Which Korotkoff's sound is associated with a patient's systolic blood pressure?

The sound associated with a patient's systolic blood pressure is the first Korotkoff sound, which is identified as phase I. During the measurement of blood pressure using a sphygmomanometer, the healthcare provider inflates the cuff until the blood flow is occluded. As the cuff is slowly deflated, the first sound heard indicates the pressure at which blood first flows back into the artery, marking the systolic pressure. This sound is characterized by a clear, tapping noise.

Understanding this phase is crucial because it serves as a key reference point for assessing the upper limit of blood pressure. Subsequent phases (II, III, and IV) represent changes in blood flow dynamics as the cuff pressure continues to drop, but they do not correspond to systolic pressure. Thus, recognizing phase I as the first Korotkoff sound emphasizes its role in defining what constitutes the systolic reading in blood pressure assessments.