Increased Intracranial Pressure (ICP) - Lecture Notes

Introduction

• Instructor: Cereth, Registered Nurse
• Topic: Increased Intracranial Pressure (ICP)
• Context: Part of NCLEX review series on the neuro system
• Importance: This is a medical emergency; requires fast treatment to prevent brain death

Understanding Intracranial Pressure

• Definition: Pressure within the skull that has dramatically increased
• Normal ICP: 5-15 mmHg
• Emergency ICP Level: Greater than 20 mmHg
• Components Contributing to ICP:
  • Cerebral spinal fluid (CSF)
  • Brain tissue
  • Blood
• Measurement: Special devices in the lateral ventricle or subarachnoid space

Factors Influencing ICP

• Body Temperature: Hyperthermia increases ICP
• Oxygenation: Hypoxia and high CO2 levels cause vasodilation and increase ICP
• Body Position: Neck alignment and bed angle (30-35 degrees) affect ICP
• Pressure Levels: Arterial/venous pressure, intra-abdominal/thoracic pressure

Monroe-Kellie Hypothesis

• Concept: The volume of brain, CSF, and blood must remain constant
• Compensatory Mechanisms:
  • Displacement of CSF
  • Vasoconstriction of cerebral arteries
• Limitations: Body compensation is limited, may lead to Cushing's triad

Cerebral Perfusion Pressure (CPP)

• Definition: Pressure needed to push blood to the brain
• Normal Range: 60-100 mmHg
• Formula: CPP = MAP - ICP
  • Example Calculation: CPP = 58 (MAP) - 19 (ICP) = 39 (not adequate)

Conditions Leading to Increased ICP

• Head trauma
• Increased cerebral spinal fluid
• Hemorrhage or hematoma
• Hydrocephalus
• Brain tumors
• Infections (encephalitis, meningitis)

Pathophysiology of Increased ICP

• Consequences of High ICP:
  • Ischemia and decreased blood flow to brain tissue
  • Activation of Monroe-Kellie hypothesis
  • Potential for brain herniation and death
• Early Signs: Mental status changes
• Late Signs: Cushing's triad (increased systolic BP, decreased heart rate, irregular respirations)

Signs and Symptoms

• Mnemonic: MIND CRUSH
  • M: Mental status changes
  • I: Irregular breathing (Cheyne-Stokes)
  • N: Nerve changes (optic nerve swelling, papilledema)
  • D: Decerebrate or decorticate posturing
  • C: Cushing's triad
  • R: Reflexes (positive Babinski)
  • U: Unconsciousness
  • S: Seizures
  • H: Headache and projectile vomiting

Nursing Interventions

• Goals: Prevent further increase in ICP, monitor ICP, and care for unconscious patients
• Mnemonic: PRESSURE
  • P: Positioning (head midline and 30-35 degrees)
  • R: Respiratory (prevent hypoxia/hypercapnia)
  • E: Elevated temperature (prevent hyperthermia)
  • S: Systems to monitor (neuro checks, Glasgow Coma Scale)
  • S: Straining activities (avoid)
  • U: Unconscious patient care
  • R: Prescriptions (barbiturates, vasopressors, antihypertensives, anticonvulsants)
  • E: Edema management (mannitol)

Medications and Management

• Barbiturates: Decrease brain metabolism
• Vasopressors/Antihypertensives: Regulate blood pressure
• Anticonvulsants: Prevent seizures
• Mannitol: Dehydrates brain, reduces swelling
• Corticosteroids: Manage protein leakage and reduce swelling

Conclusion

• Recap: Early detection and response are critical
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