Brain monitoring in severe head injury: A practical guide

There is, as yet, no specific therapy available for post-traumatic brain damage; the treatment of head injury is therefore aimed at limitation of secondary damage at the cellular, whole organ and systemic level. The purpose of monitoring the injured brain is twofold: 1. to obtain a better understanding of the mechanisms by which pathophysiological processes further damage the injured brain. 2. to continuously detect potentially harmful influences and allow them to be reversed before damage is done. In this review, we provide a general overview of mechanisms of brain damage due to high intracranial pressure (ICP) and discuss the following 'brain specific' haemodynamic monitoring techniques: • ICP/CPP (cerebral perfusion pressure) monitoring; • jugular vein saturation (SjO₂) monitoring; • cerebral oxygen monitoring (PtiO₂) and near infra-red spectroscopy (NIRS); • brain temperature monitoring; • cerebral blood flow (CBF) monitoring; and • transcranial Doppler. We also discuss the role of functional techniques such as electroencephalogram (EEG) and evoked potential monitoring. This article gives an overview of the techniques currently available in a rapidly expanding field within neuro-intensive care, mainly for the interest of trauma surgeons, intensivists, and others with a practical need to understand the monitoring of the injured brain.