Neuroanesthesia Pt. 2 (Exam I) Flashcards

1
Q

How much CSF do we typically have at any given moment?

A

150mls

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2
Q

Where does CSF typically “pool”?

A

Cisterns

Areas where arachnoid membrane and pia mater are further apart.

Don’t need to know specific cisterns.

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3
Q

What is normal CSF pressure for a horizontal patient?

A

10 mmHg

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4
Q

What type of tissue lines the cerebral ventricles?
What does this tissue do?

A

Choroid Plexus (produces CSF)

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5
Q

Which cells excrete CSF?

A

Ependymal (E = Excrete)

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6
Q

What absorbs CSF?

A

Arachnoid Villi (A = Absorb)

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7
Q

What is the path of CSF?

A
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8
Q

In which ventricles is the majority of CSF produced?

A

Lateral Ventricles

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9
Q

CSF Diagram (Flip)

A
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10
Q

What is idiopathic Intracranial HTN?

A

CSF Buildup causing ↑ICP with no obvious reason.

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11
Q

Who is idiopathic intracranial HTN common in?

A
  • Obese women of reproductive age.
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12
Q

What is another name for idiopathic Intracranial HTN?

A

Pseudotumor Cerebri

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13
Q

What is normal ICP?

A

7 - 15 mmHg

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14
Q

When is ICP considered pathologic?

A

> 20 mmHg

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15
Q

Whats a normal CPP?

A

60 - 80 mmHg

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16
Q

What is the critical ischemic threshold for CPP?

A

30 - 40 mmhg

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17
Q

What would the following do to CBF?

  • Hypoxia
  • Hypercarbia
  • ↑ CMRO₂
A

↑CBF

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18
Q

Where does aqueductal stenosis occur?

A

Aqueduct of Sylvius (between 3ʳᵈ & 4th ventricles)

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19
Q

What are the three components of Cushing’s Triad?

A
  • Irregular Respirations
  • Bradycardia
  • Widened pulse pressure
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20
Q

How long might the effects of hyperventilation on PaCO₂ last?

A

6 - 12 hours

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21
Q

What dose of Mannitol is typical in neurosurgery?

A

0.5 - 1 mg/kg

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22
Q

What are the benefits of corticosteroids in neurosurgery?
What are the negatives?

A
  • Pros: Lowers local cerebral swelling (around tumors typically)
  • Cons: May ↑BG and ↓ elasticity of blood vessels
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23
Q

What is parenchyma?

A

Functional Brain Tissue (grey & white matter)

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24
Q

What are potential concerns associated with utilizing hyperventilation to induce brain relaxation?

A
  • Potential ischemia in some areas
  • Brain relaxation temporary (6 - 12 hours)
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25
Q

What dose of decadron is typical for cerebral edema reduction?

A

10mg Q6 hours

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26
Q

What drug is typically paired with mannitol? Why?

A

Furosemide

Prevents rebound effect of cellular swelling from mannitol by inhibiting chloride osmoles.

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27
Q

What is the MOA of levetiracetam?

A

Binds to synaptic vesicle protein 2A (SV2A)

Inhibits release of Ca⁺⁺ by inhibiting this vesicles release.

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28
Q

What is a typical dose of Keppra?

A

500mg BID over 15 min

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29
Q

Which factors are associated with ION?

A
  • Prone position
  • ↓BP
  • ↓ H/H
  • Long surgery
  • Large volume administration
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30
Q

Between LR & NS, which should be used in neurosurgery? Why?

A

NS > LR

NS = 308 mOsm/L
LR = 274 mOsm/L

NS will reduce cerebral edema.

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31
Q

What can occur with Dextran?

A

Dilutional coagulopathy

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32
Q

Does Hypothermia provide brain protection? Is it used?

A

Yes

But, no demonstrated benefits, and can cause arrhythmias & coagulopathy.

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33
Q

What is the recommended BG level for neurosurgery?

A

150 - 200 mg/dL

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34
Q

What is a pressure transducer placed into the subdural space or the brain parenchyma?

A

Subdural bolt

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35
Q

What is a catheter placed in the ventricle allowing for the drainage of CSF?

A

Ventriculostomy

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36
Q

What catheter allows for drainage of CSF but can be inaccurate for measurement of ICP due to the area of its placement?

A

Lumbar subarachnoid catheter

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37
Q

What is normal ScO₂ (cerebral oximetry)?

A

70% (+/- 20 - 30%)

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38
Q

What are SSEPs?

A

Cutaneous electric stimulation peripherally resulting in EEG changes

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39
Q

Are latency readings more reliable with SSEP or MEPs?

A

SSEPs

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40
Q

What are MEPs?

A

Stimuli elicited via electrodes in the head that cause a muscle reaction peripherally.

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41
Q

A __% decrease of amplitude in SSEPs and MEPs is significant.

A

50%

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42
Q

Which type of stroke is more deadly? Hemorrhagic or Embolic?

A

Hemorrhagic

43
Q

What is the most common comorbidity associated with embolic strokes?

A

Cardiovascular disease

Especially Cardiomyopathy (large ventricle = large clot)

44
Q

What is more common, embolic or hemorrhagic strokes?

A

Embolic (80%)

45
Q

tPA is effective if administered within ___ hours of embolic stroke onset.

A

2 hours

46
Q

What is the characteristic symptom of a subarachnoid hemorrhage?

A
  • Thunderclap headache
  • N/V
  • Visual Disturbances
47
Q

How does tPA work?

A

Catalyzes conversion of plasminogen to plasmin

48
Q

Where does blood accumulate in subarachnoid hemorrhages?

A

Between arachnoid space & pia mater

49
Q

What are common causes of intracranial hemorrhage?

A
  • HTN
  • AVM
  • Aneurysm
  • Trauma
  • Coagulopathy
50
Q

Vasospasm is thought to be caused by the breakdown products of ____ and _____.

A

Hgb & NO

51
Q

How is vasospasm typically treated?

A

CCBs
- Nimodipine
- Verapamil
- Nicardipine

52
Q

What therapy is used to prevent vasospams?

A

Triple H Therapy

  • Hypertension (20 - 30 above baseline)
  • Hypervolemia (really euvolemia)
  • Hemodilution (Hct 30ish)
53
Q

What functions do statins have in neurosurgery?

A
  • Improve endothelial function
  • ↓ oxidative stress/ inflammation
54
Q

What function does Mg⁺⁺ have in neurosurgery?

A

Inhibition of Ca⁺⁺ mediated smooth muscle contraction

55
Q

What function does cilostazol have in neurosurgery?

A

Antiplatelet
Vasodilation

56
Q

What type of neursurgery uses MRI/CT imaging and 3-D coordinate system to target precise areas deep in the brain?

A

Stereotactic Neurosurgery

57
Q

What are the old and new ways to do stereotactic neurosurgery?

A
  • Old: Full frame on head preoperatively
  • New: Fiducial markers placed on head
58
Q

What movement disorders are commonly treated with deep brain stimulators?

A
  • Parkinson’s
  • Essential Tremor
  • Dystonia
  • Tourettes
59
Q

What region of the brain is typically targeted with deep brain stimulators

A

Subthalamic Nucleus

60
Q

What is the 1st surgical stage of Deep Brain stimulator implantation?

A

Placement of electrodes under light sedation with stereotactic technique. Patient awake during procedure.

61
Q

What is the 2ⁿᵈ surgical stage of Deep Brain stimulator implantation?

A

GETA, one week after DBS placement with leads tunneled from brain to generator.

62
Q

What additional monitoring device is often used for DBS placement? Why?

A

Precordial Doppler (Risk for VAE)

63
Q

Where are DBS generators typically placed?

A

Typically below clavicle

64
Q

What drug class should be avoided when doing stereotactic ablations for seizures?

A

Benzos (and barbiturates)

65
Q

70 - 95% of epidural hematomas are associated with?

A

Skull Fractures

66
Q

Tear of the _______ artery is common with epidural hematomas.

A

Middle Meningeal Artery

67
Q

A tear of the ______ veins is common with subdural hematomas.

A

Sagittal

68
Q

Between epidural hematomas & subdural hematomas, which can be treated with simple burr hole surgery?

A

Subdural

69
Q

Intubate a neurosurgical trauma patient if the GCS is ___ or less.

A

8

70
Q

What is the target CPP for neuro trauma patients?

A

70 mmHg

71
Q

What is the typical symptom triad of hydrocephalus w/ normal ICP?

A
  • Dementia
  • Gait changes
  • Urinary incontinence
72
Q

Common symptoms of hydrocephalus w/ ↑ICP are…

A
  • N/V
  • LOC changes
  • Papilledema
  • ↓HR
  • HTN
  • Respiratory changes
73
Q

How would a lumbar puncture differ between a hydrocephalus w/ normal ICP and a hydrocephalus w/ elevated ICP?

A

The hydrocephalus w/ elevated ICP will have a high pressure Lumbar Puncture

74
Q

Normal pressure hydrocephalus is a form of ________ hydrocephalus.

A

Communicating

75
Q

What type of hydrocephalus is defined by “CSF can exit the ventricles but can’t be effectively absorbed by arachnoid villi”?

A

Communicating

76
Q

What is the most common cause of non-communicating / obstructive hydrocephalus?

A

Aqueductal stenosis

Narrowing of aqueduct of sylvius between 3ʳᵈ & 4th ventricles.

77
Q

What are the three types of primary brain tumors discussed in lecture?

A
  • Meningioma
  • Glioma
  • Glioblastoma
78
Q

Are meningiomas typically benign or malignant?

A
  • Usually benign
79
Q

What are meningiomas typically found? What is the monitoring consequence of this?

A
  • Usually near sagittal sinus
  • Precordial Doppler for VAE is suggested
80
Q

What are the characteristics of gliomas?

A
  • Non- aggressive typically
  • Surgical resection usually successful
81
Q

What types of cells do gliomas arise from typically?

A
  • Astrocytes
  • Ependymal cells
  • Oligodendrocytes
82
Q

What are the characteristics of glioblastomas?

A
  • Very aggressive
  • Short life expectancy
83
Q

Of glioblastomas, gliomas, and meningiomas, which is most common?

A

Glioblastomas

84
Q

Pituitary tumors typically arise from cells of the _____ pituitary gland and are almost always _______.

A

Anterior : Benign

85
Q

What are the two types of pituitary tumors?

A
  • Microadenomas
  • Macroadenomas
86
Q

What is MEN-1 ?

A

Mutliple Endocrine Neoplasia Type 1

  • Combined pituitary, parathyroid, and pancreatic islet cell tumors.
87
Q

What are the characteristics of microadenomas?

A
  • Hormone-secreting
88
Q

What are the characteristics of macroadenomas?

A
  • Non-hormone secreting
  • Symptoms related to mass effect
89
Q

What functions are associated with prolactin?

A
  • Lactation
  • Infertility
  • Breast development
90
Q

What functions are associated with ACTH?

A
  • Adrenal hyperplasia
91
Q

What issues are associated with excess growth hormone?

A
  • Acromegaly (especially face & hands).
92
Q

What is usually the origin of an acoustic neuroma?

A
  • Benign schwanoma involving CN VIII.
93
Q

What type of evoked potentials are used with acoustic neuroma excision?

A

Auditory Evoked Potentials

94
Q

Bilateral acoustic neuroma formation may occur as part of _________.

A

neurofibromatosis

95
Q

Where do metastatic brain tumors most often originate from?

A

Primary sites like lungs or breast

96
Q

A diagnosis of metastatic brain tumor is more likely when there is one tumor present. T/F?

A

False. Multiple brain tumors = more likely to be metastatic from other bodily region.

97
Q

Are metastatic or primary brain tumors more likely to bleed? Why?

A

Metastatic due to abnormal angiogenesis

98
Q

Can N₂O be utilized for neurosurgeries?

A

Not really, caution with potential for VAE.

99
Q

Retraction of the dura mater over the parietal lobe can induce what?

A

Trigeminal cardiac reflex

100
Q

What is the trigeminal cardiac reflex?

A

Sudden ↓BP & ↓HR

101
Q

What are the cardinal symptoms associated with VAE?

A
  • Mill-Wheel murmur
  • Hemodynamic Instability
  • Sudden drop in EtCO₂
102
Q

Where is ADH synthesized?

A

Supraoptic nuclei of the hypothalamus

103
Q

How is ADH transported from the hypothalamus to the neurohypophysis?

A

Via the supraoptic hypophyseal tract

104
Q

What is the treatment of DI?

A
  • ½ NS
  • Hourly maintenance fluid + ⅔ previous hour UO
  • Desmopressin (if UO > 400 mL/hr)