|
Correct Answer: "sounds disappear."
blood pressure measurement involves the identification of specific sounds, known as korotkoff sounds, which correspond to various phases of blood flow through the arteries as the pressure from a blood pressure cuff changes. these sounds are crucial for determining systolic and diastolic blood pressures, and they are typically listened for using a stethoscope placed over the brachial artery at the elbow.
the first phase begins when the cuff's pressure is high enough to stop blood flow in the artery. as the cuff pressure is slowly released, blood begins to flow again, and the first sounds that can be heard through the stethoscope are the korotkoff sounds. phase 1 is characterized by faint tapping sounds that gradually increase in intensity. this initial appearance of sound corresponds to the systolic blood pressure.
in phase 2, the sounds develop a murmuring or squeaking quality as the blood flow through the artery becomes smoother despite the decreasing pressure in the cuff.
phase 3 is marked by crisper, louder sounds as blood flow increases and becomes more turbulent due to the further lowering of the cuff pressure.
by phase 4, the sounds become muffled and softer. this change in quality indicates that the artery is no longer being compressed enough to create significant turbulence as the cuff pressure continues to decrease.
finally, phase 5, which is the answer to the question, is characterized by the complete disappearance of sound. this occurs when the cuff pressure is low enough that it no longer restricts the blood flow, allowing the blood to flow freely and silently. the pressure level at which this silence occurs marks the diastolic blood pressure. thus, the disappearance of sound is a critical indicator used to determine the lower limit of blood pressure during a measurement.
|
