Evaluation of urine NGAL levels in brain death patients due to trauma: a prospective observational study

Abstract Background Brain death resulting from traumatic brain injury (TBI) can lead to significant changes in kidney function and morphology. Neutrophil gelatinase-associated lipocalin (NGAL) is a promising biomarker for early detection of acute kidney injury (AKI). This study aimed to evaluate urine NGAL levels in patients with brain death due to trauma and assess its relationship with kidney function and injury. Methods This prospective observational study included 63 patients diagnosed with brain death due to TBI. Urine NGAL levels were measured at 0, 12, 24, and 48 h after brain death diagnosis. Other parameters assessed included serum creatinine, glomerular filtration rate (GFR), and urine output. AKI was diagnosed on the basis of KDIGO 2012 criteria. Kidney biopsy was performed at 12 h, and histopathological damage was scored according to the Karpinski classification. Results Urine NGAL levels increased significantly over time after brain death ( p < 0.05). Urine NGAL levels were significantly higher in patients who developed AKI compared with those without AKI at 0 h and 12 h ( p < 0.001). At 0 h, urine NGAL had excellent predictive value for AKI with area under receiver operating characteristic (ROC) curve of 0.992 (95% CI 0.976–1.000, p < 0.001). At 12 h, urine NGAL maintained good predictive ability with AUC of 0.918 (95% CI 0.834–1.000, p < 0.001). Urine NGAL levels correlated positively with histopathological kidney damage scores at 12 h ( p < 0.001). Conclusions Urine NGAL levels increase significantly after brain death due to trauma and show excellent predictive value for AKI in these patients. Urine NGAL may serve as an early and sensitive biomarker of kidney injury in patients with brain death being considered as potential organ donors.