How many phases of Korotkoff sounds are typically heard when measuring blood pressure?

When measuring blood pressure, five distinct phases of Korotkoff sounds are typically identified. The first phase, known as Phase I, is characterized by the clear tapping sound that corresponds to the systolic pressure, indicating the onset of blood flow as the cuff pressure is released. Subsequent phases include the softer sounds in Phase II, which occur as blood flow continues to increase and the pressure in the cuff declines. Phase III is marked by a return of sharper, more distinct sounds, while Phase IV features a muffling of sounds as blood flow becomes more laminar. Finally, in Phase V, the sounds completely disappear, indicating the diastolic pressure. Each phase provides valuable information regarding the status of arterial blood flow and the pressure within the arteries.

The identification of these five phases is crucial for accurately determining both systolic and diastolic pressures. This structured method of listening to the different sounds helps ensure that healthcare professionals can reliably assess a patient’s blood pressure.