14.6 : コロトコフサウンド

Korotkoff sounds are a sequence of sounds corresponding to shifts in blood flow through an artery during gradual cuff deflation in a blood pressure assessment.

When the cuff is inflated beyond the systolic pressure, it completely blocks blood flow, resulting in the absence of Korotkoff sounds.

These sounds appear when the cuff pressure equals the systolic blood pressure and are audible in five distinct phases.

During phase one, a gentle and distinct tapping sound emerges, indicating the systolic pressure reading.

In phase two, the tapping sounds gradually diminish, accompanied by a gentle swishing sound.

During phase three, the tapping sounds become crisper and more intense but remain softer compared to phase one.

In phase four, softer, muffled sounds are heard as the cuff pressure is released. The first diastolic reading marks the change from tapping to a muffled sound.

Finally, in the fifth phase, all sounds disappear as the cuff deflates, indicating normal blood flow. This point is marked as the diastolic blood pressure.