The impact of brain tissue oxygenation monitoring on mortality in adult patients with severe traumatic brain injuries: a systematic review

Background: Intracranial pressure (ICP) monitoring and cerebral perfusion pressure (CPP) monitoring are long established adjuncts in the management of traumatic brain injuries (TBIs). However, brain tissue oxygenation (PbtO2) monitoring, used in conjunction with ICP or CPP monitoring, is an additional element that could be used in directing the management of TBIs.

Aims: To determine the impact of PbtO2 monitoring on mortality in adult patients with severe TBIs. 

Methods: A systematic review of electronic databases was performed in October 2021. A total of six articles were identified for inclusion. Data were extracted using a pre-designed extraction tool. Analysis was undertaken using RevMan for the mortality rates and a narrative analysis for the secondary outcomes.

Findings: A total of 926 participants were evaluated. Of these, 269 received PbtO2 monitoring. There was no significant difference in mortality rates between the groups, with the PbtO2 and ICP/CPP groups having a mortality rate of 25% (72/284) and 26% (171/662), respectively. The odds ratio was calculated as 0.88 (0.63–1.23, P=0.45) suggesting a 37% reduction in the odds of mortality when PbtO2 is used. However, the 95% confidence intervals do indicate a non-statistical finding. Morbidity rates between the two groups were also similar, with some limited evidence (one study) demonstrating a higher fiscal cost associated with PbtO2 monitoring.

Conclusions: There was no significant difference in mortality or morbidity rates between the two groups. Based on these results, this systematic review cannot support the addition of PbtO2 monitoring to guide the treatment of adult patients with severe TBIs.