Outcomes associated with brain tissue oxygen monitoring in patients with severe traumatic brain injury undergoing intracranial pressure monitoring

Abstract

OBJECTIVE Brain tissue oxygen monitoring combined with intracranial pressure (ICP) monitoring in patients with severe traumatic brain injury (sTBI) may confer better outcomes than ICP monitoring alone. The authors sought to investigate this using a national database. METHODS The National Trauma Data Bank from 2013 to 2017 was queried to identify patients with sTBI who had an external ventricular drain or intraparenchymal ICP monitor placed. Patients were stratified according to the placement of an intraparenchymal brain tissue oxygen tension (PbtO2) monitor, and a 2:1 propensity score matching pair was used to compare outcomes in patients with and those without PbtO2 monitoring. Sensitivity analyses were performed using the entire cohort, and each model was adjusted for age, sex, Glasgow Coma Scale score, Injury Severity Score, presence of hypotension, insurance, race, and hospital teaching status. The primary outcome of interest was in-hospital mortality, and secondary outcomes included ICU length of stay (LOS) and overall LOS. RESULTS A total of 3421 patients with sTBI who underwent ICP monitoring were identified. Of these, 155 (4.5%) patients had a PbtO2 monitor placed. Among the propensity score–matched patients, mortality occurred in 35.4% of patients without oxygen monitoring and 23.4% of patients with oxygen monitoring (OR 0.53, 95% CI 0.33–0.85; p = 0.007). The unfavorable discharge rates were 56.3% and 47.4%, respectively, in patients with and those without oxygen monitoring (OR 1.41, 95% CI 0.87–2.30; p = 0.168). There was no difference in overall LOS, but patients with PbtO2 monitoring had a significantly longer ICU LOS and duration of mechanical ventilation. In the sensitivity analysis, PbtO2 monitoring was associated with decreased odds of mortality (OR 0.56, 95% CI 0.37–0.84) but higher odds of unfavorable discharge (OR 1.59, 95% CI 1.06–2.40). CONCLUSIONS When combined with ICP monitoring, PbtO2 monitoring was associated with lower inpatient mortality for patients with sTBI. This supports the findings of the recent Brain Oxygen Optimization in Severe Traumatic Brain Injury phase 2 (BOOST 2) trial and highlights the importance of the ongoing BOOST3 trial.

Invasive brain tissue oxygen and intracranial pressure (ICP) monitoring versus ICP-only monitoring in pediatric severe traumatic brain injury

“…18 In addition, many adult studies measure outcome by examining mortality rate or discharge location. 14,16,18 These outcomes were not as apparent in our study: for example, there were only 3 deaths and only 2 patients were discharged to another institution. Another difference between our results and findings compared to the adult population is the inherent difference in children recovery patterns.…”

“…Although these correlations became insignificant after controlling for age and sex, these trends aligned with a recent study in the adult severe TBI population that found significantly increased ICU LOS and duration of mechanical ventilation in patients receiving ICP + PbtO 2 monitoring, compared to patients receiving only ICP monitoring. 14 Despite the increased LOS and mechanical ventilation period, which could be due to adverse effects from the treatments for cerebral hypoxia, the ICP + PbtO 2 group demonstrated lower mortality than the ICPonly group. 14 In a phase 2 safety and feasibility BOOST-II trial for adult severe TBI, a reduction in cerebral hypoxia time and a trend toward lower mortality and improved GOS-E outcome at 6 months were demonstrated in the ICP + PbtO 2 treatment group compared with the ICP-only treatment group.…”

“…14 Despite the increased LOS and mechanical ventilation period, which could be due to adverse effects from the treatments for cerebral hypoxia, the ICP + PbtO 2 group demonstrated lower mortality than the ICPonly group. 14 In a phase 2 safety and feasibility BOOST-II trial for adult severe TBI, a reduction in cerebral hypoxia time and a trend toward lower mortality and improved GOS-E outcome at 6 months were demonstrated in the ICP + PbtO 2 treatment group compared with the ICP-only treatment group. 18 The ongoing BOOST-III adult study is a multi-institutional randomized clinical trial to determine the comparative effectiveness of guided treatment with + PbtO 2 versus that with only ICP (ClinicalTrials.gov identifier: NCT03754114).…”

“…The Brain Tissue Oxygen Monitoring and Management in Severe Traumatic Brain Injury (BOOST-II) randomized control trial, in addition to other studies, has examined primarily adult patients with severe TBI using ICP and PbtO 2 monitoring and revealed improved outcomes and reduced mortality rates. [14][15][16][17][18] The current BOOST-III trial enrolls patients 14 years of age and older (ClinicalTrials.gov identifier: NCT03754114). Similar randomized controlled trials evaluating the addition of PbtO 2 on patient outcomes have not been conducted in the pediatric TBI population.…”

Cerebral metabolic derangements following traumatic brain injury

“…1), and time spent above this threshold within the first 72 h post TBI has been shown to be associated with poor outcome [ ]. Recent data suggest a survival benefit in severe TBI patients when PbtO 2 and ICP monitoring are combined as compared with ICP monitoring alone [2], and consensus guidelines for their use have recently been published [15 & ]. Pathophysiological heterogeneity predicates the need for physiological imaging, and while both computed tomography and MRI can provide perfusion imaging, the gold standard technique for understanding cerebral metabolic derangements is PET.…”