Which phase of the Koratkoff sound is defined as the diastolic pressure?

AIIMS Raipur - 2017 (shift-2)

Nursing Foundation

Easy

Appeared in: AIIMS Raipur - 2017 (shift-2)

Explanation

The diastolic blood pressure in adults is identified during Phase V of the Korotkoff sounds.
Phase V is marked by the complete disappearance of sound after the last regular tapping sound is heard.
This silence indicates that blood flow through the artery is no longer turbulent and has returned to a laminar (smooth) state, representing the pressure in the arteries when the heart is at rest between beats.

Option A: This describes Phase I, which corresponds to the systolic blood pressure, not the diastolic.
Option B: This describes Phase II, characterized by swishing sounds. It is an intermediate phase and does not define either systolic or diastolic pressure.
Option C: This describes Phase IV (muffling). While used as the diastolic pressure in specific populations (e.g., children, pregnant women), Phase V is the standard for adults.

Visual 1: Infographic: A chart illustrating the five phases of Korotkoff sounds against the decreasing pressure in the sphygmomanometer cuff. The chart should clearly label the systolic pressure at the onset of Phase I and the diastolic pressure at the onset of Phase V.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Korotkoff Sounds and Blood Pressure Measurement as background academic context rather than a clinical decision trigger.
Accurate identification of Korotkoff phases is a fundamental nursing skill for manual blood pressure measurement, which is essential for diagnosing and managing hypertension.
In some patients, sounds may persist all the way to 0 mmHg (e.g., in aortic regurgitation or high-output states). In these cases, the nurse should record Phase IV (muffling) as the diastolic pressure and document this finding.
What if? If a nurse is measuring the blood pressure of a 10-year-old child, they should use Phase IV (muffling of sounds) as the diastolic pressure, as this is the recommended standard for children.

How to Approach the Question

First, identify the core concept being tested: The question asks to link a specific Korotkoff sound phase to the definition of diastolic pressure.
Recall the five phases of Korotkoff sounds and their associated acoustic characteristics.
Remember that Phase I (the first sound heard) corresponds to the systolic pressure.
Remember that Phase V (the disappearance of all sounds) corresponds to the diastolic pressure in most adults.
Evaluate each option against this knowledge. Option A describes Phase I (systolic). Option B describes Phase II. Option C describes Phase IV (muffling). Option D correctly describes Phase V.
Select the option that describes the standard definition of diastolic pressure for the general adult population.

Concept Tested & Keywords

QPnavWKafRO8cMphrlg2w8