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

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NeurosensoryAltered Cerebral Function and
Increased Intracranial pressure (IICP)

• Marnie Quick, RN, MSN, CNRN

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Normal brain physiology as relates to
increased intracranial pressure

• Brain surrounded by ridged bone meninges
• Falx cerebri between hemispheres
• Tentorium cerebelli between cerebrum and
  cerebellum

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Regulation maintenance of ICP
Normal intracranial pressure

• Essential volume componentsgt
• Factors influence ICP
• Arterial/venous pressure
• Intraabdominal intrathoracic pressure
• Posture
• Temperature
• Blood gases (CO2)
• Normal activities that increase intrathoracic
  pressure cause rise in ICP

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Regulation maintenance of ICP Normal
Compensatory adaptations

• 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 increasesgt
  IICP
• Transient rises in pressure can occur with normal
  physiological functions

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Increased Intracranial Pressure (IICP)
Cerebral edema/hydrocephalus

• Cerebral edema- Increases the volume of brain
  tissue which can cause herniation
• Hydrocephalus-
• Noncommunicating
• Communicating

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Subarachnoid space with arachnoid villi
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Regulation maintenance of ICP Measuring
intracranial pressure (ICP)

• Measured fromgt
• Normal pressure brain 0-15 mm Hg by
  intracranial monitor
• Lumbar pressure 100-200 mm H2O (by LP)
• Clinical symptoms appear 20-25 mm Hg severe ICP
  gt40 mmHg
• Level/duration important!

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Cerebral Blood Flow

• Autoregulation-
• 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 decgt autoregulation failsgt CBF decreases
• Cerebral Perfusion Pressure (CPP)
• Pressure needed to ensure blood flow to brain
• CPPMAP-ICP
• Normal 70-100 mmHg neuronal death lt50 mm Hg

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Cerebral Blood Flow

• Pressure changes
• Compliance- expandability of brain
• Compliance Volume/pressure
• Herination occurs as brain goes greatergtlesser
  pressure
• Factors affecting cerebral blood flow
• Blood gases (O2,CO2) an H
• CO2 potent cerebral vasodilator
• Cerebral O2 lt 50mmHg and gtH (acidosis) result
  cerebral vasodilation
• Cardiac/respiratory arrest systemic hemorrhage

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ICP Cerebral edema

• 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 spacegt
  systemic water excess/uncontrolled hydrocephalus

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ICPMechanisms of ICP

• Caused by any space occupying lesion cerebral
  edema brain inflammation metabolic changes
• Progressiongt to right
• Herniation Syndromes

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Herniation Syndromes
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Normal brain as it relates to
altered cerebral function

• Consciousness is a dynamic state that can
  fluctuate between awareness of self and
  environment to unawareness (coma)
• Etiology of altered cerebral function
• Lesions or injury to RAS /or cerebral cortex
• Metabolic disorders
• Brain lesions (tumor/bleed) cardiac (MI) resp
  kidney DM fluid electrolyte imbal

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Reticular Activating System (RAS) altered
cerebral

• Reticular formation meshwork of gray cells within
  the brainstemgtthalamus
• Controls wakefulness, arousal and alertness
• Injury to RAS with intact cortex results in diff
  with arousal whichgt assess cognitive function diff

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Cerebral Cortex altered cerebral function

• 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

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Note cortex in brown the black lines are 1.
association fibers between hemispheres and 2.
white tracks going through internal capsule
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Coma states and brain death

• Coma not awake and not aware
• Persistent Vegetative state
• 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
• Minimally Conscious State awake- inconsistently
  aware
• Locked-in Syndrome (not true coma
• Functioning RAS/cortex pons level interference
• Aware, communicate with eyes
• Brain death
• Loss of all brain function- flat EEG, no blood
  flow

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Prognosis of an individual in coma

• Outcomes vary-cause pathologic process
• Longer individual unconscious, loner has absent
  Dolls 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

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Clinical Manifestations of increased ICP
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Clinical manifestations of IICP

• 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

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Complications of IICP

• Inadequate CPP
• Herniation Syndromes
• Cingulate
• Central
• Uncal
• Infratentorial
• Extracranial

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Collaborative Care for increased ICP
Diagnostic tests

• 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

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Collaborative Care for increased ICP
Measurement of ICP

• Used guide clinical care when risk IICP
• GCSlt8
• Abnormal CT/MRI
• Catheters in picturegt
• LICOX- brain tissue oxygenation catheter
• SjvO2 Jugular cath

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Collaborative Care for increased ICP
Measurement of ICP
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Collaborative care for IICP
Intraventricular drainage
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Collaborative care of IICP

• 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
• 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
• To remove space occupying lesions- brain tumor,
  abscesses, hematoma
• Craniectomy- bone flap

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Nursing Assessment Specific to ICP
Systematic assessment of unconscious
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Glasgow coma scale

• http//www.unc.edu/rowlett/units/scales/glasgow.h
  tm

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Nursing Assessment Specific to ICP Level
of consciousness (most important!)

• Observe individuals 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 confusiongtcoma is more important
  than terms

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Nursing Assessment Specific to ICP
Respiratory and pupillary light reflex

• Respiratory- changes occur as brainstem is being
  compressed
• Pupillary light reflex- Sensory CN 2 Motor 3
• Note pupil size darken room shine light in and
  note reaction and size
• Direct/consensual

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Assessment Extroocular eye movements
(EOMS)

• Eye movement- CN 3,4,6
• In COMA- test EOMs Oculocephalic reflex
• Dolls 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

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Animations EOM Dolls eyes

• http//cim.ucdavis.edu/eyes/version15/eyesim.html
• http//library.med.utah.edu/kw/animations/hyperbra
  in/oculo_reflex/oculocephalic2.html

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Assessment Motor

• Strength, symmetry and ability to move
• Order from best to worse
• Purposeful
• Generalized response
• Posturing- abnormal flexion or extension
• Flaccid
• Planter Reflex- Babinski testing
• Meningeal signs- Brudzinski, nuchal rigidity

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Planter Reflex and Babinski testing
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Brudzinski Sign
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Pertinent Nursing problems/interventions for IICP

• Lewis p. 1479/80 NCP 57-1
• Nursing Diagnosis
• Ineffective tissue perfusion (cerebral
• Decreased intracranial adaptive capacity
• Risk for disuse syndrome
• P

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Increased intracranial pressure (IICP)Pertinent
Nursing Problems and Interventions

• Ineffective tissue perfusion cerebral
• Assess/report sign IICP
• Adequate airway
• Promote venous drainage- HOB 30 no flex neck/knee
• Control environment stimuli
• Plan nursing care- dont cluster nursing care
• Avoid Valsalvas maneuver
• If bone flat out post op- assess should
  pulsate/soft
• Assess external shunts/drains

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Altered Cerebral Functioning
Pertinent Nursing problems

• Ineffective airway
• Risk for aspiration
• Risk for impaired skin integrity
• Impaired physical mobility
• Risk for imbalanced nurtition
• Ineffective coping- Family
• Home care