Which Korotkoff's sound is most closely associated with diastolic pressure?

Korotkoff sounds are the series of sounds that healthcare providers listen for when measuring blood pressure using a sphygmomanometer. These sounds occur in five distinct phases during the deflation of the cuff. The fifth phase, which is the correct answer, is particularly significant for identifying diastolic pressure.

In the context of blood pressure measurement, diastolic pressure is defined as the pressure in the arteries when the heart is at rest between beats. This level reflects the lowest pressure in the arteries, and it is represented by the point at which the Korotkoff sounds disappear completely. Specifically, during Phase V, the sounds cease as the blood flow becomes laminar again, indicating that the pressure inside the cuff has fallen below the diastolic pressure.

Understanding the relationship between these sounds and pressure measurements is crucial for accurate assessment. For instance, Phase IV (another significant point) tends to be associated with a muffling of sounds and can sometimes also be considered for diastolic readings in certain clinical situations, such as in children or in conditions affecting the aorta. However, the standard practice in adults is to use Phase V for diastolic pressure.

In summary, the fifth Korotkoff sound marks the transition to laminar