Cerebral Perfusion Pressure

Cerebral perfusion pressure (CPP) is a concept within the field of neurosurgery. It is a measure of the difference between a patient's mean arterial pressure (MAP) in the arteries leading to the brain, and intracranial pressure (ICP) within the skull. The formula generally used to calculate CPP is CPP = MAP - ICP. The rate of perfusion of blood in the brain is determined by the pressure gradient between these two variables. An adequate CPP is essential for sustaining the brain's metabolic needs and regulates its function. CPP is used to evaluate the health of the internal structures of the central nervous system by monitoring the flow of blood to the brain. In neurosurgery, it is commonly monitored during the course of a patient's care in order to ensure that appropriate levels of cerebral vascular resistance, and hence CPP, are maintained. A patient's average CPP will vary depending on the patient's age, fluids and medications administered, severity of illness, and at times the position of the patient. Monitoring of CPP is necessary in a range of neurological problems such as head trauma, several forms of cerebrovascular diseases, subarachnoid hemorrhage, hypertensive encephalopathy, hydrocephalus, and intracranial space occupying lesions. If the CPP is monitored carefully, it can lead to the prevention of complications associated with them. A severely low CPP, when present, can cause a patient to become drowsy, confused, unable to concentrate, or even enter into a coma. In general, an elevated CPP is a sign of adequate perfusion of the brain and can be associated with good clinical outcome. However, too high of a CPP for too long can cause high intracranial pressure, which could in turn cause brain herniation. Therefore, it is important to make sure that CPP is not too high or too low. It must always be kept within the range of proper parameters for the patient's condition.