Flashcards in Acute Intracranial Problems Notes Deck (47)
3 essential volume components of the skull
Cerebrospinal Fluid (CSF)
Occurs at the initial time of injury
Effects of the primary injury that can appear in a few hours to a few days.
Intracranial Pressure (ICP)
Pressure of CSF fluid within the brain.
Factors that influence ICP
The 3 components must stay in a constant volume overall.
Only affects when the skull is closed.
Brain compensates in any component if one component is displaced more than others.
Normal ICP ranges
Cerebral Blood Flow (CBF)
Blood supply given to the brain in any given time period, usually 1 minute.
Automatic adjustment that the brain does to maintain a constant blood flow when arterial BP changes.
Most people have 70mmHg
Critical to maintain MAP when ICP is increased
Cerebral Perfusion Pressure (CPP)
Pressure needed to ensure blood flow to the brain.
How to calculate MAP
How to calculate CPP
CPP=MAP - ICP or
CPP= Flow x Resistance
Factors Affecting Cerebral Blood Flow
Hydrogen ions (H+)
Why is it critical to maintain CBF?
To preserve tissue and minimize secondary injury.
Prevent brainstem compression and brain herniation.
3 Types of Cerebral Edema:
Vasogenic Cerebral Edema
Most common type
Characterized by leakage of large molecules from capillaries into surrounding extracellular space.
Cytotoxic Cerebral Edema
The cell membrane breaks and moves fluids and proteins into cells.
Interstitial Cerebral Edema
Result of hydrocephalus (buildup of brain fluid)
C/M on Increased ICP
Changes in LOC - most reliable indicator of neuro status
Cushing's Triad - MEDICAL EMERGENCY
Compression of Cranial Nerve III - fixed unilateral dilated pupils - MEDICAL EMERGENCY
Blurred vision, diplopia, and extraocular eye movements
Compression of Cranial Nerves II, IV, and VI.
Contralateral hemiparesis or hemiplegia
Decorticate or Decerebrate posturing
Systolic HTN with widening pulse pressure
Bradycardia with bounding peripheral pulses
Which is worse: decorticate or decerebrate
Why do we have to monitor for headache?
Headache may appear benign but that's an early symptom of cerebral edema and increase ICP that can lead to coma and death
2 Major Complications:
Mass lesion in the cerebrum forces brain to herniate downwards
Lateral and downward herniation
Lateral displacement of brain tissue under falx cerebri (dura wall that separate's 2 cerebral hemispheres)
CT and MRI
Transcranial Doppler Studies
Infrascanner - detects life-threatening intracranial bleeding
Lumbar Puncture (LP)