Neuromonitoring of patients with severe traumatic brain injury at the bedside

Measurement of intracranial pressure (ICP) and arterial blood pressure is used to derive cerebral perfusion pressure (CPP) and to guide targeted therapy of severe traumatic brain injury (TBI) necessitating ICU admission. In this narrative review we discuss the evidence for ICP monitoring, CPP calculation, and ICP/CPP-guided therapy after severe TBI. Despite its widespread use, there is currently no class I evidence that ICP/CPP-guided therapy improves outcomes. Similarly, no class I evidence can currently advise the ideal CPP. 'Optimal' CPP is likely patient-, time-, and pathology-specific and related to cerebral autoregulation status. The fact that optimal CPP and autoregulation status varies between individual patients and over time makes it an attractive bedside tool to serve as a (simplified) model to investigate the use of autoregulation status to fine tune or give feedback on clinical treatments in individual sedated patients (optimal CPP concept).

Evidence is emerging for the role of other monitors (representing (local) metabolism, oxygen supply/use, perfusion, neuronal functioning) that enable the intensivist to employ an individualised multimodality monitoring approach in TBI. The management of TBI is likely to become increasingly based on a more comprehensive monitoring and management approach rather than relying on absolute numbers of ICP and CPP in isolation. This will allow individual optimisation of perfusion and therefore of oxygen and energy substrate delivery. We await further robust, high-quality evidence to support the benefits of using more sophisticated monitoring tools during the ICU management of TBI, but for the near future what is more important is to gain a greater understanding of the underlying pathophysiology.