The phenomenon mainly occurs in the lower body, especially the lower extremities where pressure waves reflect back due to vessel branching, and the vessels are less compliant (stiffer) When a reflected wave is in phase with a forward wave, it generates a wave with higher amplitude. This concept requires an understanding of the effect of pressure wave reflection on the amplification of aortic pressure and thus pulse pressure. Compliance progressively decreases until it reaches a minimum in the femoral and saphenous arteries, and then it begins to increase again. Arterial compliance is approximately 2 mL/mm Hg, which confirms that normal pulse pressure is approximately 40 mm Hg.Īrterial compliance is equal to the change in volume (Delta V) over a given change in pressure (Delta P):īecause the aorta is the most compliant portion of the human arterial system, the pulse pressure is the lowest. Normal pulse pressure is, therefore, approximately 40 mmHg.Ī change in pulse pressure (delta Pp) is proportional to volume change (delta-V) but inversely proportional to arterial compliance (C):īecause the change in volume is due to the stroke volume of blood ejected from the left ventricle (SV), we can approximate pulse pressure as:Ī normal young adult at rest has a stroke volume of approximately 80 mL. The diastolic blood pressure is the minimum pressure experienced in the aorta when the heart is relaxing before ejecting blood into the aorta from the left ventricle (approximately 80 mmHg). The systolic blood pressure is defined as the maximum pressure experienced in the aorta when the heart contracts and ejects blood into the aorta from the left ventricle (approximately 120 mmHg). ![]() Pulse Pressure = Systolic Blood Pressure – Diastolic Blood Pressure.Pulse pressure is the difference between systolic and diastolic blood pressures.
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