Cerebral Perfusion & ICP

Question 1

what does GCS stand for?

Answer 1

glasgow coma score

Question 2

what are the three components of the GCS ?`

Answer 2

best eye response
best verbal response
best motor response

Question 3

under which GCS is someone in a coma?

Answer 3

<8

Question 4

on a CT scan how can you tell that a brain is swollen?

Answer 4

can’t see ventricles or they have a reduced size

can’t see sulci

Question 5

what does brain swelling result in ?

Answer 5

increased intracranial pressure

Question 6

what four pathophysiological processes result in brain swelling ?

Answer 6

1. haemorrhage
2. disruption of the BBB which increases extra cellular fluid
3. membrane failure which results in an increase of Ca
4. influx of inflammatory mediators

Question 7

what is vasogenic oedema ?

Answer 7

when there is an increase in extra cellular fluid

Question 8

what is cytotoxic oedema ?

Answer 8

when there is an increase of Ca ions and causes swelling of cells

Question 9

state two secondary effects of raised intracranial pressure ?

Answer 9

1. herniation syndromes

2. decreased cerebral perfusion

Question 10

does decreases cerebral perfusion result in a higher or lower GCS ?

Answer 10

lower GCS

Question 11

is there is fixed volume in adults and babies ?

Answer 11

in adults there is a fixed volume but in babies their sutures haven’t fuse yet so they don’t have a fixed volume

Question 12

what three components make the fixed volume of the intracranial space?

Answer 12

brain
CSF
blood

Question 13

what is the equation used to measure the volume of the intracranial space?

Answer 13

Monro-Kellie Doctrine

Question 14

how can the intracranial space compensate for an increase of pressure ?

Answer 14

increase venous output

increase output of CSF to subarachnoid space

Question 15

how is cerebral perfusion pressure calculated ?

Answer 15

mean arterial pressure - intracranial pressure = CPP

Question 16

what should normal CPP be?

Answer 16

80mmHg

Question 17

what should normal MAP be?

Answer 17

90mmHg

Question 18

what should normal ICP be?

Answer 18

5-15mmHg

Question 19

does the brain have a high or low metabolic requirement?

Answer 19

high requirement

Question 20

can the brain use anaerobic respiration ?

Answer 20

no

Question 21

what are the four components that regulate cerebral blood flow?

Answer 21

auto regulation
cerebral metabolism
CO2 and O2
neurohumoral factors

Question 22

what is auto regulation ?

Answer 22

auto regulation is a myogenic mechanism when the smooth muscle constricts

Question 23

when does auto regulation occur ?

Answer 23

when there is an increase in the wall tension

Question 24

does the vessel diameter increase or decrease with increasing cerebral perfusion pressure?

Answer 24

decrease

Question 25

what nucleus do the optic tract pass through before entering the optic radiation ?

Answer 25

lateral geniculate nucleus

Question 26

what nucleus do the optic fibres pass through for the light reflex?

Answer 26

pretectal nucleus

Question 27

what nucleus does the oculomotor nerve pass through to the ciliary ganglia ?

Answer 27

Edinger Westphal nucleus

Question 28

what nerve causes constriction of the pupil?

Answer 28

oculomotor

Question 29

what causes a fixed dilated pupil?

Answer 29

when there is an increased intracranial pressure and the brain herniates through the tenterium cerebelli and compresses the oculomotor nerve and prevents contraction of the sphincter pupillae

Question 30

name three hernias that can occur in the brain ?

Answer 30

Subfalcine herniation medial motor cortex Uncal herniation IIIrd CN, ipsilateral corticospinal tracts Foramen magnum herniation brain stem centres

Question 31

what is it called when the - pulse decreases - resp. rate decreases - diastolic decreases

Answer 31

cushings response

Question 32

why does the pulse and resp. rate decrease with increased intracranial pressure ?

Answer 32

the cardiac centres and resp centres are being compressed

Question 33

does an increase in CO2 partial pressure increase or decrease cerebral blood flow?

Answer 33

increase

Question 34

does an decrease in O2 partial pressure increase or decrease cerebral blood flow?

Answer 34

increase

Question 35

what is the normal CO2 partial pressure ?

Answer 35

35-45mmHg

Question 36

what is the normal O2 partial pressure ?

Answer 36

80-100mmHg

Question 37

when there is increased blood flow what occurs?

Answer 37

cerebral vasodilation and oedema | increased ICP

Question 38

does increased cerebral pressure result in increased or decreased cerebral blood flow ?

Answer 38

decreased blood flow

Question 39

what is hyperventilation ?

Answer 39

very slow deep breathes

Question 40

does hyperventilation help with increased intracranial pressure ?

Answer 40

yes | - will decrease CO2 in blood and hence will reduce vasodilation

Question 41

what drug is given to drain out the brain and reduce the intracranial pressure ?

Answer 41

mannitol

Question 42

what type of drug is mannitol ?

Answer 42

diuretic

Question 43

what instrument can be used to measure the intracranial pressure ?

Answer 43

ICP bolt

Question 44

if the increased intracranial pressure doesn't respond to medical treatment, what can be done ?

Answer 44

craniotomy and evacuation of clot external ventricular drainage decompressive craniectomy

Question 45

what post ICP management may need to be done for a patient ?

Answer 45

- neuropsychology - physio - social work - post traumatic counselling