Intracranial Pressure - Exam 6 Flashcards Preview

SEMESTER FOUR!! Nursing 214 > Intracranial Pressure - Exam 6 > Flashcards

Flashcards in Intracranial Pressure - Exam 6 Deck (46):
1

What is blood brain barrier?

Physiologic barrier between blood capillaries and brain tissue

2

What is the monroe-kellie docterine?

Within closed space (skull) there must be a constant volume of 3 components within the skull: brain tissue, blood, CSF. If this fails, increase ICP results

 

The adult skull is a rigid box containing brain tissue, cerebral spinal fluid and blood. When the volume or amount of one of these substances changes there must be changes in the others to compensate.

3

What is cerebral perfusion pressure?

CPP=MAP-ICP

Normal = 60-100

If ICP is too high, patient's brain will herniate through formen magnum. If CPP is too low, patient will suffer anoxic brain injury. MAP must be enough to keep perfusing, even with increased ICP.

 

The amount of pressure needed to adequate perfuse brain tissue (provides adequate O2 and nutrients, removes wastes)

4

What is cerebral edema?

Swelling/edema of the brain

Fluid volume overload, hyponatremia

3 types: vasogenic, interstitial, cytotoxic

5

What is brain (tentorial) herniation?

The brain presses into places it should not

6

What is ventriculostomy/intracranial pressure monitoring?

  1. To drain CSF out
  2. Measure ICP
  3. Instill intraventricular medication

7

mannitol (Osmitrol)

Classification: diuretic

Mechanism of action: plasma expander, osmotic response. Plasma expanding effect lowers HCT and blood viscosity and increases CBF and O2 delivery. The osmotic gradient created moves fluid from tissue into blood vessels

Use: cerebral edema, increased intraocular pressure

Side/Adverse effects: Increased UO, tachycardia, seizures, rebound increased ICP

Nursing Implications:

  1. I/O
  2. BP
  3. Electrolytes (K, NaCl)
  4. BUN/Cr
  5. Neuro checks
  6. Seizure precautions
  7. Do not use if patient has kidney disease
  8. Often given with lasix
  9. Osmolality

8

dexamethasone (Decadron)

Classification: Corticosteroid

Mechanism of action: Decreases inflammation by controlling vasogenic edema surrounding tumors/abscesses. Not recommended for use in head injury due to increased mortality risk.

Use: brain tumors (edema around tumor), inflammation, cerebral edema

Side/adverse effects: poor wound healing, increased risk of infection, hyperglycemia, GI hemorrhage, mood changes, psychosis, insomnia, seizures, osetoporosis

Nursing Implications:

  1. I/O
  2. Monitor for s/sx of increasing edema
  3. Daily weights
  4. S/sx of infection
  5. Mental status changes
  6. BG should be monitored

9

What breathing patterns may be seen with increased ICP?

  1. Cheyne-Stokes
  2. Central neurogenic hyperventilation
  3. Apneustic breathing
  4. Cluster breathing
  5. Ataxic breathing

10

What is cheyne-stokes breathing?

Cycles of hyperventilation and apnea

Location: bilateral hemispheric disease of metabolic brain dysfunction

11

What is central neurogenic hyperventilation?

Sustained, regular rapid and deep breathing

Location: brainstem between lower midbrain and upper pons

12

What is apneustic breathing?

Prolonged inspiratory phase or pauses alternating with expiratory pauses

Location: mid or lower pons

13

What is cluster breathing?

Clusters of breaths follow each other with irregular pauses between

Location: medulla or lower pons

14

What is ataxic breathing?

Completely irregular with some breaths deep and some shallow. Random, irregular pauses, slow rate.

Location: reticular formation of the medulla

15

Risk for ineffective cerebral tissue perfusion

Risk for decrease in cerebral tissue circulation

Defining Characteristics:

  1. Reduction of venous/arterial blood flow and cerebral edema as evidenced by
    1. CPP <60mm Hg
    2. GCS <8
    3. Altered mental status
    4. Behavioral changes
    5. Motor dysfunction

Nursing Interventions:

  1. Neuro checks
    1. GCS
    2. NIH stroke score
    3. Papillary response
    4. Montor function
    5. Aphasia
  2. VS
  3. I/O
  4. Electrolytes
  5. O2 sat
  6. Fall precautions
  7. Seizure precautions
  8. Monitor ICP
  9. Notify MD of any changes
  10. End tidal CO2
  11. Calculate CPP
  12. HTN with volume expansion, positive intotropic or vasoconstrictive agents to maintain hemodynamic parameters and optimize CPP
  13. Neurological status to evaluate O2 of brain
  14. Normovolemia and assess effects of diuretics/corticosteroids
  15. Safety measures

16

Decrease intracranial adaptive capacity

Intracranial fluid dynamic mechanism that normally compensates for increase in intracranial volumes are compromised, resulting in repeated disproportionate increase in ICP in response to a variety of noxious and nonnoxious stimuli

Defining characteristics:

  • Decreased cerebral perfusion
  • Sustained ICP
  • Changes in ICP
  • Increased BP
  • Decreased HR
  • Decreased RR

Nursing Interventions:

  1. Neuro checks
  2. VS
  3. Prevent hyperthermia (sometimes induced hypothermia)
  4. Decrease environmental stimuli
  5. HOB at 30 degrees to improve venous drainage
  6. Suctioning as needed for shortest amount of time possible
  7. Glycemic control (CO2 increased = vasodilation)
  8. Maintain normal fluid volume
  9. Sedate patient
  10. Consider hypothermia as decreased ICP
  11. Manage pain

17

What is a major objective when taking care of a patient with ICP or potential for increased ICP?

Protect the patient at risk from sudden icnreases in intracranial pressure

18

What should you do regarding baseline neurological signs?

Assess baseline neurological signs with periodic reassessment and comparison to previous findings. Assess LOC, pupillary size and reaction to light, eye movement, and motor/sensory function.

Subtle changes in neurological signs can indicate deterioration or improvement in the neurological status. These changes can only be detected by frequent monitoring and comparison with previous findings.

19

What should you do regarding vital signs?

Neurological assessment includes routine monitoring of VS. Compare findings with previous recordings to note trends.

Intracranial decompensation is noted by decreased HR, increased BP, widening pulse pressure and irregular respiratory patter (Cushing's triad). It is generally accepted that VS correlate poorly with early neurological deterioration. Changes in VS are a late indicator of increased ICP.

20

What should you do regarding temperature?

The temperature should be monitored and treatment initiated for elevations.

Elevated temperature, increased oxygen consumption, and increased production of by-products of metabolism aggravate increased ICP.

21

What should you do regarding respiratory assessment?

Perform a complete respiratory assessment

Indicates the patency of the airway, adequacy of respirations, and proper lung expansion

22

What should you do regarding blood gases?

Monitor blood gases. PaO2 below 85mm Hg is considered low. Maintain PaCO2 per provider order (usually between 30-40 mm Hg).

Decreased PaCO2 constricts cerebral blood vessels which will decrease cerebral edema and reduce ICP. Unfortunately, prolonged cerebral vasoconstriction has the potential to impair cerebral tissue perfusion and lead to cerebral ischemia. Impaired cerebral blood flow decreased the availability of glucose and oxygen to the cerebral tissues and can lead to  cerebral anoxia.

23

What should you do regarding oxygen?

Administer oxygen at the ordered percentage or titrate O2 to keep spO2 within prescribed parameters

If oxygen concentration is low, oxygen administration may be instituted or increased. Adequate oxygen is needed to meet metabolic demands.

24

What should you do regarding suction?

Suction only when necessary for no more than 10 seconds per catheter insertion.

Time limit prevents the buildup of carbon dioxide which is a potent cerebral vasodilator able to aggravate increased intracranial pressure.

25

What should you do regarding bedrest/activity level?

Maintain patient on bedrest or activity level as ordered by MD. Head elevation will vary depending on provider order (usually 30 degrees) and the patient's MAP. Avoid prone poistion, exaggerated neck flexion, and extreme hip flexion of 90 degrees or greater.

HOB elevation of 30 degrees facilitates cerebral venous return. Neck flexion may interfere with venous return from the brain. Extreme hip flexion potentially increases intraabdominal and intrathoracic pressure which intereferes with cerebral venous return. Elevating the HOB may decrease CPP by lowering SBP. Evaluate the effect of HOB elevation on both CPP and ICP.

26

What should you do regarding moving/turning patient?

Patients able to follow simple directions should be instructed to exhale upon turning or moving. Assist patient in moving up in bed. Do not ask the patient to push with the heels. Do not allow patient to push or pull with his arms or push against the footboard. Do not encourage or suggest isometric exercises for your alert patient. Passive range of motion exercises should be incorporated into the nursing care plan.

Prevents initiation of valsalva maneuver

27

What are common medications used and their anticipated therapeutic effects?

  1. Osmotic diuretics (mannitol, lasix)
    1. Decreases cerebral edema and ICP
  2. Dexamethasone (Decadron) PO, IM, or IV
    1. Reduces inflammation and cerebral edema
  3. Phenytoin (Dilantin) PO or IV
    1. Prevents seizure activity
  4. Colace (Docusate sodium) PO
    1. Prevents straining at stool
  5. Protonix (pantoprazole) PO or IV (or other PPI/H2 blocker)
    1. Prevents GI irritation, stimulation of gastric secretions
  6. Acetaminophen (Tylenol) PO or PR
    1. Controls elevated temperature thus decreasing metabolic demands
  7. Prophylactic broad-spectrum antibiotics may be ordered if the patient has external ventricular drainage or continous intracranial monitoring
    1. PRevents infection
  8. Hypertonic saline (3% saline)
    1. Raises the osmolality of the extracellular fluid in the brain, thus decreasing cerebral water content

28

What should you do regarding sedative/pain medications?

Sedative and pain medications are given. Patient may be placed in a "drug induced coma."

Keeps metabolic demand and cerebral O2 consumption down to allow for healing and prevents spikes in BP. However, changes in neurologic state may be masked as most sedatives potentially alter neurologic status. Patients may have a "sedation vacation" regularly to permit assessment of neurologic status.

29

How should the nurse plan nursing care activities?

Plan nursing care so that those activities that are apt to produce spikes in intracranial pressure are not clustered together.

Contrary to what has been considered good organizational skills in patient management, it is best no to cluster patient care activities. Individually, these activities may not cause a large increase in ICP but performed together rises in ICP can be expected.

30

What should you do regarding seizure precautions?

Maintain seizure precautions.

Prevents injury to patient should a seizure occur.

31

What should you do regarding the environment?

Maintain a calm approach and calm quiet environment with minimal noise. Limit interruptions.

Decreasing patient stimulus decreases the patient's metabolic demand and ICP.

32

What should you do regarding patient family teaching?

Teach the family to limit patient stimulation.

Family members frequently stimulate thier loved one attempting to get them to return to prior level of awareness, however, this increases the patient's metabolic demand and ICP.

33

What should be done regarding external ventricular drainage?

With external ventriculostomy drainage (EVD), the elevation of the head of the bed will depend on the physician. The nurse should know how high the drainage collection container should be kept above the level of insertion.

Placing the collection container at too low a level provides for a too-rapid removal of CSF drainage and can lead to brain herniation. Placing the collection container at too high a level will prevent CSF drainage from occuring.

Maintain integrity and sterility of ventriculostomy drain and set up to prevent infection.

Drainage of CSF VIA the ventriculostomy per provider order. Drainage of CSF reduces ICP

34

What should you do regarding urinary output?

Monitor urinary output. Periodic specific gravity of urine may be ordered.

Indicates the amount of diuresis or urinary concentration. Damage to the pituitary may result in DI or SIADH and would be evidenced by a change in specific gravity and a change in output.

35

What should be done regarding stool softeners?

Stool softeners should be administered. Avoid enemas or straining at stool.

The valsalva maneuver is itiated by straining at stool or by an enema and must be avoided

36

What is traumatic brain injury (TBI)?

Term used as an example of a disease process that causes increased intracranial pressure. TBI is the leading cause of death in children and greater than 50,000 fatalities are seen in adults annually.

37

What are the two types of brain trauma?

  1. 1st degree injury - occurs at time of trauma
    1. blunt injury
    2. coup-contrecoup injury
    3. Direct injury to the brain (may be irreversible)
  2. 2nd degree injury - occurs as a result of injury
    1. Edema
    2. Increased ICP
    3. Hypoxia
    4. Hypotension
    5. chemical changes in the brain
    6. Hypo/hyper capnia
    7. Goal of nursing interventions are to prevent these sequale known as secondary injury

38

Adult CPP

60 mm Hg

39

Child CPP

40 mm Hg

40

What is the minimal MAP required to sustain brain perfusion and life?

40 mm Hg

41

What should be done at the time of a brain injury?

Note use of ABCs

  • Response to painful stimuli only
  • GCS = 7 (less than 8 intubate)
  • Airway- intubated/end tidal CO2 monitor used
  • Ventilated 100% O2
  • Crystalloid fluid bolus to increase MAP
  • Unequal pupils - rapid transfer to hospital
  • VS = cushing's triad = represents decompensation
    • Increasing systolic BP (widening pulse pressure)
    • Bradycardia (full bounding pulse)
    • Irregular respiratory pattern

42

What does high CO2 cause?

cerebral vasodilation

43

What does low CO2 cause?

vasoconstriction

44

What should glucose be kept between?

80-110

45

What are ICP monitoring devices?

  • ICP monitoring is used to guide clinical care for a patient at risk for increased ICP
  • Gold standard it he ventriculostomy (catheter inserted into the lateral ventricle) which allows for monitoring of the pressure within the ventricle, facilitates removal/sampling of CSF, and allows for intraventricular drug administration
  • Infection is a potential complication. Strict aseptic technique is used during dressing changes or sampling of CSF
  • Monitoring devices may also be placed in the subarachnoid space, epidural space, or intraparenchymal space

46

What are goals in caring for a patient with increased ICP?

  1. Adequate oxygenation - endotracheal tube with mechanical ventilation may be necessary, maintain PaO2 greater than 100 mm Hg and PaCO2 30-40 mm Hg (PaCO2 is a potent vasodilator and increases will increase cerebral blood flow and thus ICP
  2. Maintaining adequate cerebral blood flow and tissue perfusion with SBP 100-160 mm Hg and CPP greater than 60 mm Hg
  3. Maintain adequate nutrition and hydration as the patient is in a hypermetabolic and hypercatabolic state which increases the need for glucose to meet the metabolic needs of the cerebral tissue
  4. No complications secondary to immobility and decreased LOC

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