What phase of Korotkoff sounds indicates the diastolic pressure?

The phase of Korotkoff sounds that indicates diastolic pressure is Phase 5. This phase is characterized by a distinct change in the sound, typically described as a muffling or a disappearance of the Korotkoff sounds. As blood flow ceases through the brachial artery, the sound of the blood pulse is no longer heard, indicating that the pressure in the artery has dropped to the lowest level—the diastolic pressure.

During the measurement of blood pressure using a sphygmomanometer, the healthcare provider listens for these sounds to determine both systolic and diastolic readings. Phase 1 corresponds to the first clear sound heard, which marks systolic pressure. Phases 2 and 3 involve intermediate sounds, but it is Phase 5 that confirms the cessation of sound, effectively marking the end of the blood flow and establishing the diastolic pressure. Recognizing this phase is crucial for accurate blood pressure assessment.