Intracranial Pressure (ICP) Fundamentals (6)

• The quiz includes 25 multiple-choice questions and 10 select-all-that-apply questions.
• Answers and rationales are provided for each question.

Normal Intracranial Pressure (ICP)

• Normal ICP in adults ranges from 5-15 mmHg.
• Sustained pressures greater than 20 mmHg may require intervention.
• Pressures greater than 40 mmHg are life-threatening.

Monro-Kellie Hypothesis

• States that the total volume of brain tissue, CSF, and blood must remain constant to maintain normal ICP.

Cerebral Perfusion Pressure (CPP)

• CPP is calculated using the formula: CPP = MAP - ICP.
• This helps determine the pressure available to perfuse brain tissue.
• CPP < 50 mmHg suggests a risk of irreversible brain ischemia and poor neurologic outcomes.

Cerebrospinal Fluid (CSF) Function

• CSF cushions, nourishes, and removes waste from CNS tissues.

CPP Calculation Example

• A patient with a MAP of 90 mmHg and an ICP of 25 mmHg has a CPP of 65 mmHg (90-25=65).
• A CPP value close to 60 is borderline and sustained lower values can harm the brain.

Cushing's Triad

• Includes hypertension, bradycardia, and irregular respirations.
• Indicates increased ICP and brainstem compression.

Posturing

• Decorticate posturing (flexion of arms, clenched fists, and extended legs) is associated with lesions above the brainstem.

Interventions for Elevated ICP

• Keeping the head midline and elevated helps promote venous drainage, reducing ICP.

Glasgow Coma Scale (GCS)

• Used to assess the level of consciousness (LOC) in patients with neurological injuries.

Ventriculostomy Management

• The external ventricular drain (EVD) must be leveled with the foramen of Monro (approx. at the tragus) to ensure accurate CSF drainage.

Medications for Increased ICP

• Mannitol is an osmotic diuretic used to reduce cerebral edema and decrease ICP.

Concerning Findings with Elevated ICP

• For a patient with an ICP of 30 mmHg, irregular respirations are the most concerning finding.
• Irregular respirations are part of Cushing's triad, suggesting brainstem herniation, a medical emergency.

Indicator of Neurological Function

• Level of consciousness is the earliest and most sensitive indicator of neurological deterioration.

Lumbar Puncture and ICP

• Lumbar puncture is contraindicated in patients with increased ICP, as it may cause brain herniation.

Impact of MAP and ICP on CPP

• If a patient has a MAP of 100 mmHg and an ICP of 30 mmHg, the nurse should anticipate decreased CPP.
• CPP = 70 mmHg which is within normal range.
• If ICP rises further, CPP will drop dangerously.

Mannitol Effectiveness

• Increased urine output and neurological improvement are indicators that mannitol is effective.

Risk Factors for Increased ICP

• Brain tumors are space-occupying lesions that can raise ICP.

Nursing Intervention for Decerebrate Posturing

• Decerebrate posturing indicates brainstem damage, requiring immediate action.

GCS Score Priority

• When caring for a patient with a GCS score of 6, preparing for intubation is the priority.
• A GCS < 8 indicates coma and risk of airway compromise.

Early Signs of Increased ICP

• Early signs include headache, nausea and vomiting, and changes in level of consciousness (LOC).
• Bradycardia and fixed pupils are late signs

Conditions Leading to Increased ICP

• Conditions include brain tumor, hydrocephalus, and encephalitis.
• All are neurological conditions that affect intracranial volume.

Interventions to Reduce ICP

• Interventions that help reduce ICP are elevating HOB to 30 degrees, administering mannitol, and keeping the head midline.
• These improve venous return and decrease ICP.
• Suctioning and Trendelenburg increase ICP.

Focused Neurological Exam Assessments

• Assessments are Glasgow Coma Scale, Pupillary response, Motor strength and Sensory perception.
• These assess brain and spinal cord function.

Components of Cushing's Triad

• Components are hypertension, bradycardia, and irregular respirations.
• These are classic late signs of increased ICP indicating brainstem involvement.

Findings Indicating Worsening Intracranial Pressure After Head Injury

• Findings are unilateral dilated pupil, GCS score drop, and vomiting without nausea.
• Sudden changes in GCS and projectile vomiting are warning signs.

VP Shunt Teaching

• Teaching should include reporting signs of infection, avoiding contact sports, and monitoring for abdominal distension.
• Contact sports can damage the shunt.

Nursing Diagnoses for Increased ICP

• Diagnoses are Decreased Intracranial Adaptive Capacity, Risk for Ineffective Cerebral Tissue Perfusion, and Impaired Mobility.
• Relate to the neurological status and motor response affected by increased ICP.

Meningitis Symptoms

• Symptoms include fever, nuchal rigidity, and photophobia.

Preventing Further Increases in ICP

• The nurse should provide stool softeners, space care, and keep the neck neutral.
• Minimizing straining, reduce stimulation and positioning properly prevent spikes in ICP.

Priority Action for Hydrocephalus Patient

• A patient with a history of hydrocephalus presenting with lethargy and vomiting should be evaluated because this may indicate VP shunt malfunction and increased ICP.

Responding to Sustained ICP

• For a patient's ICP monitor showing a sustained pressure of 28 mmHg, immediate provider notification is required for intervention.
• Sustained ICP > 20 mmHg is dangerous.

Brain Damage and Decerebrate Posturing

• Decerebrate posture indicates a lesion in the brainstem, which controls reflexes and autonomic function.

GCS Score of 8 Significance

• A GCS of 8 or below indicates coma and impaired airway protection, so intubation is often necessary.

Cause of Fixed, Dilated Pupils

• For a patient with suspected brain herniation presenting with fixed, dilated pupils occur due to cranial nerve III (oculomotor) compression, often from herniation due to extreme ICP.