The Monro Kellie Hypothesis describes how a raised intracranial pressure arises. It also gives us some insight into how we can attempt to control it.
There are three main elements with our skulls. The brain tissue itself, the blood that perfuses the tissue, and the cerebral spinal fluid (CSF).
Raised ICP arises when one or more of these elements grows in volume but can't expand due to the confines of the skull. This video describes the process using some simple animations.
If you find this video useful you may want to look at some of the other videos on controlling a raised ICP. See Carbon Dioxide and ICP Management and Patient Positioning and ICP.
All our body's organs will suffer if our blood pressure drops to low. Insufficient pressure will lead to an inadequate supply of oxygenated blood to meet the organs' requirements.
The brain is no exception. It is a hungry organ that requires a constant supply of oxygen and nutrients if it is to function and remain healthy. Cerebral perfusion pressure refers to the blood pressure required to adequately meet its needs.
This video describes how to calculate the brains requirements after brain trauma, taking into account blood pressure and intracranial pressure (MAP-ICP).