PAT 20A/B Lecture Notes - Lecture 2: Brain Herniation, Cerebrospinal Fluid, Subarachnoid Space

• School: Ryerson University
• Department: Pathotherapeutics
• Course: PAT 20A/B
• Professor: Janet O'Connell

Document Summary

Week two: brain injury (closed head injury trauma) & increased intracranial. If not, leads to rapid increase in icp from normal range. Increased carbon dioxide, hydrogen ion concentration (acidosis) & oxygen (hypoxemia) all cause vasodilation and therefore increase cerebral blood flow which increases intracranial pressure (icp) Recall: mechanisms of injury: hypoxic and ischemic, excitotoxic. Compliance refers to the ratio of change in volume to the resulting change in pressure. The measure of the brain"s ability to maintain icp during changes in intracranial volume. With low compliance, small increases in volume result in greater increases in pressure. An increase in intracranial volume will produce little to no effect on icp if compliance is high. Factors that influence compliance: amount of volume increase, time frame for accommodation, size of intracranial compartments. Ischemia & changes in serum pco2 can also influence icp. 2nd: reduction of blood volume in the brain. When blood flow is reduced too much, acidosis, hypoxia, and ischemia develop.