Assessment of the pressure of the cerebrospinal fluid in the head with a sensor inserted through the skull. Intracranial pressure monitoring is used in the management of critically ill patients, especially those who have suffered severe brain injury or intracranial bleeding. In healthy people intracranial pressures range between 0 and 10 mm Hg. Pressures higher than 20 mm Hg increase the risk of compression or herniation of the brain or brainstem.