Comparison of biochemical markers and transcranial Doppler ultrasonography findings as early predictors of outcome in patients with traumatic brain injury: preliminary report

Introduction

Early brain ischemia after traumatic brain injury (TBI) is predictive of pure outcome. We investigated the time course of biochemical markers of brain damage: serum neuron-specific enolase (NSE) and protein S-100 (Pr S-100) during the first 5 days after the ICU admission. Brain hemodynamics were synchronously assessed using transcranial Doppler ultrasonography (TCD). Each patient was examined with TCD, and the maximum, mean, and the end diastolic velocities and pulsatility index (PI) were evaluated.

Methods

Eleven patients (aged 34 ± 14.7, APACHE II score 15.7 ± 9, SAPS II 25 ± 13.7) with TBI were included in this prospective study. Paired arterial and jugular bulb blood concentrations of NSE and Pr S-100 were measured daily for five consecutive days and were correlated with neurological outcome evaluated by GOS score. TCD middle cerebral artery velocities and PI were also measured daily after admision and were correlated with biochemical markers and outcome at ICU discharge. The statistical analysis was performed using the Wilcoxon U test and Spearman correlation test.

Results

NSE and PrS-100 concentrations were significantly higher in patients with poor outcome (GOS 1–3) than in patients with good outcome (GOS 4–5) both in arterial as well as in jugular venous blood samples during the first 5 days. There were significant correlations between these biochemical indicies and the neurological outcome of patients from day 2 after admission (Pr S-100: r = 0.76, P = 0.02, NSE: r = 0.67, P = 0.03) that persisted for the following 3 days. TCD findings were not correlated neither with neurological outcome nor with biochemical markers of brain damage.

Conclusion

The biochemical markers of brain injury (NSE, Pr S = 100) seem to be better early outcome prediction parameters than cerebral blood flow velocities and PI measured by TCD in patients with TBI.