Neuro Emergencies: Intracranial HTN Flashcards
What is the fixed internal volume of the intracranial compartment?
1400-1700mL
What is Intracranial HTN?
Elevated pressure w/n the cranial vault
ICP > 22 mmHg
W/o prompt recognition intracranial HTN will lead to what?
Decreased cerebral perfusion
Ischemia
Infarction
Permanent neurologic disability
Herniation
Death
What are the potential causes of Intracranial HTN?
Intracranial mass lesions
Cerebral edema
Hydrocephalus
Idiopathic intracranial HTN
Clinical manifestations of Intracranial HTN include what?
N/V
HA
Altered LOC
Papilledema
Anisocoria
Seizures
Posturing
Cushing’s Triad
What is Cushing’s Triad?
Widening Pulse Pressure
Irregular respiratory pattern
Bradycardia
What are the 6 herniation syndromes?
Uncal
Central
Subfalcine
Transcalvarial
Infratentorial
Tonsillar
Clinical Manifestations of Central Herniation
Diencephalon Anatomic Stage
Respiratory Pattern?
Pupils
Vestibulo-Ocular Reflexes?
Motor Response?
Regular or Cheyne Stokes
Small, reactive
Present, normal
Localized noxious stimuli w/ nonparetic limb; later decorticate posturing
Clinical Manifestations of Central Herniation
Midbrain-upper pons Anatomic Stage
Respiratory Pattern?
Pupils
Vestibulo-Ocular Reflexes?
Motor Response?
Hyperventilation or Cheyne Stokes
Misposition, fixed
Absent or abduction only
Decerebrate or no movement
Clinical Manifestations of Central Herniation
Lower pons-upper medulla Anatomic Stage
Respiratory Pattern?
Pupils
Vestibulo-Ocular Reflexes?
Motor Response?
Ataxic
Midposition, fixed
Absent
no movement or triple flexion response only
Clinical Manifestations of Central Herniation
Medulla Anatomic Stage
Respiratory Pattern?
Pupils
Vestibulo-Ocular Reflexes?
Motor Response?
Irregular or none
Midposition, fixed
Absent
Absent
Indications for ICP monitoring include?
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
ICP monitoring can be done in what 4 ways?
Intraparenchymal
Subarachnoid
Intraventricular
Epidural
ICP Wave Forms
P1 =?
(percussion wave) represents arterial contraction
ICP Wave Forms
P2 =?
(Tidal Wave) represents both vascular and ventricular repercussion of the arterial pulse spread through the brain parenchyma
ICP Wave Forms
P3 =?
(Dicrotic wave) represents aortic valve closure
Elevated ICP treatments include?
Resuscitation
Positioning
Sedation
BP control
Fever Control
Hyperventilation
Osmotic Therapy
Surgical Intervention
Hypothermia
Positioning should be focused on?
HOB Elevated
Head in neutral position
Avoid tight c-collars
Acute Hyperventilation causes?
Cerebral vasoconstriction
Decreased CBF
Decreased CBV
Decreased ICP
Effects are temporary
Should only be used as a temporizing measure
Osmotic Therapy includes what?
What are it’s effects?
Mannitol and hypertonic saline
Reverse clinical herniation, even w/ normal ICP
Reduces ICP
Effects are due to osmotically induced fluid shifts
Osmotic Therapy Hemodynamic effects for both agents include?
Initial increase in blood volume, CO and BP
Osmotic Therapy Hemodynamic effects for Mannitol only?
Rapidly followed by diuresis which can lead to hypovolemia
Mannitol Therapy
Rapidly deteriorating patients require what dose for bolus?
What are the maintenance doses?
Labs required?
1g/kg IV
0.25-1g/kg q6hrs
BMP and serum osmolality q12hrs (baseline required prior to 1st mannitol dose)
Mannitol Therapy
Must calculate the osmolar gap, which is done how?
Difference between serum osmolality and the calculated serum osmolality.
Measured osmolality - calculated osmolality = osmolar gap
Mannitol Therapy
What is the formula for Calculated Osmolality?
= (Nax2) + (BUN/2.8) + (glucose/18)
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?
Equally as effective
Requires Central Access
0.686 ml of 23.4%
Hypertonic Saline - 5%
How to dose it?
What kind of access can it be administered through?
3.2mL/kg
Dose not require a central line for bolus dose
Hypertonic Saline - 3%
How to dose it?
What kind of access can it be administered through?
5.3mL/kg
Dose not require a central line for bolus dose
Potential Complications of Mannitol and Hypertonic Saline include?
Mannitol accumulation in damaged brain
Rebound edema
Renal failure
HS very sclerosing to blood vessels
Potential Surgical Options to help with Intracranial HTN include?
Craniectomy
Craniotomy
Burr hole
EVD placement
Therapeutic Hypothermia
Rationale?
Effect on infarct in animals?
Is it safe with humans?
Invasivenes? requires what?
Effect on ICP?
reduces cerebral metabolism
reduces infarct volume in animals
safe in patients
Very invasive - requires intubation, sedation, paralysis
Reduces ICP
Therapeutic Hypothermia potential complications include?
Coagulation d/o’s
Cardiac arrhythmias
Electrolyte shifts
Myocardial depression
Infections - primarily pneumonia
