Beyond intracranial pressure: monitoring cerebral perfusion and autoregulation in severe traumatic brain injury

Abstract

Purpose of reviewSevere traumatic brain injury (TBI) remains the most prevalent neurological condition worldwide. Observational and interventional studies provide evidence to recommend monitoring of intracranial pressure (ICP) in all severe TBI patients. Existing guidelines focus on treating elevated ICP and optimizing cerebral perfusion pressure (CPP), according to fixed universal thresholds. However, both ICP and CPP, their target thresholds, and their interaction, need to be interpreted in a broader picture of cerebral autoregulation, the natural capacity to adjust cerebrovascular resistance to preserve cerebral blood flow in response to external stimuli.Recent findingsCerebral autoregulation is often impaired in TBI patients, and monitoring cerebral autoregulation might be useful to develop personalized therapy rather than treatment of one size fits all thresholds and guidelines based on unidimensional static relationships.SummaryToday, there is no gold standard available to estimate cerebral autoregulation. Cerebral autoregulation can be triggered by performing a mean arterial pressure (MAP) challenge, in which MAP is increased by 10% for 20 min. The response of ICP (increase or decrease) will estimate the status of cerebral autoregulation and can steer therapy mainly concerning optimizing patient-specific CPP. The role of cerebral metabolic changes and its relationship to cerebral autoregulation is still unclear and awaits further investigation.

Developing a porcine model of severe traumatic brain injury induced by high amplitude rotational acceleration

“…Impairment of cerebrovascular autoregulation (CA), which is often seen in TBI, leads to inappropriate alterations of cerebrovascular resistance (CVR), potentially resulting in totally pressure-passive arterioles ( Dietvorst et al, 2023 ). In such scenario, cerebral perfusion pressure (CPP) becomes the main regulator of cerebral blood flow (CBF), with unbalanced negative impact of ICP and cerebral venous pressure (CVP).…”