title: Analysis of the association of fluid balance and short-term outcome in traumatic brain injury.
abstract: BACKGROUND
  A balance of fluid intake and output (fluid balance) influences outcomes of critical illness, but the level of such influence remains poorly understood for traumatic brain injury (TBI) and was quantitatively examined in this study.
  
  
  METHODS
  We conducted a retrospective cohort study of 351 moderate and severe TBI patients to associate the degree of fluid balance with clinical outcomes of TBI. Fluid balance and intracranial pressure (ICP) were continuously recorded for 7days on patients admitted to neurocritical care unit (NCCU). The short-term outcome was dichotomized into improvement and deterioration groups based on changes in Glasgow Coma Scale (GCS) measured between admission and 30days after admission. Fluid balance was calculated as: Fluid intake (mL) - fluid outputs (mL)/day×5 and used to group patients in tertiles to study its effect on TBI outcome.
  
  
  RESULTS
  Patients at the low (<637mL) and upper (>3673mL) tertiles of fluid balance were associated with poor outcomes. Those in the upper tertile also had a higher incidence of acute kidney injury (AKI) and refractory intracranial hypertension (RIH). There was a negative correlation between the cumulative fluid balance and the short-term outcome for patients in the low tertile and a positive correlation between the cumulative fluid balance and the short-term outcome in the upper fluid balance group. Levels of fluid balance were also associated with serum creatinine (Cr, r=0.451, P<0.0001) and days in NCCU (r=0.188, P=0.001). More patients in the upper tertile had ICP higher than 20mmHg (P=0.009). A fluid balance in the upper tertile is an independent predictor of poor 30-day clinical outcomes after the adjustment for confounding variables in a multivariable logistic regression model.
  
  
  CONCLUSIONS
  We found that fluid balance in low and upper tertiles were associated with poor short-term outcomes and ICP variations. Fluid balance in the upper tertile may be an independent predictor for poor 30-day outcome, primarily due to high AKI and RIH.
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China; Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute, Tianjin, China; Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin Municipal Government, Tianjin, China.
authors.forename: Zilong
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China; Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute, Tianjin, China; Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin Municipal Government, Tianjin, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China; Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute, Tianjin, China; Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin Municipal Government, Tianjin, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China; Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute, Tianjin, China; Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin Municipal Government, Tianjin, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China; Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute, Tianjin, China; Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin Municipal Government, Tianjin, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China; Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute, Tianjin, China; Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin Municipal Government, Tianjin, China.
authors.forename: Yingsheng
authors.initials: Y
authors.lastname: Wei
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China; Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute, Tianjin, China; Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin Municipal Government, Tianjin, China. Electronic address: jianningzhang@hotmail.com.
authors.forename: Jianning
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China; Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute, Tianjin, China; Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin Municipal Government, Tianjin, China. Electronic address: jianghope@gmail.com.
authors.forename: Rongcai
authors.initials: R
authors.lastname: Jiang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000070642:Brain Injuries, Traumatic / Q000503:physiopathology*; D015331:Cohort Studies; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D007427:Intracranial Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D012372:ROC Curve; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D014882:Water-Electrolyte Balance / Q000502:physiology*; D055815:Young Adult
keywords: Acute kidney injury; Fluid balance; Intracranial pressure monitoring; Refractory intracranial hypertension; Traumatic brain injury