(576) Cerebral Net Water Uptake Correlates With Brain Oxygen Status in Moderate TBI Patients

Introduction: One of the cornerstones of traumatic brain injury (TBI) therapy is maintaining adequate brain oxygen status. However, the relationship between cerebral oxygen status and cerebral hydration due to cerebral edema remains poorly understood. The aim was to study the relationship between net water uptake (NWU) and cerebral oxygen status in moderate TBI patients.

Methods: Cerebral computed tomography and cerebral oxygen status using NIRS were simultaneously performed for 35 patients with a moderate TBI at the Nizhny Novgorod Regional Trauma Center in 2013-2022. The mean age of the patients with head injury was 32.7 ± 12.5 years (from 18 to 65 years). They were 14 women and 21 men. The wakefulness level according to GCS (Glasgow Coma Score) averaged 10.7 ± 18.2 (from 9 to 12) before the study. The cerebral oximetry was performed using Fore-Sight 2030 (Casmed, USA) and included the detection of the SctO2 level in the region of the frontal lobe. Net water uptake was calculated from non-contrast computed tomography. Data are shown as a median [interquartile range]. P< 0.05 was considered statistically significant.

Results: The oxygen status in the frontal lobe tissue varied within the range from 51% to 88%. It was 62 ± 5.4% over the left frontal lobe and 60 ± 5.3% over the right frontal lobe. Values below the ischemic threshold (SctO2 less than 60%) were detected in 5 patients. It proved the ischemia development in the anterior cerebral artery vascularization area. Cerebral NWU values and the brain saturation level in the frontal lobes were pairwise compared. In the case when there were no focal injuries in the frontal lobes, NWU was significantly correlated with higher net water uptake (R = 0,431, p< 0.05). There were no significant correlations between the levels of cerebral oxygen status in the frontal lobe and NWU in another cerebral lobe.

Conclusions: The cerebral oxygen status correlates with net water uptake in patients with moderate TBI (p < 0.005). Cerebral NIRS can be used as a screening method for an indirect noninvasive assessment of the regional cerebral hydration level in patients with a moderate head injury.