Intracranial pressure monitoring in severe traumatic brain injury

In a trial recently published in the New England Journal of Medicine, Chesnut and colleagues attempted to provide class I evidence on the impact of intracranial pressure (ICP) monitoring on functional and neuropsychological outcomes after traumatic brain injury (TBI).1 The authors concluded that there was no difference in the primary outcome—a composite of 21 equally weighted components—between the group of patients who had ICP monitoring and the group that did not. This is a landmark study; undertaking such a trial has long been considered impossible because most experts considered ICP monitoring the primary basis for managing patients with severe TBI.2 However, the findings require some scrutiny before we can consider a fundamental change in our approach to managing these patients.

Since it was introduced into clinical practice more than 50 years ago, ICP monitoring has gradually become the standard of care in most centres that treat patients with severe TBI in the United Kingdom, North America, and most developed countries.2 The physiological basis of ICP monitoring in TBI is twofold. Firstly, increasing ICP indicates escalating mass effect (from haematomas, contusions, or diffuse brain swelling). If escalating mass effect is left untreated, brain herniation and death will follow. Secondly, ICP has a direct impact on cerebral perfusion pressure (the mean arterial blood pressure minus ICP). It …