Cerebral Perfusion and ICP

Question 1

What is the pathophysiological processes of brain haemorrhage?

Answer 1

Disruption of BBB 
Membrane failure, influx of Ca, cellular swelling 
Influx of inflammatory mediators 
Brain swelling 
Raised ICP

Question 2

What are the secondary effects of raised ICP?

Answer 2

Herniation syndromes

Decreased cerebral perfusion

Question 3

What is the Mono-Kellie doctrine?

Answer 3

Fixed volume of brain/CSF/blood is constant

Question 4

What is the equation for cerebral perfusion pressure?

Answer 4

CPP= MAP - ICP

Question 5

What is considered to be a normal CPP value?

Answer 5

80mmHg

Question 6

What is considered to be a normal MAP value?

Answer 6

90mmHg

Question 7

What is the normal range for ICP?

Answer 7

5-15mmHg

Question 8

What are the different forms of herniation syndrome?

Answer 8

Subfalcine herniation
Uncal hernation
Foramen magnum herniation

Question 9

What area of the brain is involved in subfalcine herniation?

Answer 9

Medial motor cortex

Question 10

What area of the brain is involved in uncal herniation?

Answer 10

Third cranial nerve

Ipsilateral corticospinal tracts

Question 11

What area of the brain is involved in formate magnum herniation?

Answer 11

Brain stem centres

Question 12

How is ICP managed?

Answer 12

Mannitol given intermittently 
Taken to ITU for ICP bolt 
Head position 30 degrees 
Nothing to impede venous drainage 
Fully sedated and paralysed

Question 13

What are the surgical options to reduce ICP?

Answer 13

Craniotomy and evacuation of clot
External ventricular drainage
Decompressive craniectomy