The Nervous System

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The Nervous System

• Increased ICP
• Head Injury
• Spinal Cord Injury

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Consciousness/Unconsciousness

• ITS ALL RELATIVE!!!

Hyper Alert...AwakeLethargic.Sleeping,
Arousable Unarousable..Coma..Death
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Consciousness

• 2 Components
• Ability for Arousal
• Reticualr Activating System
• Ability for Content
• Can think, act, feel, have purpose
• Disruption in either of these leads to
  Unconsciousness
• 2 Pathological Processes which disrupt Cerebral
  Metabolism
• Cerebral Ischemia-Anoxia
• Cerebral Edema

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Unconsciousness

• Short term to long term
• Fainting to Coma
• In deepest state
• No response to stimuli
• Absence of Corneal, Papillary Reflexes
• No coughing, swallowing (no secretion control)
• No Bowel, Bladder Control
• Little or No Neuron Activity (per EEG)
• Continuum Concept

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Glasgow Coma Scale

• Objective way of assessing and communicating
  findings along this continuum
• 3 indicators
• Opening of eyes
• Verbal Response
• Motor response
• Look for and document BEST response

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Intracranial Pressure

• Skull is a CLOSED BOX
• Enlargement of components within that box can
  cause harm
• Components brain tissue, blood and CSF
• Monroe-Kellie Doctrine
• Factors that influence ICP
• Arterial and Venous pressure
• Intra-abdominal and intra-thoracic pressure
• Posture
• Temperature
• Blood Gases-CO2 Levels

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Regulation, Maintenance and Measurement of ICP

• ICP is the pressure exerted by the total volume
  of the 3 components
• Measured in ventricles, subarachnoid space,
  subdural space, epidural tissue
• Normal pressure 0-15 mm HG
• Sustained pressure gt 15 Abnormal
• Pressures 20-30 mm HG very worrisome
• Pressures gt 30 potentially fatal

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Compensatory Adaptation

• Initial Compensation
• CSF absorption
• Displacement of the CSF into the spinal
  subarachnoid space
• Collapse of cerebral venous and dural sinuses
• Assistive Mechanisms
• Distensibility of the the dura, increase venous
  outflow, decreased CSF production, changes in IC
  blood volume, slight compression of tissue
• Limited Adaptation Ability
• Too much ? in volume over time ? damage

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Cerebral Blood Flow (CBF)

• CBF _at_ of blood in ml passing through 100 gr of
  brain tissue in one minute
• Maintenance of CBF is critical
• brain requires a constant supply of O2 and
  glucose
• Brain uses 20 of the bodys O2 and 25 of its
  glucose

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Autoregulation of CBF

• Automatic alteration in the diameter of the
  cerebral blood vessels to maintain a constant
  blood flow to the brain during changes in
  systemic arterial pressure
• Auto regulation is only effective if MAP is
  between 50 and 150 mm HG
• below 50-vasodilatation maxed out
• above 150-vasoconstriction maxed out
• MAP DP 1/3 pulse pressure

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Autoregulation

• Cerebral perfusion pressure (CPP) is the pressure
  needed to ensure blood flow the the brain (MAP-
  ICP CPP)
• a CPP below 30 mm Hg results in ischemia
• a CPP 30-60 may mean compromised CBF, cellular
  hypoxia
• a CPP between 60-100 will supply adequate CBF
• a CPP gt100 hyperperfusion, ? ICP

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Factors affecting CBF(PaO2, PaCO2, pH)

• PaO2 lt 50 mm Hg-cerebral arteries dilate in
  hopes of ? CBF to raise PO2
• failure causes anaerobic metabolism, ph falls
• ph-- Acidosis causes vasodilatation attempting
  to ? CBF
• PaCO2 -- potent vasodilator relaxes smooth
  muscles , ? CBF
• When autoregulation fails, changes in systemic
  BP, hypoxia, catecholamines increase ICP, left
  unmanaged lead to death

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Cerebral Edema

• A Major Contributor to ? ICP
• 3 types, patients can have more than one type!
• vasogenic most common
• cytotoxic
• interstitial

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Mechanisms of Increased ICP

• Cerebral injury results in hypercapnia, acidosis,
  impaired autoregulation and systemic hypertension
  which promote cerebral edema leading to further
  distortion of brain tissue leading to further
  increased ICP leading to hypoxia and acidosis
  leading to brain stem compression leading to
  herniation leading to respiratory arrest
• (WHOOOO!)

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Clinical Manifestations

• Changes in LOC-
• Dramatic or Subtle ?another continuum
• Cushings Triad - ?SBP, ?HR, Irregular Resp.
• Ocular Signs (sluggish, unequal)
• Changes in Motor Function
• Headaches
• Vomiting

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Diagnostic Studies(beyond H P, VS, X-rays, GCS)

• Computed Tomography CAT Scan
• Magnetic Resonance Imaging
• Angiography
• Positron Emission Tomography
• Transcranial Doppler studies
• CBC, Coagulation profile, Electrolytes, ABGs, CSF
  protein, glucose
• EEG, EKG

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Therapeutics

• TREAT THE CAUSE
• HOB 30, head neutral position
• Intubation, controlled PaCO2 30-35
• BP therapy to maintain Sytstolic Pressure 100-160
• CPP gt 70

• PaO2 gt 100
• Normothermia
• Adequate sedation
• ICP monitoring
• Meds
• osmotic diuretics (Mannitol)
• loop diuretics
• corticosteroids
• hi-dose barbiturates

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Nutritional Management

• Increased ICP is hypermetabolic, hypercatabolic
  state
• Need glucose for fuel
• Malnutrition promotes cerebral edema
• Controversy re hydration status, ? Slightly dry

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Conditions Associated with ? ICP / Cerebral Edema

• Head Injures
• Contusion
• Hemorrhage
• Mass lesions
• tumors
• Abscesses
• Hemorrhage
• Infections

• Vascular Insult
• Infarction
• Anoxic or ischemic episodes
• Toxic Conditions
• Lead, arsenic
• Renal/Liver Failure
• Reyes syndrome
• Near Drowning

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Etiological Factors for Increased ICP

• Hypercapnia (PaCO2 gt 45 mm Hg)
• Hypoxemia (PaO2 lt 60 mm Hg)
• Cerebral vasodilating agents
• Valsalva maneuver
• Body position

• Isometric muscle contraction
• Coughs or sneezes
• Emotional upset
• Noxious stimuli
• Arousal from sleep clustering of activities

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Nursing Interventions

• Respiratory
• secretions
• roto/kinetic bed
• frequent changes
• suction prn
• NG tube
• ABGs
• mechanical ventilation
• Keep C02 ?

• Fluids and Electrolytes
• infusion pumps
• I and O
• daily weights
• labs glucose, K, Na, osmolality
• Diabetes insipidus increase UO
• SIADH decreased UO

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Nursing Interventions

• Body Position
• head up HOB ? 30 degrees
• avoid neck flexion
• slow gentle movement
• Roto-bed, kinetic Bed
• avoid hip flexion
• turn Q 2

• Protection from Injury
• restraints judiciously
• light sedation (Haldol, Ativan)
• ? Seizure precautions
• calm , reassuring voice
• balance between deprivation and overload
• family

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Nursing Interventions

• Psychological Concerns
• Infection
• IVS , other invasive devices
• Urinary Cath
• ICP monitor
• Mechanical Ventilator
• pneumonia

• ICP Monitoring
• epidural sensor
• subdural subarachnoid bolt
• intraventricular cath

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ICP Monitoring Devices
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Head Injury

• Is leading cause of death and disability in
  children and young adults
• Occurs most often in 15-24 year old range
• Men 2X as likely as women
• Approximately 2 million head injured people in US
  per year
• 500,000-will be hospitalized
• 100,00 will die
• 75,000 will have lifelong disabilities
• 2,000 will remain in a persistent vegetative state

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PREVENTION !!!!!

• MVA ( motorcycle! ) injuries
• Falls
• Sport injuries
• These are on the decrease, where as gun shot
  wounds (GSW) are on the increase..

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Descriptive Terms

• Open versus Closed
• Skull broken versus all internal
• Mild/Moderate/ Severe/Critical
• Coup-contra Coup
• 2 plus areas of injury
• Now, use GCS to define, describe
• Terms Focal/Diffuse often used
• Focal-localized damage including a bleed
• Diffuse-widespread damage, anoxia

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Coup- Contra Coup
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Specific Head/Brain Injuries

• Skull Fracture Skull injuries w or w/out any
  actual Brain injury
• Symptoms dependent on location, types
• linear-most common
• basilar ( Battle Sign)-prone to CFS leaks
• depressed-may lead to brain damage
• Complications can include infections, CSF leakage
  and/or hematoma

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Specific Head/Brain Injuries

• Cerebral Concussion Most often minor
• transient, reversible disruption of neural
  activity, LOC
• usually short in duration
• maybe observed in facility overnight or
  discharged with specific instructions
• post-concussion syndrome may last weeks to
  months

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Specific Head/Brain Injuries

• Cerebral Contusion Can be Major
• bruising, usually focal
• may be coup contra coup
• may include brain laceration or tearing
• lacerations may lead to bleeding, hemorrhage
• hemorrhage becomes a space occupying lesion
• symptoms of ? ICP

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Specific Head/Brain Injuries

• Epidural Hematoma Bleeding between the dura and
  the inner surface of the skull
• is an arterial bleed, therefor is considered a
  neurological emergency
• develops rapidly and with pressure
• symptoms May follow the pattern of ? LOC, the
  become lucid, the ? LOC The Talk and Die
  category
• requires immediate surgical evacuation

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Epidural Hematoma
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Specific Head/Brain Injuries

• Subdural Hematomableeding between Dura and
  arachnoid layer
• is usually venous, slower to develop
• symptoms ? LOC, worsening headache, lethargy,
  confusion
• may lead to a chronic hemotoma--months after
  relatively minor head injury
• surgical evacuation

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Subdural Hematoma
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Specific Head/Brain Injuries

• Intracerebral Hematoma within the parenchyma
  itself
• possibly from ruptured vessels
• may be surgically or medically managed
• surgically removed when condition is deteriorating

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Nursing Care

• Very often placed on kinetic bed early on
• Pulmonary support, toilet
• Skin Care
• Body positioning
• Fluid and electrolyte support
• Fluids, Meds,
• I/O

• Nutrition support-often TPN early, move to Tube
  Feeding
• Communication--Remember hearing is last sense to
  leave
• ALWAYS talk to pt. As if they are hearing you
• ICP Monitoring

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Importance of Assessment

• Monitoring for GCS Changes
• Monitoring for subtle changes LOC, level of
  orientation, in strength/weakness, how lucid
  patient is, in Cranial Nerve function..

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Cranial Nerves

• VII-Facial-Facial mvt, taste
• VIII-Acoustic-hearing, balance
• IX-Glossopharyngeal-swallowing, gag
• X-Vagus-PNS, facial sensing,swallowing,
• XI-Spinal accessory-head turning
• XII-Hypoglossal-Tongue

• I-Olfactory-smell
• II-Optic-vision
• III-Oculomotor-pupil constriction
• IV-Trochlear-eye movement
• V- Trigeminal-jaw movement, facial sensing
• VI-Abducens-Lateral eye movement

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How to Remember.

• Fin (Facial)
• And ( Acoustic)
• German (Glossopharyngeal)
• Viewed (Vagus)
• Some (Spinal Accessory)
• Hops (Hypoglossal)

• On (Olfactory)
• Old (Optic)
• Olympus (Ocluomotor)
• Towering (Trochlear)
• Tops (Trigeminal)
• A ( Abducens)

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OUTCOMES of Head Injuries

• Continuum Concept
• Mild/minor to devastating to Death
• Field Care, Critical Care, Restorative-Rehabilitat
  ion Care, Life Adjustment Programs

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Some Concepts to think about..

• Persistent Vegetative State-Brain Stem functions
  are in tact, but no purposeful movement or
  reponses
• may have eye opening, sleep wake cycles but
  thats all
• ethical decisions-Feed? Hydrate? Cost/? Who pays?
  Where cared for? How long?

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Brain Death

• Swelling within brain becomes so severe that
  brain displaces itself, may move side to side, or
  down spinal canal..herniation
• Fatal
• In today's world, however, we can support heart
  and lungs
• Must prove Brain Death
• Issues of organ procurement, donation
• Issues of confidentiality

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Full Cycle

• Flavor of how devastating a Head Injury can be?
• Have any of you experienced this devastation?
  Friends? Family? Patients?
• B.I. Program?
• Back to prevention--Soap box time!!!