Pulse Pressure

Pulse Pressure

Definition: Systolic BP - Diastolic BPExample: 120 - 80 = 40 mmHg

Variations in Pulse Pressure are due to:

• changes in compliance of aorta
• changes in stroke volume

Factors that determine pulse pressure

It is helpful to think of the definition of compliance C = ∆V/∆P and rearrange this to think about factors governing ∆P (stroke volume).

∆P = ∆V/C

Factors affecting systolic pressure

1. Compliance of the aorta
• A highly compliant aorta (i.e., less stiff) has a smaller pulse pressure for a given stroke volume into the aorta.
• A larger stroke volume (not shown in the figure) produces a larger pulse pressure at any given compliance.
• Aortic compliance decreases with age due to structural changes, thereby producing age-dependent increases in pulse pressure.
• For a given stroke volume, compliance determines pulse pressure and not mean aortic pressure.
• However, because vessels display dynamic compliance, increasing the rate of ventricular ejection (as occurs with increased ventricular inotropy) will increase the pulse pressure compared to the same volume ejected at a lower rate.

2. Stroke Volume

Factors affecting diastolic pressure

3. Rate of runoff

3.  Runoff time

References: http://www.cvphysiology.com/Blood%20Pressure/BP002.htm

John Wood, PhD,  KUMC, lecture Power Points