ABSTRACT
An understanding of raised intracranial pressure (ICP) pathophysiology is crucial to understanding the presentation and treatment of the common neurosurgical conditions (Summary box 40.1).
Pathophysiology Normal intracranial pressure Normal ICP varies from 5 to 15 mmHg in the adult at rest. ICP varies with venous pressure and is thus affected by factors such as gravitational drainage and manoeuvres that raise intrathoracic pressure (coughing, Valsalva, positive pressure ventilation) or lower it (normal inspiration). Normal values in small children and infants are lower than for adults.
