Introduction: The utility of monitoring brain tissue oxygenation (PBO2) remains uncertain in the setting of traumatic brain injury. ICU care guided by PBO2 values has been suggested to decrease mortality; few studies have focused on more descriptive functional outcome measurements or neuropsychological testing. We sought to compare patients with severe TBI requiring intraparenchymal monitoring consisting of both intracranial pressure and oxygen or intracranial pressure (ICP) sampling alone.
Methods: A retrospective review of patients with severe TBI managed in the ICU with PBO2 and ICP (Licox) or only ICP (Camino) monitoring of frontal cortex. PBO2 guided interventions were based on three escalating treatment tiers to maintain a value >20 mm Hg. ICP was directed to maintain a value <20 mm Hg. Concurrent hourly PBO2, ICP, CPP, Hgb, PaCO2, FiO2, and PaO2 were extracted from the electronic medical record. Subjects in the PBO2-ICP group were matched by age (within 5 years) and sex to those in the ICP only group. All received a comprehensive neuropsychological testing battery at 30 and 90 days following the date of injury. Composite standardized scores were developed from the testing battery at 30 (CVLT-II subtests: Trials 1 - 5 and Long delay free recall) and 90 (Processing speed index, Trails A & B, Digit Span scaled score, Stroop I & II, and Adjusted COWA) days. The two groups were compared in testing, Post Traumatic Amnesia (PTA), Disability Rating Scale (DRS), and Extended Glasgow Outcome Score (GOSE).
Results: The ICU and hospital stay was significantly greater in the PBO2-ICP group. No differences were detected in GOSE or DRS. The mean number of days of patients reported having post traumatic amnesia was 34 days. No differences were detected in comparing the standardized composite scores from neuropsychological testing. The most significant predictor was age in determining outcome.
Conclusions: PBO2-ICP monitoring in the setting of severe TBI is associated with longer ICU and hospital duration. There are no differences in functional outcome measures and neuropsychological testing at 30 and 90 days following TBI.
Patient Care: Critically evaluate the role of brain tissue oxygen monitoring in TBI.
Consider alternative outcome measures to the GOSE and mortality.
Learning Objectives: Examine outcome measures related to PBO2