title: Use of serum biomarkers to predict cerebral hypoxia after severe traumatic brain injury.
abstract: The management of severe traumatic brain injury (TBI) focuses on prevention and treatment of secondary insults such as cerebral hypoxia (CH). There are a number of biomarkers that are thought to play a part in secondary injury following severe TBI. This study evaluates the association between S100β, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP), detected in the serum of severe TBI patients and CH as measured by brain tissue oxygen partial pressure (Pbo(2)). Patients with severe TBI were prospectively enrolled. Pressure times time (PTD; mm Hg*h), measuring the depth and duration of CH, was calculated for 12-h periods for episodes of moderate (Pbo(2) < 20 mm Hg) and severe (Pbo(2) < 15 mm Hg) CH, and compared to serum levels of S100β, NSE, and GFAP drawn prior to periods of monitoring. An adjusted mixed model analysis was applied as was receiver operating characteristic (ROC) curve analysis. Of 76 patients enrolled, 24 had Pbo(2) monitoring. One hundred and thirty serum samples were matched with 12-h periods of monitoring. Significant associations were found in adjusted analyses between increasing serum levels of S100β (coefficient=0.57, 0.56; p<0.001), NSE (coefficient=0.48, 0.52; p<0.001), and GFAP (coefficient=0.29, 0.30; p=0.003 and 0.002), and increasing PTD of moderate (Pbo(2)<20 mm Hg) and severe (Pbo(2)<15 mm Hg) CH. AUCs for the prediction of moderate and severe CH were 0.62 and 0.66 for S100β, 0.55 and 0.71 for NSE, and 0.50 and 0.62 for GFAP, respectively. Specificities were between 76% and 90% for S100β and NSE. S100β, NSE, and GFAP demonstrate promise as candidate serum markers of impending CH. The fact that these biomarker elevations occur prior to the onset of clinical manifestations suggests that we may be able to predict imminent events following TBI. Given the morbidity of CH, early intervention and prevention may have a significant impact on outcomes and help guide decisions about the timing of interventions.
authors.affiliation: R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA. dstein@umm.edu
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Stein
authors.forename: Allison L
authors.initials: AL
authors.lastname: Lindell
authors.forename: Karen R
authors.initials: KR
authors.lastname: Murdock
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Kufera
authors.forename: Jay
authors.initials: J
authors.lastname: Menaker
authors.forename: Grant V
authors.initials: GV
authors.lastname: Bochicchio
authors.forename: Bizhan
authors.initials: B
authors.lastname: Aarabi
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Scalea
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001930:Brain Injuries / Q000097:blood* / Q000150:complications*; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000097:blood; D006801:Humans; D002534:Hypoxia, Brain / Q000097:blood* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009414:Nerve Growth Factors / Q000097:blood; D010751:Phosphopyruvate Hydratase / Q000097:blood; D012372:ROC Curve; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D010751:Phosphopyruvate Hydratase