Glial Fibrillary Acidic Protein in Serum After Traumatic Brain Injury and Multiple Trauma

TLDR

The study investigated whether GFAP is released after traumatic brain injury, its association with injury severity and outcome, and whether it is released after multiple trauma without brain injury. Prospectively enrolled 114 patients with TBI (with or without additional trauma) or multiple trauma without TBI, measuring serum GFAP daily from admission through ICU stay and recording CT classification, ICP, CPP, MAP, and 3‑month GOS. GFAP levels were higher in more severe TBI, correlated with worse ICP, CPP, MAP, and GOS, were elevated in nonsurvivors, remained normal in multiple trauma without TBI, confirming that GFAP release reflects TBI severity and outcome but not non‑brain trauma.

Abstract

Background: This study aimed to determine whether glial fibrillary acidic protein (GFAP) is released after traumatic brain injury (TBI), whether GFAP is related to brain injury severity and outcome after TBI, and whether GFAP is released after multiple trauma without TBI. Methods: This prospective study enrolled 114 patients who had TBI with or without multiple trauma (n = 101) or multiple trauma without TBI (n = 13), as verified by computerized tomography. Daily GFAP measurement began at admission (<12 hours after trauma) and continued for the duration of intensive care (1–22 days). Documentation included categorization of computerized tomography according to Marshall classification, based on daily highest intracranial pressure (ICP), lowest cerebral perfusion pressure (CPP), lowest mean arterial pressure (MAP), and 3-month Glasgow Outcome Score (GOS). Results: The GFAP concentration was lower for diffuse injury 2 than for diffuse injury 4 (p < 0.0005) or nonevacuated mass lesions larger than than 25 mL (p < 0.005), lower for a ICP less than 25 mm Hg than for a ICP of 25 mm Hg or more, lower for a CPP of 60 mm Hg or more than for a CPP of 60 mm Hg or less, lower for a MAP of 60 mm Hg or more than for a MAP less than 60 mm Hg (all p < 0.0005), and lower for a GOS of 1 or 2 than for a GOS of 3, 4 (p < 0.05), or 5 (p < 0.0005). After TBI, GFAP was higher in nonsurvivors (n = 39) than in survivors (n = 62) (p < 0.005). After multiple trauma without TBI, GFAP remained normal. Conclusions: The findings showed that GFAP is released after TBI, that GFAP is related to brain injury severity and outcome after TBI, and that GFAP is not released after multiple trauma without brain injury.