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

1. Neurosensory:Altered Cerebral Function and Increased Intracranial pressure (IICP) Marnie Quick, RN, MSN, CNRN

2. 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

3. Regulation & maintenance of ICP Normal intracranial pressure • Essential volume components> • Factors influence ICP: • Arterial/venous pressure • Intraabdominal & intrathoracic pressure • Posture • Temperature • Blood gases (CO2) • Normal activities that increase intrathoracic pressure cause rise in ICP

4. 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 increases> IICP • Transient rises in pressure can occur with normal physiological functions

5. Increased Intracranial Pressure (IICP) Cerebral edema/hydrocephalus • Cerebral edema- Increases the volume of brain tissue which can cause herniation • Hydrocephalus- • Noncommunicating • Communicating

6. Subarachnoid space with arachnoid villi

7. Regulation & maintenance of ICP: Measuring intracranial pressure (ICP) • Measured from> • 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 >40 mmHg • Level/duration important!

8. 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 dec> autoregulation fails> CBF decreases • Cerebral Perfusion Pressure (CPP) • Pressure needed to ensure blood flow to brain • CPP=MAP-ICP • Normal 70-100 mmHg; neuronal death <50 mm Hg

9. Cerebral Blood Flow • Pressure changes • Compliance- expandability of brain • Compliance= Volume/pressure • Herination occurs as brain goes greater>lesser pressure • Factors affecting cerebral blood flow • Blood gases (O2,CO2) an H+ • CO2 potent cerebral vasodilator • Cerebral O2 < 50mmHg and >H+ (acidosis) result cerebral vasodilation • Cardiac/respiratory arrest; systemic hemorrhage

10. 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 space> systemic water excess/uncontrolled hydrocephalus

11. ICP:Mechanisms of ICP • Caused by any space occupying lesion; cerebral edema; brain inflammation; metabolic changes • Progression> to right • Herniation Syndromes

12. Herniation Syndromes

13. 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

14. Reticular Activating System (RAS) altered cerebral • 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

15. 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

16. Note cortex in brown; the black lines are 1. association fibers between hemispheres and 2. white tracks going through internal capsule

17. 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

18. Prognosis of an individual in coma • 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

19. Clinical Manifestations of increased ICP

20. 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

21. Complications of IICP: • Inadequate CPP • Herniation Syndromes • Cingulate • Central • Uncal • Infratentorial • Extracranial

22. 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

23. Collaborative Care for increased ICP: Measurement of ICP • Used guide clinical care when risk IICP • GCS<8 • Abnormal CT/MRI • Catheters in picture> • LICOX- brain tissue oxygenation catheter • SjvO2 Jugular cath

24. Collaborative Care for increased ICP: Measurement of ICP

25. Collaborative care for IICP: Intraventricular drainage

26. 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

27. 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

28. Nursing Assessment Specific to ICP: Systematic assessment of unconscious

29. Glasgow coma scale • http://www.unc.edu/~rowlett/units/scales/glasgow.htm

30. Nursing Assessment Specific to ICP: Level of consciousness (most important!) • 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

31. 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

32. Assessment: Extroocular eye movements (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

33. Animations: EOM; Dolls eyes • http://cim.ucdavis.edu/eyes/version15/eyesim.html • http://library.med.utah.edu/kw/animations/hyperbrain/oculo_reflex/oculocephalic2.html

34. 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

35. Planter Reflex and Babinski testing

36. Brudzinski Sign

37. Pertinent Nursing problems/interventions for IICP • Lewis p. 1436-7 NCP 57-1 • Nursing Diagnosis • Ineffective tissue perfusion (cerebral • Decreased intracranial adaptive capacity • Risk for disuse syndrome

38. 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- don’t cluster nursing care • Avoid Valsalva’s maneuver • If bone flat out post op- assess should pulsate/soft • Assess external shunts/drains

39. 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