ICP Flashcards
What are the three main components of the Intracranial vault?
- brain: 80-85%
- blood: 5-10%
- CSF: 10-15%
The _______ _________ is a rigid, non-expandable structure that protects the brain.
Adult cranium
At what ICP is there limit of compensation?
Up to ~ 20 mmHg
At what ICP is focal ischemia seen?
20-50mmHg
At what ICP is there global ischemia?
> 50mmHg
What is the normal ICP?
5-15 mmHg
When should treatment for intracranial HTN be initiated?
There is no defined set point at which treatment for intracranial HTN should be initiated, but levels above 20 mmHg are usually treated.
However, it is probably more important to maintain an adequate cerebral perfusion pressure.
Where is CSF produced?
By the choroid plexus in the cerebral ventricles
Where is CSF found?
Surrounding the brain and spinal cord
How much CSF is produced?
500 cc produced every 24 hours
Total volume of CSF is roughly 150 cc
How is CSF drained for chronic hydrocephalus?
With VP shunts
How is CSF drained during acute increases in ICP?
With ventriculostomies
T/F CSF can be drained during aortic aneurysm surgery to improve spinal cord perfusion.
True
What causes increased “brain” volume?
- tumor
- swelling (edema)
What are 3 types of tumors that cause increased “brain” volume?
- meningioma (operable)
- glioblastoma (more invasive)
- pituitary tumor
What are causes of cerebral edema?
- traumatic brain injury
- non-traumatic causes such as ischemic stroke, cancer, or brain inflammation due to meningitis or encephalitis
- vasogenic edema
- the blood brain barrier (BBB) may break down, allowing fluid to accumulate in the brain’s extracellular space
- altered metabolism may cause brain cells to retain water, and dilution of the blood plasma may cause excess water to move into brain cells
Fast travel to high altitude without proper acclimatization can cause ______ ________ _________ ________.
High altitude cerebral edema (HACE)
What is the most rapid and effective means of decreasing tissue water and brain bulk?
Osmotherapy
What is the most popular osmotic agent?
Mannitol
What are two other types of medications used in the acute correction of cerebral edema?
- diuretics: the osmotic effect can be prolonged by the use of loop diuretics (furosemide) after the osmotic agent infusion
- corticosteroids: corticosteroids lower ICP primarily in vasogenic edema because of their beneficial effect on the blood vessel
What are neurologic complications associated with acute hyponatremia attributed to?
Cerebral edema and increased ICP
What is the most common cause of central pontine myelinolysis (CPM)?
Overly rapid correction of low blood sodium levels
What is CMRO2 and CBF?
CMRO2: Cerebral metabolic rate of oxygen
CBF: cerebral blood flow
What is CPP?
Cerebral perfusion pressure
CPP= MAP - ICP or CVP, whichever is greater