ICP-CVA

Increased Intracranial Pressure

Definition

  • Increased intracranial pressure (ICP) is a condition where the pressure inside the skull increases, which can be harmful to brain tissues.

Causes of Increased ICP

  • Cerebrovascular Accident (CVA)

  • Head injury/Trauma

    • Concussion: Violent jarring of the brain.

    • Contusion: Bruise effect on brain tissue.

  • Infections

    • Encephalitis: Affects the inner layer of the meninges.

    • Meningitis: Affects the outer layer of the meninges.

  • Cerebral Edema: Swelling of the brain due to injury or disease.

  • Neoplasm: Tumors located in or around the brain.

  • Cerebral Hemorrhage/Aneurysm rupture: Bleeding within or around the brain.

  • Cerebral/Subdural Hematoma: Accumulation of blood in the brain.

  • Hydrocephalus: Excess cerebrospinal fluid (CSF) in the ventricles.

  • Status Epilepticus: Prolonged seizure activity.

Normal ICP Levels

  • Normal ICP is typically between 0-15 mmHg.

    • Increased ICP may be noted in levels above 20 mmHg, with Brunner indicating a threshold may begin at 5 mmHg.

Temporal Lobe Compression

  • Compression on nerve structures, which could result in various neurological deficits.

Monro-Kellie Doctrine

  • Describes the relationship between brain volume, blood volume, and CSF volume.

    • Formula: ICP = V1 + V2 + V3 + V4

      • Where:

        • V1 = Brain volume

        • V2 = Blood volume

        • V3 = CSF volume

        • V4 = Mass, lesion, etc.

Monitoring ICP

  • Traumatic Closed Head Injuries: Intracranial pressure monitors may be used to assess blood and brain volume changes post-injury.

Cerebral Perfusion Pressure (CPP)

  • CPP is the pressure needed to ensure blood flow to the brain.

    • Calculated as: CPP = MAP - ICP

    • Normal CPP is between 70-100 mmHg.

Example Calculation

  • Example BP of 120/80 gives a MAP of 93.33 mmHg. If ICP is 15 mmHg, then:

    • CPP = 93 - 15 = 78 mmHg (normal is 70-100 mmHg).

    • A rising ICP leads to decreasing CPP, indicating ineffective cerebral perfusion.

Clinical Presentation of Increased ICP

  • Changes in Level of Consciousness (LOC): confusion, lethargy, coma.

  • Headache: often persistent and severe.

  • Flattening of Affect: emotional dullness.

  • Seizures: potential for increased ICP to induce seizure activity.

  • Impaired Sensory & Motor Function: weakness, altered sensation.

  • Eyes: Papilledema and pupillary changes.

  • Vital Signs: May show Cushing's triad: hypertension, bradycardia, irregular respirations.

  • Posturing: Decerebrate (extensor) or decorticate (flexor) postures may indicate severe brain injury.

    • Vomiting: could be projectile and may not be preceded by nausea.

    • Infants: may show bulging fontanels, cranial suture separation, and high-pitched cries.

Assessment Scales

  • Glasgow Coma Scale (GCS): Assesses consciousness based on verbal, motor, and eye-opening responses.

    • Maximum Score: 15; lowest is 3.

  • Pupil Reactivity Score: Evaluates pupil response to light as an indicator of brain function.

Levels of Consciousness (LOC)

  • Level I: Alert and oriented.

  • Level II: Lethargy/somnolence; responds to verbal stimuli.

  • Level III: Obtunded; requires strong stimuli for response.

  • Level IV: Stuporous; minimal responses, potential vomiting.

  • Level V: Coma; no spontaneous movements and response to stimuli is poor.

Posturing as a Reflex to ICP

  • Decerebrate Posture: Indicating severe brain injury; all extremities in rigid extension.

  • Decorticate Posture: Indicative of damage to the cerebral cortex; arms flexed and legs extended.

Cushing's Triad

  • Increased Systolic BP with a widening pulse pressure, accompanied by bradycardia and irregular respiration patterns.

Cerebral Herniation Types

  • Subfalcine: Herniation of the cingulate gyrus.

  • Transtentorial: Includes uncal herniation that may compress the brainstem.

  • Tonsillar: Cerebellar tonsils compressing the medulla and brainstem.

Nursing Management of Increased ICP

  • Regularly monitor vital signs, MAP, ICP, GCS, cranial nerves.

  • Position patient at 30 to 45 degrees to promote venous drainage.

  • Osmotic diuretics like Mannitol can decrease cerebral edema.

  • Employ steroids to manage inflammation.

  • Reduce metabolic demand on the brain; manage temperature and ventilation.

  • Prevent Valsalva Maneuver to avoid sudden increases in intracranial pressure.

HOB CARE

HEAD @ 30 DEGREES

OXYGENATATION MONITORING

BODY TEMP

CLOSE MONITOR OF SEIZURE

AVOID STRAINING

REDUCE NOISE AND LIGHT

EXAMINE FOR SIGNS OF HERNIATION