Brain 2

Question 1

The ______ cushions the brain, provides buoyancy, and delivers optimal conditions for neurologic function.

Answer 1

cerebrospinal fluid

Question 2

CSF is located in the

Answer 2

ventricles, cisterns, and subarachnoid space in the brain and spinal cord

Question 3

The total CSF volume is

Answer 3

~150 mL

Question 4

CSF is produced by the

Answer 4

choroid plexus (~30 mL/hr)

Question 5

CSF is absorbed in the

Answer 5

arachnoid villi in the superior sagittal sinus

Question 6

The blood brain barrier separates the

Answer 6

CSF from the plasma

Question 7

The blood brain barrier becomes dysfunctional at sites of

Answer 7

tumor, injury, infection, or ischemia

Question 8

The blood-brain barrier isn’t present at the _______, which explains how some drugs that can’t pass through the BBB can elicit N & V.

Answer 8

chemoreceptor trigger zone

Question 9

The blood brain barrier is poorly developed in the

Answer 9

neonate

Question 10

The specific gravity of CSF is

Answer 10

1.002-1.009

Question 11

CSF pressure is

Answer 11

5-15 mmHg

Question 12

Reabsorption of CSF is dependent on the pressure gradient between

Answer 12

the CSF and venous circulation

Question 13

What is the mnemonic for CSF flow in the brain?

Answer 13

Love My 3 Silly 4 Lorn Magpies

Question 14

Describe the mnemonic for CSF flow in the brain

Answer 14

Lateral ventricles
Monro (foramen)
3rd ventricle
Sylvius (aqueduct)
4th ventricle
Luschka
Magendie

Question 15

_______ is the excessive accumulation of CSF in the brain.

Answer 15

Hydrocephalus

Question 16

What are the two types of hydrocephalus?

Answer 16

obstructive
communicating

Question 17

Describe obstructive hydrocephalus.

Answer 17

Obstruction to CSF flow in the ventricular system (most common)

Question 18

Describe communicating hydrocephalus.

Answer 18

a. decreased CSF absorption by the arachnoid villi (e.g. intracranial hemorrhage)
b. Overproduction of CSF (very rare)

Question 19

Surgical management for either type of hydrocephalus depends on the cause and can include

Answer 19

placing a catheter in the cerebral ventricles to drain CSF
placing a ventriculoatrial shunt (brain to heart)
or ventriculoperitoneal shunt (brain to belly)

Question 20

Where in the brain is the blood-brain barrier NOT present?

Answer 20

chemoreceptor trigger zone
hypothalamus
pineal gland
posterior pituitary gland
choroid plexus

Question 21

The 5 determinants of cerebral blood flow include:

Answer 21

cerebral metabolic rate for oxygen (CMRO2)
cerebral perfusion pressure
PaCO2
PaO2
Venous pressure

Question 22

The brain __________ to protect against blood pressure fluctuations that accompany everyday life.

Answer 22

autoregulates its blood flow

Question 23

Describe the relationship between cerebral blood flow and CMRO2

Answer 23

they are coupled
the greater the need for oxygen, the more blood flow there will be to satisfy this need

Question 24

CMRO2 is decreased by

Answer 24

hypothermia, halogenated anesthetics, propofol, etomidate, and barbiturates

Question 25

CMRO2 is increased by

Answer 25

hyperthermia, seizures, ketamine, and nitrous oxide

Question 26

Cerebral blood flow autoregulates between a cerebral perfusion pressure of

Answer 26

50-150 mmHg in reality, not all patients have such a wide range of autoregulation

Question 27

There's a risk of ________ when CPP is below the lower limit of autoregulation.

Answer 27

hypoperfusion

Question 28

There's a risk of _______ and ________ when CPP is above the upper limit of autoregulation.

Answer 28

cerebral edema & hemorrhage

Question 29

A PaO2 below 50-60 mmHg causes

Answer 29

cerebral vasodilation and increases CBF

Question 30

A high venous pressure reduces _______ and increases ________

Answer 30

cerebral venous drainage; and increases cerebral volume

Question 31

What is the relationship between PaCO2 and CBF?

Answer 31

there is a linear relationship will both go up or down together

Question 32

For every _______ increase in PaCO2, CBF will increase by

Answer 32

1 mmHg; 1-2 mL/100 g brain tissue/min.

Question 33

Maximal cerebral vasoconstriction occurs at a PaCO2 of

Answer 33

25 mmHg

Question 34

Maximal cerebral vasodilation occurs at a PaCO2 of

Answer 34

80-100 mmHg

Question 35

Cerebral blood flow is equal to

Answer 35

Cerebral perfusion pressure/cerebral vascular resistance

Question 36

At a cerebral blood flow of 20 mL/100 g tissue/min we see evidence of

Answer 36

ischemia

Question 37

At a CBF <15 mL/100 g tissue/min, we see

Answer 37

membrane failure and cell death

Question 38

Cerebral perfusion pressure is equal to

Answer 38

MAP-ICP

Question 39

Things that abolish or reduce the effectiveness of autoregulation include

Answer 39

intracranial tumor head trauma volatile anesthetics

Question 40

When PaO2 is above 60 mmHg, cerebral blood flow is

Answer 40

unaffected by PaO2

Question 41

Conditions that impair venous drainage include

Answer 41

jugular compression due to improper head positioning increased intrathoracic pressure secondary to coughing or PEEP vena cava thrombosis vena cava syndrome

Question 42

A fixed and dilated pupil suggests herniation of the: a. cingulate gyrus b. choroid plexus c. temporal uncus d. cerebellar tonsils

Answer 42

C. temporal uncus

Question 43

The most common site of transtentorial herniation is at the

Answer 43

temporal uncus

Question 44

Normal ICP is

Answer 44

5-15 mmHg

Question 45

Intracranial hypertension occurs when ICP exceeds

Answer 45

20 mmHg

Question 46

Signs and symptoms of intracranial hypertension includes

Answer 46

headache, N/V, papilledema, focal neurologic deficit, decreased LOC, seizures, and coma

Question 47

Cushing's triad is composed of

Answer 47

hypertension bradycardia irregular respirations it is a sign of intracranial HTN

Question 48

Describe the Monro-Kellie hypothesis.

Answer 48

the brain, blood, and CSF exist in the confines of the cranium. an increase in one of these components must be countered with a decrease in one or both of the others or an increase in the pressure inside the cranium will occur

Question 49

Herniation at the temporal uncus applies pressure to the

Answer 49

oculomotor nerve (CN 3), making it ischemia; this manifests as a fixed and dilated pupil

Question 50

The gold standard of ICP measurement is

Answer 50

intraventricular catheter

Question 51

ICP measurement is indicated with a GCS score of

Answer 51

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