Continuous monitoring of intracranial compliance in neurointensive care (Editorial by invitation)

Excerpt

Evaluation of intracranial compliance, i.e. the ability to compensate for increased intracranial volume (e.g. due to an extracerebral haematoma, contusions or brain oedema) may add valuable information to routine ICP monitoring in neurointensive care. The Monroe-Kellie doctrine provides the basis for the volume-pressure interaction stating that under normal physiological conditions, the total volume of the three compartments in the rigid skull (circulating blood, brain and CSF) is constant and if the volume of one compartment is increasing, this is compensated by a decrease in volume of another department. With an increase in lesion volume, the total intracranial volume is initially kept constant by reductions in blood volume (due to vasocompression), and through displacement of CSF. When this volume compensatory reserve is exhausted, ICP increases exponentially. Compliance refers to the magnitude of the change in pressure induced by an increase in volume (∆V/∆P), and indicates where the patient is on the pressure-volume curve. …