Brain Injury Flashcards
What is “Brain Injury?”
increased intercranial volume and pressure
The cranium contains 3 compartments.
What are they? What percentage does each take up?
Are they fixed or do they fluctuate?
- Brain tissue (80%), fixed
- Blood (10%), fluctuates
- CSF (10%), fluctuates
The 3 contents in the cranium make up what pressure?
ICP
What should the ICP be?
5-15 mmHG
Define CPP: what should its range be?
Cerebral Perfusion Pressure (blood flow to the brain)
(70-100 mmHG)
What is the equation for CPP?
CPP = MAPP - ICP
What is the equation for MAP?
Systolic + Diastolic x 2
__________________
3
What happens if the CCP is less than 40?
Brain ischemia and can lead to brain infarction
The patho of Brain injury involves munro kellies hypothesis: what is her hypothesis?
Physiologic minor fluctuations between the 3 compartments when they are compensating for eachother
When trauma occurs, this is NOT a normal physiologic proccess, but what is occuring in the compartments of the cranium?
Fluctuation of 1 or more of the 3 compartments, causing an increase of ICP
What is often associated with trauma causing the fluctuation between the 3 compartments?
Proliferation of a lesion (tumor or hemmorhage)
Is the skull expandable?
NO dummy.
When the 3 compartments are fluctating, they follow a pattern of compliance. What is it? 1. 2. 3.
- 1st compliance = displacement and or reabsorment of CSF
- 2nd compliance = reduced blood flow (aiming to decrease ICP, but leads to problems with hypoxia)
- Compression or displacement of the brain (DEATH!)
Cushings Reflex:
1. What is this in resposne to?
2. Latter response to what?
3. What happens to the MAP?
4. What is the Cushing's Triad?
1.
2.
3.- Ischemia
- Latter response to increased ICP
- MAP goes up to 270
- Widening pulse pressure (OR HTN)
- Reflex bradycardia
- Ireggular breathing
Why does the MAP (aka BP) increase so much?
Trying to increase pressure to be able to overcome the pressure in order to be able to reach the brain, but it is unable to do so.
Why does reflex bradycardia occur?
Reflex to the increased ICP
Hemorrhage and Hematomas: what is the way that they form?
Vascular damage –> Hemorrhage –> Hematoma
What is a hematoma?
Solid swelling of clotting blood
Hematomas cause..
- Loss of function where?
- Which leads to loss of function where?
- Loss of neural function (affeced area)
2. Loss of function at targeted area
Hematomas are based on what?
What are the 3 we look at?
Location.
- Intracerebral hematoma
- Subdural Hematoma
- Epidural Hematoma
Intracerebral Hematoma:
- Where is it?
- Where is this putting pressure on?
- In the brain tissue itself
2. Putting pressure outward to soft tissue surrounding
Subdural Hematoma:
- Where is it?
- What is it putting pressure on?
- This hematoma involves an encapsulated mass, explain the proccess of this.
- Between dura matter and arachnoid matter
- Putting pressure on the soft tissue of the brain
- Encapsulated mass –> lysis –> increased concentration –> fluid efflux from surrounding cells into the hematoma
Epidural Hematoma:
- Where is it?
- What is it putting pressure on?
- What is the main artery affected here?
- This is the most common hematoma with what time of injury or fracture?
- Is this hematoma the most superficial, or the most deep?
- Between dura matter and skull
- On the brain tissue
- Middle meningial artery
- Head fracture or injury
- Most superficial of the hematomas
When do hematomas typically present? (at what age?) d/t what?
past age 50, d/t weakening of the vessel wall.
