Calculate the cerebral perfusion pressure of a client whose mean arterial pressure is 72 mmHg and intracranial pressure is 24 mmHg.

Appeared in: PGIMER Chandigarh NO - 2015

Explanation

Cerebral perfusion pressure (CPP) is the pressure gradient that drives blood flow to the brain.
It is calculated by subtracting the intracranial pressure (ICP) from the mean arterial pressure (MAP).
Using the formula CPP = MAP - ICP, the calculation is 72 mmHg - 24 mmHg = 48 mmHg.
A normal CPP is 70 to 100 mmHg; a value of 48 mmHg indicates severe cerebral ischemia.

Option A: This value represents the upper limit of a normal CPP but is not the correct calculation for this patient.
Option C: This is the sum of MAP and ICP (72 + 24 = 96), which is an incorrect application of the formula.
Option D: This is a mathematical miscalculation of the provided values.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculation of Cerebral Perfusion Pressure (CPP) as background academic context rather than a clinical decision trigger.
Maintaining a CPP between 70 and 100 mmHg is essential to ensure adequate cerebral blood flow and prevent brain tissue ischemia.
A CPP below 50 mmHg is a grave clinical sign that can lead to irreversible neurologic damage and brain death.
What if? If the patient's CPP drops to 48 mmHg, the nurse should immediately anticipate interventions to increase MAP (e.g., vasopressors) or decrease ICP (e.g., mannitol, hyperventilation) to restore perfusion.

How to Approach the Question

Identify the goal of the question: Calculate the cerebral perfusion pressure (CPP).
Recall the standard formula: CPP = MAP - ICP.
Extract the given values from the clinical scenario: MAP = 72 mmHg and ICP = 24 mmHg.
Perform the subtraction: 72 - 24 = 48.
Select the option that matches the calculated result.

Concept Tested & Keywords

Concept Tested: Calculation of Cerebral Perfusion Pressure (CPP)
Stem keywords: cerebral perfusion pressure, mean arterial pressure, 72 mmHg, intracranial pressure, 24 mmHg
Lead-in keywords: Calculate
Clinical cues: MAP of 72 mmHg and ICP of 24 mmHg indicate a critically low CPP of 48 mmHg, requiring immediate intervention.

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Practise the full PGIMER Chandigarh NO - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.