Neuro Emergencies: Intracranial HTN

Question 1

What is the fixed internal volume of the intracranial compartment?

Answer 1

1400-1700mL

Question 2

What is Intracranial HTN?

Answer 2

Elevated pressure w/n the cranial vault
ICP > 22 mmHg

Question 3

W/o prompt recognition intracranial HTN will lead to what?

Answer 3

Decreased cerebral perfusion
Ischemia
Infarction
Permanent neurologic disability
Herniation
Death

Question 4

What are the potential causes of Intracranial HTN?

Answer 4

Intracranial mass lesions
Cerebral edema
Hydrocephalus
Idiopathic intracranial HTN

Question 5

Clinical manifestations of Intracranial HTN include what?

Answer 5

N/V
HA
Altered LOC
Papilledema
Anisocoria
Seizures
Posturing
Cushing’s Triad

Question 6

What is Cushing’s Triad?

Answer 6

Widening Pulse Pressure
Irregular respiratory pattern
Bradycardia

Question 7

What are the 6 herniation syndromes?

Answer 7

Uncal
Central
Subfalcine
Transcalvarial
Infratentorial
Tonsillar

Question 8

Clinical Manifestations of Central Herniation
Diencephalon Anatomic Stage
Respiratory Pattern?
Pupils
Vestibulo-Ocular Reflexes?
Motor Response?

Answer 8

Regular or Cheyne Stokes
Small, reactive
Present, normal
Localized noxious stimuli w/ nonparetic limb; later decorticate posturing

Question 9

Clinical Manifestations of Central Herniation
Midbrain-upper pons Anatomic Stage
Respiratory Pattern?
Pupils
Vestibulo-Ocular Reflexes?
Motor Response?

Answer 9

Hyperventilation or Cheyne Stokes
Misposition, fixed
Absent or abduction only
Decerebrate or no movement

Question 10

Clinical Manifestations of Central Herniation
Lower pons-upper medulla Anatomic Stage
Respiratory Pattern?
Pupils
Vestibulo-Ocular Reflexes?
Motor Response?

Answer 10

Ataxic
Midposition, fixed
Absent
no movement or triple flexion response only

Question 11

Clinical Manifestations of Central Herniation
Medulla Anatomic Stage
Respiratory Pattern?
Pupils
Vestibulo-Ocular Reflexes?
Motor Response?

Answer 11

Irregular or none
Midposition, fixed
Absent
Absent

Question 12

Indications for ICP monitoring include?

Answer 12

GCS <9 and w/ an abnormal CT
Comatose pts w/ normal CT scan and two or more of the following
1. Age > 40
2. Posturing
3. SBP < 90 mmHg

Question 13

ICP monitoring can be done in what 4 ways?

Answer 13

Intraparenchymal
Subarachnoid
Intraventricular
Epidural

Question 14

ICP Wave Forms
P1 =?

Answer 14

(percussion wave) represents arterial contraction

Question 15

ICP Wave Forms
P2 =?

Answer 15

(Tidal Wave) represents both vascular and ventricular repercussion of the arterial pulse spread through the brain parenchyma

Question 16

ICP Wave Forms
P3 =?

Answer 16

(Dicrotic wave) represents aortic valve closure

Question 17

Elevated ICP treatments include?

Answer 17

Resuscitation
Positioning
Sedation
BP control
Fever Control
Hyperventilation
Osmotic Therapy
Surgical Intervention
Hypothermia

Question 18

Positioning should be focused on?

Answer 18

HOB Elevated
Head in neutral position
Avoid tight c-collars

Question 19

Acute Hyperventilation causes?

Answer 19

Cerebral vasoconstriction
Decreased CBF
Decreased CBV
Decreased ICP
Effects are temporary
Should only be used as a temporizing measure

Question 20

Osmotic Therapy includes what?
What are it’s effects?

Answer 20

Mannitol and hypertonic saline
Reverse clinical herniation, even w/ normal ICP
Reduces ICP
Effects are due to osmotically induced fluid shifts

Question 21

Osmotic Therapy Hemodynamic effects for both agents include?

Answer 21

Initial increase in blood volume, CO and BP

Question 22

Osmotic Therapy Hemodynamic effects for Mannitol only?

Answer 22

Rapidly followed by diuresis which can lead to hypovolemia

Question 23

Mannitol Therapy
Rapidly deteriorating patients require what dose for bolus?
What are the maintenance doses?
Labs required?

Answer 23

1g/kg IV
0.25-1g/kg q6hrs
BMP and serum osmolality q12hrs (baseline required prior to 1st mannitol dose)

Question 24

Mannitol Therapy
Must calculate the osmolar gap, which is done how?

Answer 24

Difference between serum osmolality and the calculated serum osmolality.
Measured osmolality - calculated osmolality = osmolar gap

Question 25

Mannitol Therapy
What is the formula for Calculated Osmolality?

Answer 25

= (Nax2) + (BUN/2.8) + (glucose/18)

Question 26

Hypertonic Saline - 23.4%
Effectiveness compared to Mannitol?
What kind of access can it be administered through?
How much is equiosmolar to 1g of Mannitol?

Answer 26

Equally as effective
Requires Central Access
0.686 ml of 23.4%

Question 27

Hypertonic Saline - 5%
How to dose it?
What kind of access can it be administered through?

Answer 27

3.2mL/kg
Dose not require a central line for bolus dose

Question 28

Hypertonic Saline - 3%
How to dose it?
What kind of access can it be administered through?

Answer 28

5.3mL/kg
Dose not require a central line for bolus dose

Question 29

Potential Complications of Mannitol and Hypertonic Saline include?

Answer 29

Mannitol accumulation in damaged brain
Rebound edema
Renal failure
HS very sclerosing to blood vessels

Question 30

Potential Surgical Options to help with Intracranial HTN include?

Answer 30

Craniectomy
Craniotomy
Burr hole
EVD placement

Question 31

Therapeutic Hypothermia
Rationale?
Effect on infarct in animals?
Is it safe with humans?
Invasivenes? requires what?
Effect on ICP?

Answer 31

reduces cerebral metabolism
reduces infarct volume in animals
safe in patients
Very invasive - requires intubation, sedation, paralysis
Reduces ICP

Question 32

Therapeutic Hypothermia potential complications include?

Answer 32

Coagulation d/o’s
Cardiac arrhythmias
Electrolyte shifts
Myocardial depression
Infections - primarily pneumonia