The Impact of Invasive Brain Oxygen Pressure Guided Therapy on the Outcome of Patients with Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Abstract

Traumatic brain injury (TBI) is a major public health burden, causing death and disability worldwide. Intracranial hypertension and brain hypoxia are the main mechanisms of secondary brain injury. As such, management strategies guided by intracranial pressure (ICP) and brain oxygen (PbtO 2 ) monitoring could improve the prognosis of these patients. Our objective was to summarize the current evidence regarding the impact of PbtO 2 -guided therapy on the outcome of patients with TBI. We performed a systematic search of PubMed, Scopus, and the Cochrane library databases, following the protocol registered in PROSPERO. Only studies comparing PbtO 2 /ICP-guided therapy with ICP-guided therapy were selected. Primary outcome was neurological outcome at 3 and 6 months assessed by using the Glasgow Outcome Scale; secondary outcomes included hospital and long-term mortality, burden of intracranial hypertension, and brain tissue hypoxia. Out of 6254 retrieved studies, 15 studies (n = 37,245 patients, of who 2184 received PbtO 2 -guided therapy) were included in the final analysis. When compared with ICP-guided therapy, the use of combined PbO 2 /ICP-guided therapy was associated with a higher probability of favorable neurological outcome (odds ratio 2.21 [95% confidence interval 1.72-2.84]) and of hospital survival (odds ratio 1.15 [95% confidence interval 1.04-1.28]). The heterogeneity (I 2 ) of the studies in each analysis was below 40%. However, the quality of evidence was overall low to moderate. In this meta-analysis, PbtO 2 -guided therapy was associated with reduced mortality and more favorable neurological outcome in patients with TBI. The low-quality evidence underlines the need for the results from ongoing phase III randomized trials.

“NeuroVanguard”: a contemporary strategy in neuromonitoring for severe adult brain injury patients

“…However, the individualization of therapies based on the combination of ICP and PbtO 2 also necessitates clinical validation and have several limitations (see next paragraph ). A systematic review, primarily comprising 15 studies (involving a total of 37,245 patients), although predominantly observational with an overall low quality of evidence, indicated that the use of combined ICP/PbtO 2 -guided therapy, as opposed to ICP-guided therapy alone, was significantly associated with a higher likelihood of achieving a favorable neurological outcome and improved hospital survival [ 47 ]. In a phase II randomized trial conducted across 10 neuro-ICUs in the USA, a management protocol incorporating continuous PbtO 2 monitoring alongside ICP monitoring demonstrated a notable reduction in the duration of brain tissue hypoxia among severe TBI patients, in comparison with those monitored for ICP alone [ 48 ], with a nonsignificant improvement in the proportion of patients achieving a favorable neurological outcome at 6 months.…”

Brain tissue oxygen partial pressure monitoring and prognosis of patients with traumatic brain injury: a meta-analysis

“…The rate of mortality in the PbtO 2 monitoring group was 29.0% across all studies included in our analysis, which is different from the previously reported rate based on a meta-analysis by Xie [ 4 ]. Studies have demonstrated that brain hypoxia is associated with poor prognosis after TBI and optimizing PbtO 2 can improve recovery and survival rates [ 26 ]. Four observational studies [ 19 , 20 , 22 , 23 ] and two randomized controlled trials [ 16 , 25 ] included in this meta-analysis demonstrated that when PbtO 2 was incorporated into clinical management decisions, neural function exhibits statistically significant benefits.…”

All Over the MAP! Cerebral Autoregulation and Optimizing Brain Tissue Oxygenation After Traumatic Brain Injury*

“…Early interventions after acute traumatic brain injury (TBI) provide clinicians an opportunity to prevent secondary injury and improve neurologic outcomes. One avenue is to optimize brain tissue oxygenation (Pbt o 2 ) (1). Many variables impact cerebral blood flow (CBF) and subsequent brain tissue oxygen delivery and extraction, including systemic blood pressure, arterial blood oxygen and C o 2 levels, serum pH, hemoglobin, microvascular shunts, and metabolic demands (2, 3).…”

“…CBF can be assessed directly at the bedside using transcranial Doppler (TCD) ultrasound monitoring. Alternatively, the pressure reactivity index is calculated as a dynamic correlation coefficient between ICP and mean arterial pressure (MAP), which can be plotted against CPP to produce patient-specific optimal autoregulatory capacity (CPP opt ) (1). Both TQIP and SIBCIC recommend performing a MAP challenge to assess the autoregulatory capacity of CBF.…”

“…They further encourage clinicians to incorporate multimodal neuromonitoring in patients with severe TBI to identify patient-specific parameters to improve CBF. Increased use of direct measurements from Pbt o 2 monitoring and cerebral autoregulation testing to guide therapeutic interventions holds promise to improve functional status in patients after severe TBI (1, 5, 6, 13). While indiscriminate MAP augmentation may lead to harm in defined cohort of patients, increasing CBF using various techniques to increase time spent at CPP opt may provide significant benefits (11).…”