Increased Intracranial Pressure
Our brain is a super cool organ. As it sits encased in the cranium, it is the machine of all machines when it comes to making our body function. Neurological emergencies are one of my favorite subjects (second to hypovolemic traumas) that really peaks my interest. The Monro-Kellie doctrine describes perfectly why neurological emergencies can occur. Our cranium is a ridged box that houses a constant sum of our brain, cerebral spinal fluid and blood vessels. Due to the cranium being a fixed size, these three things are so tightly auto-regulated that any insult to the noggin can have drastic effects. When one of these three increases in size, the functionality of the other two are compromised. We can have alterations causing increased cranial pressure due to cerebral edema, mass formation, intracranial bleeding, and or the inability to regulate, produce or remove cerebrospinal fluid. In this blog, we are going to discuss normal anatomical and physiological aspects of the brain, signs and symptoms of increased intracranial pressure and we will hit it home with interventions to help mitigate increased intracranial pressure in the prehospital setting. The Skull consists of eight cranial bones that are connected by immovable sutures. The Cranial floor houses many holes for the neurovasculature and cerebrospinal fluid to enter and exit the skull. Of importance is the Foramen Magnum, which is the largest opening at the base of the skull that allows the spinal cord to connect to the brain stem. Let’s take a look at what the cranium houses, because it’s not just “the brain”. Per the Monro-Kellie doctrine, the cranium is a fixed/ridged box whose volume tends to remain constant. In an attempt to simplify the reality of increased intracranial pressure, we have three main components that affect ICP: The Brain, Cerebrospinal Fluid and Blood.
1. THE BRAIN: Ok, I need to just prepare you guys. I’m about to throw some super cool shit down. The brain accounts for 2% of our body weight BUT it accounts for 15% of our total blood flow. Every 24 hours the brain requires: 1000L of blood flow, 71L of Oxygen and 100g of glucose. The brain utilized 80% of the cranial space. (10) That blows my mind 🤯🤓 (terrible pun