Neuro Exam 1 ( Cerebral Circulation)

Front 1

The cranium is a rigid bony structure containing what?

Back 1

80% brain, water
12% blood
8% CSF

Front 2

What artery supplies the vast majority of blood flow to the brain

Back 2

Internal carotid and basilar arteries (80%)

Front 3

Regional blood flow to the brain is how much?

Back 3

20-80ml/ 100g/min

Front 4

intercranial blood volume at any time is

Back 4

100-150 ml

Front 5

What is the amount of blood flow to the brain?

Back 5

40-50ml/ 100gm/min

Front 6

anterior circulation (80% of cerebral flow) is supplied by what?

Back 6

paired internal carotid arteries

Front 7

Posterior circulation (20%) of cerebral flow is supplied by what?

Back 7

vertebral arteries

Front 8

where do vertebral arteries arise?

Back 8

from subclavian arteries

Front 9

anastomotic circle of willis aries from

Back 9

carotid and vertebral arteries

Front 10

all major cerebral arteries are found where?

Back 10

subarachnoid space

Front 11

if your patient was showing hemiplegia on the contralateral side of the body, greater in the lower than the upper extremities, what arterial origin would you suspect?

Back 11

anterior cerebral artery

Front 12

if your patient was showing signs of aphasia in dominant hemisphere what arterial origin would you suspect.

Back 12

middle cerebral artery

Front 13

if your patient was showing signs of contralateral hemiplegia greater in the upper face and upper extremities than in the lower extremities, sensory loss, or visual loss what arterial origin would you expect

Back 13

Posterior cerebral artery

Front 14

What artery serves the basal ganglia, corpus callosum, medial surface of cerebral hemispheres, superior surface of frontal and parietal lobes

Back 14

anterior cerebral artery

Front 15

What artery serves the frontal lobe, parietal lobe, temporal lobe, (primarily the cortical surfaces)

Back 15

middle cerebral artery

Front 16

what artery supplies part of the diencephalon and temporal lobe, and occipital lobe

Back 16

posterior cerebral artery

Front 17

what lobe of the brain could be affected if you are having difficulty with abstract thinking? what artery supplies this area

Back 17

frontal lobe, anterior cerebral artery

Front 18

What lobe of the brian could be affected if you are having difficulty with somatic sensory things. What artery supplies this?

Back 18

Temporal lobe
Middle cerebral artery

Front 19

What lobe of the brain may be affected if you are having problems with vision? What artery supplies this?

Back 19

occipital, posterior cerebral artery

Front 20

what are your main brain drains?

Back 20

internal jugular

Front 21

anytime you have a situation where the wound is higher than the heart and CVP goes down, what can occur?

Back 21

air can be entrained resulting in a venous air embolus

Front 22

What can a venous air embolus lead too?

Back 22

MI and Stroke

Front 23

your brian receives how much of your cardiac output?

Back 23

15%

Front 24

be able to label circle of Willis

Back 24

carotid, anterior cerebral, anterior communicating, posterior cerebral, posterior inferior cerebellar, middle cerebral, AICA, basilar, verterbrals, posterior comm.

Front 25

The circle of willis allows for what?

Back 25

collateral blood flow

Front 26

at any one time there is around how many ML of CSF

Back 26

150ml

Front 27

CSF is made at a rate of what?

Back 27

30ml/hr or 600-800 ml per day

Front 28

Explain the flow of CSF

Back 28

made it choroid plexus, secreted into the lateral ventricles, through the foramen of monroe, into the 3rd ventricle, down the aqueduct of sylvia, into the 4th ventricle, where is leaves though the 2 foramen of luscchka and 1 foramen of megendie into the subachnoid space by the spinal cord and brain.

Front 29

what absorbs CSF?

Back 29

arachnoidal villi

Front 30

the entire volume of CSF is exchanged how ofteN?

Back 30

3-4 hours

Front 31

hard, tough, non-stretchable membrane, outer dura periosteum of skull

Back 31

Dura Mater

Front 32

What is one space that DOES NOT contain CSF?

Back 32

subdural space

Front 33

Thin, avascular, membranous layer external to pia mater and connected to it by weblike trabeculations

Back 33

arachnoid

Front 34

Spinal anesthesia administered any where between ______ without cord damage.

Back 34

L1-S2

Front 35

Highly vascular membrane that closely approximates spinal cord. Continues beyond termination of spinal cord as FILUM TERMINALE which attaches to coccyx

Back 35

Pia Mater

Front 36

What contains blood supply to the spinal cord?

Back 36

Pia Mater

Front 37

which meninge membrane layer would cause the fastest bleed?

Back 37

Pia, slowest would be arachnoid

Front 38

describe the order of the meninge layers

Back 38

bone...epidural space....dura mater...subdural space (NO CSF)....arachnoid membrane...subarachnoid space (where CSF is)...pia mater (where blood supply is)

Front 39

CSF occurs mainly by secretion in

Back 39

choroid plexus

Front 40

what is the pressure of CSF

Back 40

12mmhg (same as ICp)

Front 41

What can occur if brain tumor , hemorrhage or infection block the aqueduct of sylvius?

Back 41

increased ICP that could lead to hydrocephalus.

Front 42

What is the difference between communicating and non-commnicating hydrocephalus?

Back 42

COmmunicating is a blockage of flow through the subarachnoid spaces or arachnoidal villi where non-communicating there is a block in the aqueduct of sylvius.

Front 43

How are cerebral capillaries different from capillaries that are found in all other parts of the body?

Back 43

they lack "pores" and form tight junctions with overlapping ends with endothelial cells creating an impervious seal.

Front 44

A continuous __________ surrounds the entire circumference of each cerebral capillary

Back 44

basement membrane

Front 45

85% of the outer surface of each capillary is surrounded by __________

Back 45

glial cells

Front 46

for a substance to get to a neuron it maybe have to pass through capillary cells and glial cells, what does this mean?

Back 46

slower arrival of the substance at the neuron

Front 47

what are the five areas outside the BBB

Back 47

pineal gland, neurohypophysis, area postrema, supraoptic crest and subfornical organ

Front 48

what is released by the neurohypophysis (posterior pituitary)

Back 48

ADH and oxytocin

Front 49

when is ADH released and what are its effects on the body?

Back 49

when osmolarity is up > 280...ADH acts on distal segments of the prox tubule and reabsorbs H2O.

Front 50

area postrem is associated with what?

Back 50

N/V

Front 51

what stabilizes the BBB

Back 51

cortisone

Front 52

What is the BBB like is premature babies

Back 52

immature

Front 53

BBB is made more permeable by what?

Back 53

tumors, trauma, hypoxia and severe changes in CO2

Front 54

what is the most important factor of getting IV amnesia drugs to the the GABA A receptors in the brain

Back 54

You want them to be lipid soluble because they will be highly permeable to the brain

Front 55

If an anesthetic drug is highly protein bound, will it cross the BBB?

Back 55

not as readily

Front 56

what is the cerebral metabolic rate of O2

Back 56

3-3.5/mg/100g/min

Front 57

what is the cerebral metabolic rate for glucose

Back 57

4.5/mg/100g/min

Front 58

what is the cerebral metabolic rate of lactate?

Back 58

2.3mM/100g/min

Front 59

What states that the cranial compartment is incompressible and the volume inside the brain is fixed

Back 59

Monroe Kellie Doctorine

Front 60

increased PaCO2 (hypoventilation) leads to what?

Back 60

cerebral dilation and perfusion due to increased H+ ions

Front 61

decreased PaCO2 (hyperventilation) leads to what?

Back 61

less H+ ions and cerebral vasoconstriction.

Front 62

If your PaO2 increases what happens to CBF?

Back 62

decreases

Front 63

If your PaO2 decrease what happens to your CBF

Back 63

increases

Front 64

CPP=

Back 64

MAP-ICP

Front 65

What is normal CPP

Back 65

100mm Hg

Front 66

CBF remains constant despite wide variations in CPP because of what?

Back 66

pressure autoregulation

Front 67

At what CPP do you start to notice EEG changes?

Back 67

50= slowing of EEG
25-40= Flat EEG
<20=irreversibel tissue damage at normothermia

Front 68

auto-regulation functions between what map?

Back 68

50-150

Front 69

what is the main factor affecting CPP in the normal brain?

Back 69

MAP

Front 70

During normal autoregulation of cerebral blood flow, what happens when the MAP is increase? MAP decreased?

Back 70

increased=vasoconstriction, decreasing CBF
decreased=vasodilation, increasing CBF

Front 71

what are the two theories of autoregulation?

Back 71

Myogenic theory for autoregulation and metabolic theory for autoregulation

Front 72

This theory states that autoregulation is an intrinsic response of smooth muscle, stretching of smooth muscle produces vasoconstriction and reduction of BP leads to vasodilation.

Back 72

Myogenic theory for autoregulation

Front 73

Where is the only area in the body where the myogenic theory of autoregulation does not occur?

Back 73

lungs...(hypoxic pulmonary vasoconstriction)

Front 74

If a patient is chronically hypertensive which way will their auto regulation shift?

Back 74

right (keep pt 20% of baseline)

Front 75

This theory states that blood flow is regulated by metabolic activity. So when BP decreases it causes cerebral hypoxia, release of acid metabolites which cause vasodilation

Back 75

metabolic theory of autoregulation

Front 76

if you exceed the upper limit of autoregulation what will occur?

Back 76

autoregulation breakthrough, disruption of the BBB and cerebral edema

Front 77

what profoundly affects Cerebral Blood Flow

Back 77

PaCO2

Front 78

The new research suggest that the low limit for autoregulation should be 70-80 because with MAP of 50-80 why is seen?

Back 78

hypoperfusion of the brain

Front 79

What is the uncoupling effect?

Back 79

when cerebral vessels are dilated increasing CBF but a lower CRMO2 also occurs (anesthetic vapors do this)

Front 80

What causes the uncoupling effect?

Back 80

anesthetic vapors (increase CBF but decrease CMRO2)

Front 81

is the brain capable of anaerobic metabolism?

Back 81

no

Front 82

total lack of O2 to the brain can cause unconsciousness in

Back 82

5-10 seconds

Front 83

under normal conditions almost all of teh energy used by the brain cells is supplies by ______

Back 83

glucose derived from blood
(4.5mg/100g/min)

Front 84

How will a BP taken in the lower extremity indicate the BP in the brain

Back 84

it will be much higher than what the brain BP is seeing

Front 85

for every one inch above or below the organ you are questioning the BP adjust your reading (MAP) by how much?

Back 85

1.85mmhg

Front 86

review effects of arterial blood gas on cerebral blood flow chart

Back 86

PaCO2 varies directly with CBF
PaO2 varies inversely

Front 87

what is the critical level for PaO2?

Back 87

<50

Front 88

If your PaCO2 is 80 what effect does that have on your CBF

Back 88

doubles it

Front 89

if you hyperventilate your patient down to a CO2 of 25 what effect will that have on CBF?

Back 89

cuts CBF in half

Front 90

it is important to maintain constant levels of what ion to maintain neuronal activity

Back 90

H+

Front 91

CO2+H2O=__________ which dissociates into _____. THis leads to what?

Back 91

carbonicacid H+ leading to vasodilation increased CBF and ICP

Front 92

if you hypovevtilate someone this could lead to lactic acidosis....what other responses will you see

Back 92

increased CO2, which causes vasodilation and increased CBF and ICP. Also leads to decreased neuronal activity

Front 93

A patient with chronic hypercapnia will shift the CBF curve which way? what patients will you see this in?

Back 93

to the right.
COPD pts

Front 94

an increase in CBF does not occur until the PaO2 is what?

Back 94

<50mmhg

Front 95

how does a change in HCT effect CBF?

Back 95

no change if HCT 30-50 (normal 45) if HCT is increased it leads to decreased CBF due to viscosity. If HCT is decreased it leads to increased CBF

Front 96

decreased body temp decreased CBF by ____ per degree centigrade drop

Back 96

5%

Front 97

What is the most effective way to protect the brain during both global and focal ischemia?

Back 97

hypothermia

Front 98

the brain uses O2 at a rate of what

Back 98

3,3.5/100g/min

Front 99

where is the metabolic rate the highest?

Back 99

cerebral cortex because that is where most of the neuronal activity is

Front 100

would you use dextrose containing solutions in a patient with transient ischemia?

Back 100

no, hyperglycemia causes greater neuronal damage

Front 101

surpatentorial CSF pressure or pressure in a lateral ventricle or SAS

Back 101

ICP

Front 102

what is the normal ICP

Back 102

10mmhg

Front 103

this position decreases CPP by 15% in the non anesthetizeed patient

Back 103

beach chair

Front 104

pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid, such that, the pressure ratio remains the same

Back 104

Pascals law
change in P=pg(change in h)

Front 105

if a patients MAP is 60 in the arm what can you expect the MAP to be if patient raises there arm 10 in. from the heart

Back 105

10x1.85=18.5 60-18.5=42

Front 106

where can ICP be measured?

Back 106

SAS with a bolt
or in lateral ventricle with a ventriculostomy

Front 107

brains ability to displace blood of CSF to maintain normal ICP

Back 107

buffering capacity

Front 108

label spatial compensation, spatial exhaustion and herniation on the intracranial compliance graft.

Back 108

see notes

Front 109

a tumor in posterior fossa usually produces some degree of brain edema because it obstructs what?

Back 109

Flow of CSF by compressing 4th ventricle

Front 110

If ICP >_____ vicious cycle begins

Back 110

30

Front 111

N2O is ____ time more diffusable than nitrogen. For every 1 N2 you get out ____ N2O go in thus expanding the air

Back 111

30, 32

Front 112

Iso, sevo, des, cause uncoupling effect. what does this mean?

Back 112

decreased CMRO2 but increases CBF and ICP. As blood flow goes up CMRO2 goes down

Front 113

it is important to keep you volatiles at what MAC?

Back 113

less than one (.4-.5)

Front 114

Is N2O a vasoconstrictor or vasodilator?

Back 114

vasodilator

Front 115

what is the anesthestic that causes the coupling effect?

Back 115

barbiturates ( thiopental )
decrease CMRO2 and decreases CBF and ICP

Front 116

what is the number one goal of anesthetic management of neurosurgical patients?

Back 116

prevent hypoxemia

Front 117

it is important to position neuro surgery patients with slightly head up and head in a neutral position so you do no interfere with what?

Back 117

internal jugular drainage

Front 118

free amnesia with a GCS <

Back 118

8

Front 119

this artery supplies 80% of your anterior cord.

Back 119

artery of adamkiewicz

Front 120

used to evaluate the integrity of the spinal cord or nerves during procedures when blood supply to the cord or tissue of the cord is in danger of being damaged

Back 120

SSEP

Front 121

when using SSEP, what waveform would suggest damage in the neuro pathway being monitored?

Back 121

increased latency and decreased amplitude

Front 122

This type of neuro monitoring is least sensitive to anesthetic agents and evaluates CN VIII

Back 122

brainstem auditory evoked potentials

Front 123

this monitor monitors the integrity of CN II and is most sensitive to anesthetic agents

Back 123

visual evoked potential

Front 124

what can not be used with Motor evoked potential monitoring.

Back 124

muscle relaxants and volitiles must be low MAC

Front 125

nerve ______ is lost before cellular integrity is lost.

Back 125

function...this is why neurological monitoring is used.

Front 126

what are the 4A's of anesthesia

Back 126

amnesia, analgesia, akinesia, and autonomic stability

Front 127

what is the region responsible for amnesia

Back 127

cortex

Front 128

what is the region responsible for analgesia

Back 128

thalamus

Front 129

wat is the region responsible for akinesia

Back 129

cord reflex

Front 130

what is the region responsible for autonomic stability

Back 130

endocrine