Transcript Neurosensory: Altered Cerebral Function and Increased Intracranial pressure (IICP)

Neurosensory:
Altered Cerebral Function and Increased
Intracranial pressure (IICP)
Marnie Quick, RN, MSN, CNRN
Normal brain physiology as relates to
increased intracranial pressure
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Brain surrounded by
ridged bone &
meninges
Falx cerebri between
hemispheres
Tentorium cerebelli
between cerebrum
and cerebellum
Regulation & maintenance of ICP
Normal intracranial pressure
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Essential volume
components>
Factors influence ICP:
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Arterial/venous pressure
Intraabdominal &
intrathoracic pressure
Posture
Temperature
Blood gases (CO2)
Normal activities that increase
intrathoracic pressure cause
rise in ICP
Regulation & maintenance of ICP:
Normal Compensatory adaptations
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Monro-Kellie Doctrine
applied- any increase in
one component, cause a
decrease in the other two
Ability to compensate is
limited so when maximal
compensation occurs and
the volume increases>
IICP
Transient rises in
pressure can occur with
normal physiological
functions
Increased Intracranial Pressure (IICP)
Cerebral edema/hydrocephalus
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Cerebral edemaIncreases the volume of
brain tissue which can
cause herniation
Hydrocephalus
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Noncommunicating
Communicating
Subarachnoid space with arachnoid villi
Regulation & maintenance of ICP:
Measuring intracranial pressure (ICP)
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Measured from>
Normal pressure brain
0-15 mm Hg by
intracranial monitor
Lumbar pressure 100200 mm H2O (by LP)
Clinical symptoms
appear 20-25 mm Hg;
severe ICP >40 mmHg
Level/duration important!
Cerebral Blood Flow
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Autoregulation
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Ability of the brain to regulate own blood flow
Automatic alteration in diameter of cerebral blood
vessels to maintain constant blood flow to the brain
despite changes in systemic arterial BP
Must have at least 50 mm Hg of MAP to work
As CPP dec> autoregulation fails> CBF decreases
Cerebral Perfusion Pressure (CPP)
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Pressure needed to ensure blood flow to brain
CPP=MAP-ICP
Normal 70-100 mmHg; neuronal death <50 mm Hg
Cerebral Blood Flow
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Pressure changes
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Compliance- expandability of brain
Compliance= Volume/pressure
Herination occurs as brain goes greater>lesser
pressure
Factors affecting cerebral blood flow
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Blood gases (O2,CO2) an H+
CO2 potent cerebral vasodilator
Cerebral O2 < 50mmHg and >H+ (acidosis) result
cerebral vasodilation
Cardiac/respiratory arrest; systemic hemorrhage
ICP: Cerebral edema
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Increase fluid extravascular space Cerebral edema
Causes: Mass lesions; head inj; brain surgery;
cerebral infections; vascular insult;
toxic/metabolic conditions
Vasogenic: Most common. Fluid in white matter
Cytotoxic: Fluid in gray matter
Interstitial: Fluid in extracellular space> systemic
water excess/uncontrolled hydrocephalus
ICP:
Mechanisms of ICP
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Caused by any space
occupying lesion;
cerebral edema; brain
inflammation;
metabolic changes
Progression> to right
Herniation
Syndromes
Herniation Syndromes
Normal brain as it relates to:
altered cerebral function
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Consciousness is a dynamic state that can
fluctuate between awareness of self and
environment to unawareness (coma)
Etiology of altered cerebral function
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Lesions or injury to RAS &/or cerebral cortex
Metabolic disorders
Brain lesions (tumor/bleed); cardiac (MI);
resp; kidney; DM; fluid electrolyte imbal
Reticular Activating System
(RAS) altered cerebral
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Reticular formation
meshwork of gray cells
within the
brainstem>thalamus
Controls wakefulness,
arousal and alertness
Injury to RAS with intact
cortex results in diff with
arousal which> assess
cognitive function diff
Cerebral Cortex &
altered cerebral function
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Outer layer of gray cell
bodies
Controls cognition;
thought processes
Widespread injury with
intact RAS, may respond
to stimuli, but not with
understanding
Sleep-wake cycles
Note cortex in brown; the black lines are 1. association fibers
between hemispheres and 2. white tracks going through
internal capsule
Coma states and brain death
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Coma: not awake and not aware
Persistent Vegetative state:
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Minimally Conscious State: awake- inconsistently aware
Locked-in Syndrome (not true coma:
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Does not have functioning cerebral cortex, awake- not aware
Caused by anoxia or severe brain injury
Sleep-wake cycles; chew/swallow/cough, no tracking with eyes
Functioning RAS/cortex; pons level interference
Aware, communicate with eyes
Brain death:
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Loss of all brain function- flat EEG, no blood flow
Prognosis of an individual in coma
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Outcomes vary-cause & pathologic process
Longer individual unconscious, loner has absent Doll’s
eyes, the poorer the cognitive recovery
Residual mental problems outweigh physical problems
Glasgow coma scale at 24 hrs is a good indication of
prognosis
Individual more concerned with cognitive and memory
problems; family emotional/personality changes
Management of coma includes identifying cause,
preserving function and preventing deterioration.
Requires total body system maintenance
Clinical Manifestations of increased ICP
Clinical manifestations of IICP
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Result of compression of brain function
Level of consciousness most important sign
Second- pupil changes as 3rd nerve is
compressed
Speed of IICP how fast cause develops
Cushing reflex late sign
Complication of IICP is permanent
disability, coma, death
Complications of IICP:
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Inadequate CPP
Herniation
Syndromes
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Cingulate
Central
Uncal
Infratentorial
Extracranial
Collaborative Care for increased ICP:
Diagnostic tests
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to identify underlying cause; monitor hydration, O2
X-ray- spine/head
CT/MRI
Cerebral angiography
EEG/EKG
Brain tissue oxygenation measurement
ICP measurement
Transcranial doppler studies
Evoked potentials
PET
Lab studies- blood; CSF
Collaborative Care for increased ICP:
Measurement of ICP
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Used guide clinical
care when risk IICP
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GCS<8
Abnormal CT/MRI
Catheters in picture>
LICOX- brain tissue
oxygenation catheter
SjvO2 Jugular cath
Collaborative Care for increased ICP:
Measurement of ICP
Collaborative care for IICP:
Intraventricular drainage
Collaborative care of IICP:
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Adequate O2; ABG analysis; may require
ventilator
HOB 30 degrees; head and legs in neutral
position
Keep blood glucose within normal range
Hypothermia to decrease metabolic rate
Fluid balance- normovolemic IV NS; check
osmoality
Nutritional therapy- hypermetabolic state- NG
nutrition as soon as gut functioning
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Drug therapy
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Mannitol (Osmitrol) osmostic diuretic
Corticosteriods- control vasogenic edema with
tumors/abscesses
High-dose barbiturates (coma) dec metabolic rate
Antiseizure- phenytoin
H2 receptor antagonist or proton pump inhibitors
Surgery
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To remove space occupying lesions- brain tumor,
abscesses, hematoma
Craniectomy- bone flap
Nursing Assessment Specific to ICP:
Systematic assessment of unconscious
Glasgow coma scale
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http://www.unc.edu/~rowlett/units/scales/glasgow
.htm
Nursing Assessment Specific to ICP:
Level of consciousness (most important!)
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Observe individual’s behavior, call name
Verbal response to person/place/time/event
If unable- how responds to commands
If unable- how responds to central pain stimuli
Description of confusion>coma is more important
than terms
Nursing Assessment Specific to ICP:
Respiratory and pupillary light reflex
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Respiratory- changes
occur as brainstem is
being compressed
Pupillary light reflexSensory: CN 2 Motor: 3
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Note pupil size; darken
room; shine light in and
note reaction and size
Direct/consensual
Assessment: Extroocular eye movements
(EOM’S)
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Eye movement- CN 3,4,6
In COMA- test EOM’s
Oculocephalic reflex
Doll’s eyes- Sensory- CN
8; Motor- CN 3,4,6
Good Dolls eyes: eyes
move in opposite
direction of head
movement
Bad/negative Dolls eyes:
eyes do not move head
turned
Animations: EOM; Dolls eyes
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http://cim.ucdavis.edu/eyes/version15/eyesi
m.html
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http://library.med.utah.edu/kw/animations/
hyperbrain/oculo_reflex/oculocephalic2.ht
ml
Assessment: Motor
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Strength, symmetry and ability
to move
Order from best to worse:
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Purposeful
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Generalized response
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Posturing- abnormal
flexion or extension
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Flaccid
Planter Reflex- Babinski
testing
Meningeal signs- Brudzinski,
nuchal rigidity
Planter Reflex and Babinski testing
Brudzinski Sign
Pertinent Nursing problems/interventions
for IICP
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Lewis p. 1479/80 NCP 57-1
Nursing Diagnosis
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P
Ineffective tissue perfusion (cerebral
Decreased intracranial adaptive capacity
Risk for disuse syndrome
Increased intracranial pressure (IICP):
Pertinent Nursing Problems and Interventions
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Ineffective tissue perfusion: cerebral
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Assess/report sign IICP
Adequate airway
Promote venous drainage- HOB 30 no flex neck/knee
Control environment stimuli
Plan nursing care- don’t cluster nursing care
Avoid Valsalva’s maneuver
If bone flat out post op- assess should pulsate/soft
Assess external shunts/drains
Altered Cerebral Functioning:
Pertinent Nursing problems
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Ineffective airway
Risk for aspiration
Risk for impaired skin integrity
Impaired physical mobility
Risk for imbalanced nurtition
Ineffective coping- Family
Home care