CSF, ICpressure and cerebral blood flow

Question 1

what is monroe-kellie doctrine

Answer 1

skull is closed compartment with fixed volume - change in volume = change in pressure

Question 2

what is content of skull (3)

Answer 2

1. brain
2. blood
3. CSF

Question 3

where is CSF made

Answer 3

choroid plexu

Question 4

what is total CSF col

Answer 4

120ml

Question 5

what is CSF flow

Answer 5

lateral vent>3rd vent>cerebral aqueduct>4th vent.>subarachnoid space>absorbed by arachnoid villi

Question 6

where is CSF

Answer 6

30ml in vents, the rest in subarachnoid space

Question 7

what is normal ICP

Answer 7

9-12mmH2O

Question 8

what can change ICP

Answer 8

changes in volume of intracranial vault - mass effect, fluid leak

Question 9

what are 2 stages of high ICP

Answer 9

1. organ dysfunction (smonolence, confusion)

2. organ failure (loss of cons., coma, death)

Question 10

how much of blood does brain get

Answer 10

15% of body

Question 11

what is normal brain perfusion

Answer 11

50-55 ml/min/100g

Question 12

what are 2 problem levels

Answer 12

ischemia when under 18-20

cell death under 8-10

Question 13

what is formula for CBF

Answer 13

CBF = Cerebral perfusion pressue/CVR

Question 14

what is CPP formula

Answer 14

MAP-ICP

Question 15

3 causes of intracranial hypertension

Answer 15

1. obstructed CSF flow or absorbtion
2. increased intracranial contents (tumor or hemmorage)
3. generalized brain edema (trauma, hepatic encephalopathy)

Question 16

2 types of hydrocephalus

Answer 16

1. non-communicating (block)

2. communicating (poor abs., or rarely too much production)

Question 17

3 causes of immediate morbidity or mortality in subarachnoid hemm

Answer 17

1. rupture associated trauma
2. acute hydroceph
3. repeat hemmoracg

Question 18

what is ventriculoperitoneal shunt

Answer 18

valve that drains the fluids into the peritoneum

Question 19

what is aqueductal stenosis

Answer 19

non-communicatin hydroceph

Question 20

3 ways to decrease ICP

Answer 20

1. lower CSF vol
2. lower CBV
3. releive mass effect

Question 21

how to decrease CSF (3)

Answer 21

1. external diversion
2. lower production - acetezolamide - carbonic anydrase inhib
3. decrease brain ISF - mannitol

Question 22

4 ways to decrease CBV

Answer 22

1. normalize pCO2 and O2
2. max venous outflow (vertical)
3. decrease pCOS - hypervent
4. increase CPP – paradoxically can lower ICP

Question 23

2 ways to lower mass effect

Answer 23

1. expand space

2. remve tumor