Neutrophil gelatinase-associated lipocalin as an early marker of acute kidney injury in patients with traumatic brain injury.

BACKGROUND: Recent studies have shown that urinary neutrophil gelatinase-associated lipocalin (NGAL) is rapidly up-regulated early after murine renal injury, and in patients after cardiac surgery or patients critically ill with multiple trauma. In this study, we evaluated urinary NGAL levels as a potential biomarker of early acute kidney injury (AKI) in patients with severe traumatic brain injury (TBI). METHODS: All patients with severe TBI admitted to our neurosurgical intensive care unit from March to September 2011 were enrolled prospectively. Urinary NGAL was measured using a chemiluminescent microparticle immunoassay upon admission and at 24 and 48 hours after TBI. The presence of AKI was defined by the Acute Kidney Injury Network (AKIN) criteria. RESULTS: Using AKIN criteria, a total of 13 patients were identified with AKI, an incidence of 24%. Those who subsequently developed AKI had a striking rise in urinary NGAL early after TBI and a sustained increase over the entire duration of the study. The urinary NGAL level of the AKI group was significantly higher than the group without AKI at all time points. Using a cutoff value of 53.9 ng/mL, the area under the receiver-operating characteristic curve for urinary NGAL at 48 hours was 0.876 with a sensitivity of 0.69 and specificity of 0.95. CONCLUSIONS: Increased urinary NGAL is associated with an increased occurrence of AKI in patients with severe TBI. It is possible that urinary NGAL could provide a screening tool for AKI immediately after severe TBI, and this may in turn allow early intervention to ameliorate the adverse effects of AKI.

Effects of mild hypothermia on patients with lower intracranial pressure following severe brain injury.

OBJECTIVE: To study the effects of mild hypothermia therapy on severe brain-injured patients whose intracranial pressure (ICP) could be maintained below 25 mm Hg. METHODS: Forty severe brain-injured patients with ICP below 25 mm Hg were divided randomly into one treatment group (n=20, mild hypothermia therapy) and one control group (n=20, normothermia therapy) to observe the changes of the concentration of excitatory amino acids (glutamate and glycine) and cytokines (interleukin-1beta and interleukin-6). RESULTS: There were no significant differences in the daily changes of the concentration of excitatory amino acid and cytokines between two groups. The outcome of two groups had no significant differences. CONCLUSIONS: Mild hypothermia has no additional beneficial effects on severe brain-injured patients compared with normothermia therapy if ICP can be maintained below 25 mm Hg by using conventional therapy.