Focal cerebral oxygenation and neurological outcome with or without brain tissue oxygen-guided therapy in patients with traumatic brain injury.

BACKGROUND: In patients with severe traumatic brain injury (TBI), the depth and duration of cerebral hypoxia are independent predictors of outcome. This study aimed to evaluate the efficacy of brain oxygen-guided therapy in improving cerebral oxygenation and neurological outcome in severe TBI patients.
METHODS: Thirty TBI patients had brain oxygen monitors placed contralateral to the side of mass lesions, or to the non-dominant side if injury was diffuse. The first 10 patients (Group 1, observational) had brain tissue oxygen (PbrO2) monitored, but not treated. The next 20 patients (Group 2, interventional) were treated according to brain tissue oxygen-guided algorithms aiming to improve cerebral oxygen availability. The 6-month neurological outcome of Group 2 patients was compared with that of Group 1 patients and with contemporary control patients (Group 3) treated without the use of brain oxygen monitoring.
FINDINGS: The mean duration of brain hypoxic episodes (PbrO2 <15 mmHg) was 106 minutes in Group 1, and 34 minutes in Group 2 (p=0.01). Brain tissue oxygen was <15 mmHg for 10% of monitoring time in Group 1 and 2.8% in Group 2 (p=0.12). The peak incidence of cerebral hypoxic events in both groups occurred during post-injury day 5. The mean Injury Severity Score (ISS) of patients experiencing cerebral hypoxia was higher than that of patients without cerebral hypoxic episodes (33.7 vs 24.2, p=0.04). There was no statistically significant difference in neurological outcome between those patients treated with and those without brain oxygen-guided therapy.
CONCLUSIONS: In TBI patients, brain tissue oxygen-guided therapy is associated with decreased duration of episodes of cerebral hypoxia. Larger studies are indicated to determine the effects of this therapy on neurological outcome.