Utilization of Brain Tissue Oxygenation Monitoring and Association with Mortality Following Severe Traumatic Brain Injury

Abstract

Background: The aim of this study was to describe the utilization patterns of brain tissue oxygen (PbtO₂) monitoring following severe traumatic brain injury (TBI) and determine associations with mortality, health care use, and pulmonary toxicity.

Methods: We conducted a retrospective cohort study of patients from United States trauma centers participating in the American College of Surgeons National Trauma Databank between 2008 and 2016. We examined patients with severe TBI (defined by admission Glasgow Coma Scale score ≤ 8) over the age of 18 years who survived more than 24 h from admission and required intracranial pressure (ICP) monitoring. The primary exposure was PbtO₂ monitor placement. The primary outcome was hospital mortality, defined as death during the hospitalization or discharge to hospice. Secondary outcomes were examined to determine the association of PbtO₂ monitoring with health care use and pulmonary toxicity and included the following: (1) intensive care unit length of stay, (2) hospital length of stay, and (3) development of acute respiratory distress syndrome (ARDS). Regression analysis was used to assess differences in outcomes between patients exposed to PbtO₂ monitor placement and those without exposure by using propensity weighting to address selection bias due to the nonrandom allocation of treatment groups and patient dropout.

Results: A total of 35,501 patients underwent placement of an ICP monitor. There were 1,346 (3.8%) patients who also underwent PbtO₂ monitor placement, with significant variation regarding calendar year and hospital. Patients who underwent placement of a PbtO₂ monitor had a crude in-hospital mortality of 31.1%, compared with 33.5% in patients who only underwent placement of an ICP monitor (adjusted risk ratio 0.84, 95% confidence interval 0.76-0.93). The development of the ARDS was comparable between patients who underwent placement of a PbtO₂ monitor and patients who only underwent placement of an ICP monitor (9.2% vs. 9.8%, adjusted risk ratio 0.89, 95% confidence interval 0.73-1.09).

Conclusions: PbtO₂ monitor utilization varied widely throughout the study period by calendar year and hospital. PbtO₂ monitoring in addition to ICP monitoring, compared with ICP monitoring alone, was associated with a decreased in-hospital mortality, a longer length of stay, and a similar risk of ARDS. These findings provide further guidance for clinicians caring for patients with severe TBI while awaiting completion of further randomized controlled trials.

Keywords: ICP monitoring; TBI; Trauma.