A cuff that is too narrow will provide what type of reading for the patient's BP?

Appeared in: DSSSB -28 August 2019 (Shift-2)

Explanation

A blood pressure cuff that is too narrow for the arm's circumference fails to distribute pressure evenly over the brachial artery.
To achieve arterial occlusion with a narrow cuff, it must be inflated to a much higher pressure than the patient's actual intra-arterial pressure.
This requirement for excessive external pressure results in an artificially and falsely elevated systolic and diastolic reading.
The correct cuff bladder width should be about 40% of the arm circumference, and the length should encircle 80-100% of the arm.

Option A: A narrow cuff causes a falsely high reading, not a low one. The reading is also an error ('false'), not a true reflection of the patient's BP.
Option C: A false low reading is the result of using a blood pressure cuff that is too wide or large for the patient's arm.
Option D: While the reading is high, it is not a 'true' measurement. It is a 'false' high caused by a measurement artifact from using the wrong equipment.

Clinical Relevance

Nursing practice connection: Knowing Blood Pressure Measurement Accuracy helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Accurate blood pressure measurement is fundamental for diagnosing and managing hypertension. Using the wrong cuff size is a common error that can lead to significant clinical consequences.
A falsely high reading may lead to an incorrect diagnosis of hypertension, resulting in unnecessary prescription of antihypertensive medications, which can cause side effects like dizziness, hypotension, and falls.
Conversely, a falsely low reading (from a cuff that's too wide) can mask true hypertension, delaying necessary treatment and increasing the risk of cardiovascular events like stroke and heart attack.

How to Approach the Question

Identify the core concept of the question, which is the effect of incorrect blood pressure cuff size on the reading.
Focus on the specific error mentioned: 'a cuff that is too narrow'.
Recall the principle of BP cuff errors. A helpful mnemonic is: 'Too small (narrow) gives a reading that is too high; too large (wide) gives a reading that is too low.'
Apply this principle: A narrow cuff will produce a high reading.
Evaluate the options. Eliminate 'low reading' options (A and C).
Differentiate between the remaining 'high reading' options. Since the error is caused by equipment, the reading is not a true reflection of the patient's BP. Therefore, it is a 'false' high reading.

Concept Tested & Keywords

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E6 Nursing Fundamentals Taylor p. 131-133

E6 Nursing Fundamentals Potter Perry 12e Part 3 p. 28-30

Practise the full DSSSB -28 August 2019 (Shift-2)

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