≥90 g/L, were associated with improved neurologic outcomes.
authors.affiliation: Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia, Room 2438, Jim Pattison Pavilion, 2nd Floor, 855 West 12th Avenue, Vancouver, BC, V5Z 1M9, Canada, donald.griesdale@vch.ca.
authors.forename: Donald E
authors.initials: DE
authors.lastname: Griesdale
authors.forename: Mypinder S
authors.initials: MS
authors.lastname: Sekhon
authors.forename: David K
authors.initials: DK
authors.lastname: Menon
authors.forename: Andrea
authors.initials: A
authors.lastname: Lavinio
authors.forename: Joseph
authors.initials: J
authors.lastname: Donnelly
authors.forename: Chiara
authors.initials: C
authors.lastname: Robba
authors.forename: Indeep S
authors.initials: IS
authors.lastname: Sekhon
authors.forename: Andrew
authors.initials: A
authors.lastname: Taylor
authors.forename: William R
authors.initials: WR
authors.lastname: Henderson
authors.forename: Alexis F
authors.initials: AF
authors.lastname: Turgeon
authors.forename: Arun K
authors.initials: AK
authors.lastname: Gupta
mesh_terms: D000328:Adult; D001930:Brain Injuries / Q000097:blood* / Q000628:therapy; D005260:Female; D015600:Glasgow Coma Scale; D023261:Glasgow Outcome Scale; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies
chemical_list: D006454:Hemoglobins