Neurosensory:Altered Cerebral Function and Increased intracranial pressure (IICP)
Marnie Quick, RN, MSN, CNRN
Etilogy/Patho Altered Cerebral Function: Consciousness
Dynamic state in that it fluctuates Continuum from awareness of self and
environment to unawareness Consciousness to deep coma Caused by:
lesions/injury to the reticular system or cerebral cortex
Metabolic disorders
Altered Cerebral Function: Arousal/cognition (LOC) Patho/assessment
Reticular Activating System (RAS) meshwork of gray cell within brainstem/thalamus. Controls wakefulness, arousal and alertness.
Cerebral cortex outer layer of gray cell bodies of brain. Controls cognition, thought process.
Reticular Activating System (RAS)
Altered Cerebral Function: Assessment of arousal/cognition (LOC)
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
Assessment of arousal/cognition (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
Assessment Arosual/cognition (EOM’S) 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
Assessment arousal/cognition (Motor) Strength, symmetry and ability to move Order from best to worse:
Purposeful Generalized response Posturing- flexion or extension Flaccid
Planter Reflex- Babinski testing Meningeal signs- Brudzinski, nuchal rigidity
Decorticate posturing- abnormal flexion Decerebrate posturing- abnormal extension
Planter Reflex and Babinski testing
Common manifestations/Complications Coma states and brain death Irreversible coma- persistent vegetative state
Does not have functioning cerebral cortex Caused by anoxia or severe brain injury Sleep-wake cycles; chew/swallow/cough, no track
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
Prognosis of individual with altered cerebral functioning
Outcome varies according to underlying cause and pathologic process
The longer the individual unconscious, the longer has absent Doll’s eyes; the poorer the cognitive recovery
Residual mental problem typically outweigh the physical
Altered Cerebral Function Therapeutic Interventions
Diagnostic tests- to R/O & identify cause of altered cerebral function
Medications- Isotonic IV; D50; treat narcotic overdose; fluid/electrolyte replacement; antibiotics
Surgery- to remove cause Other- airway/vent; treat IICP; enteral feeding
Nursing assessment specific to altered cerebral function Terms used to describe (p.1347) Description more important than term Health history- drugs/head injury/metabolic Physical exam- modify as individual cooperation Neuro Vital Signs (p.1299) Glasgow coma scale (p. 1299)
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
Increased Intracranial Pressure (IICP) Normal Brain Monro-Kellie hypothesis Intracranial pressure:5-15 mmHg;60-180cm H2O Cerebral perfusion pressure: MAP-ICP=CPP;
Normal: 80-100 mmHg; minimal blood flow 50; brain death 30 mmHg
Autoregulation- cerebral arterioles change diameter to maintain CBF when ICP rises; need nomal range of MAP to occur; pressure (BP) and chemical (CO2) autoregulation
Increased Intracranial Pressure Pathophysiology of intracranial hypertension
Monro-Kellie hypothesis Cushing reflex- BP and Pulse Brain shifts- herniation syndromes Symptoms progress in relation to these
physiological changes
Increased Intracranial Pressure (IICP) Cerebral edema/hydrocephalus Cerebral edema-
Increases the volume of brain tissue which can cause herniation
Hydrocephalus- Noncommunicating Communicating
Subarachnoid space with arachnoid villi
Increased Intracranial Pressure (IICP) Brain Herniation Syndromes Cingulate herniation Central (transentorial) Uncal (lateral) Infratentorial herniation Extracranial herniation
Brain herniation
Normal brain and Herniation Syndromes
Increased Intracranial Pressure Common manifestations/complications
Result of compression of brain function Level of consciousness most important sign Second- pupil changes as 3rd nerve is compressed Others- p.1355 Speed of IICP how fast cause develops Cushing reflex late sign Complication of IICP is permanent disability,
coma, death
Increased Intracranial Pressure (IICP): Therapeutic Interventions Diagnostic tests- to find cause; monitor hydration/O2 Medications
Osmotic/loop diuretics; antipyretics; anticonvulsants; antiulcer; IV fluids; TPN; vasoactive drugs for MAP; barbiturate coma
Hypothermia Surgery- remove cause; shunt/drain Mechanical ventilation ICP monitoring Other monitors- Jugular venous O2; partial pressure O2 in
brain tissue
Intraventricular and subarachnoid monitoring devices for IICP
Intraventricular drainage system
Increased intracranial pressure (IICP): Nursing assessment specific to IICP
Health history- assess brain involvement Physical exam-
Altered cerebral function assessment Frequency depends on potential IICP Early sign- change in LOC 3rd Cranial nerve compression Papilledema, projectile vomiting, vision changes,
seizures (p. 1355) Late sign- Cushing VS changes– Know!
Increased intracranial pressure (IICP):Pertinent Nursing Problems and Interventions
Ineffective tissue perfusion: cerebral Assess/report sign IICP Adequate airway Promote venous drainage Control environment stimuli Plan nursing care Avoid Valsalva’s maneuver If bone flat out post op- assess Assess external shunts/drains
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