The authors sought to describe changes in clinical management associated with brain tissue oxygen (PbO2) monitoring and how these changes affected outcomes and resource utilization.
The cohort study comprised 629 patients admitted to a Level I trauma center with a diagnosis of severe traumatic brain injury over a period of 3 years. Hospital mortality rate, neurological outcome, and resource utilization of 123 patients who underwent both PbO2 and intracranial pressure (ICP) monitoring were compared with the same measures in 506 patients who underwent ICP monitoring only. The main outcomes were hospital mortality rate, functional independence at hospital discharge, duration of mechanical ventilation, hospital length of stay, and hospital cost. Multivariable regression with robust variance was used to estimate the adjusted differences in the main outcome measures between patient groups. The models were adjusted for patient age, severity of injury, and pathological features seen on head CT scan at admission.
On average, patients who underwent ICP/PbO2 monitoring were younger and had more severe injuries than patients who received ICP monitoring alone. Relatively more patients treated with PbO2 monitoring received osmotic therapy, vasopressors, and prolonged sedation. After adjustment for baseline characteristics, the hospital mortality rate was, if anything, slightly higher in patients undergoing PbO2-guided management than in patients monitored with ICP only (adjusted mortality difference 4.4%, 95% CI −3.9 to 13%). Patients who underwent PbO2-guided management also had lower adjusted functional independence scores at hospital discharge (adjusted score difference −0.75, 95% CI −1.41 to −0.09). There was a 27% relative increase (95% CI 6–53%) in the median hospital length of stay when the PbO2 group was compared with the ICP-only group.
The mortality rate in patients with traumatic brain injury whose clinical management was guided by PbO2 monitoring was not reduced in comparison with that in patients who received ICP monitoring alone. Brain tissue oxygen monitoring was associated with worse neurological outcome and increased hospital resource utilization.
Abbreviations used in this paper:AIS = Abbreviated Injury Scale; CPP = cerebral perfusion pressure; FIM = Functional Independence Measure; GCS = Glasgow Coma Scale; FiO2 = fraction of inspired O2; ICP = intracranial pressure; ICU = intensive care unit; ISS = Injury Severity Scale; LOS = length of stay; MABP = mean arterial blood pressure; PbO2 = brain tissue O2; SAH = subarachnoid hemorrhage; SAPS II = Simplified Acute Physiology Score II; TBI = traumatic brain injury.
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