Fig. 3.

The effect of pressure gradients on ICP monitoring. If the transducer is placed in the frontal-parietal region, as shown, the effect of the pressure gradients generated by event 1 (ICP1), for example cerebellar haematoma within the infra-tentorium, has the potential to be different from the effect of the pressure gradient that is generated by event 2 (ICP2), for example TBI. The three-dimensional pressure gradients generated against the cerebral tissue itself is what will ultimately affect cellular function—the core issue in raised ICP. Note that the cerebral blood vessels also generate pressure gradients, which are a result of both cerebral blood flow and cerebral blood volume, and are influenced by cerebral vascular reactivity. Diagram key: C1, superior sagittal sinus; C2, inferior sagittal sinus; C3 and C4, transverse sinus, A and B, lateral ventricles