Lactic acid, neuron-specific enolase, and blood-brain barrier index after a severe traumatic brain injury: a prospective study.

Objective: To explore the clinical significance of dynamic monitoring of cerebrospinal fluid (CSF) and serum Lactic acid（Lac), neuron-specific enolase (NSE), and the blood-brain barrier (BBB) index in evaluating the condition and prognosis after a severe traumatic brain injury (TBI).

Methods: A total of 52 severe TBI patients admitted to the Department of Neurosurgery within 24 hours after injury were dynamically monitored. CSF and serum samples were collected on the 1st, 3rd, and 7th day after a severe TBI to monitor the changes in Lac, NSE, and the BBB index. Intracranial pressure (ICP), Glasgow coma scale (GCS), and 6-month Glasgow outcome scale-extended (GOS-E) were tested. According to the results of GOS-E, the patients were divided into two groups (i.e. the poor prognosis group and good prognosis group). Statistical analysis was conducted to investigate the clinical significance of dynamic monitoring of CSF and serum Lac, NSE, and BBB index after a severe TBI.

Results: After a severe TBI, the levels of Lac, NSE, and BBB in CSF and serum were significantly higher than those in the normal range. Lac, NSE, and the BBB index did not correlate with ICP (except serum Lac) but had correlations with GCS and post-injury 6 months post-injury (except serum Lac). Moreover, the correlations between Lac, NSE, and BBB index were statistically significant (p < 0.05): CSF Lac and CSF NSE; CSF Lac and serum NSE; Lac and BBB index of CSF; Lac and BBB index of CSF; NSE and CSE of serum; CSF NSE and BBB index; and serum NSE and BBB index. Additionally, serum NSE is correlated with NSE in CSF (p < 0.05).

Conclusion: After a severe TBI, dynamic monitoring of CSF and serum Lac, NSE, and BBB index has the potential to assess the condition, predict the prognosis, and have clinical significance.