4.2 Cardiovascular: Pressure, Flow and Resistance

[@KeenestObserver]

When the scientific litterature gives the mean pressure values of pressure waveforms, are they presenting a **difference** in pressure compared to an arbitrary point ( such as right atrial pressure) or is it the **actual** pressure? This is extremely important because in the Windkessel model, we model the blood circulation like an electric circuit where the change in pressure is analogous to the change in electric potential (the electric voltage). It is really not clear when people are reffering to pressure or to a change in pressure... (which is obviously needed for our model) Hence if the pressure at the veins is 5mmHg, is that the actual pressure or is it a pressure difference between the veins and some arbitrary point? This allows me to know if I can use 5mmHg as the pressure difference between the veins and the aorta, OR if I would have to substract 5mmHg with the pressure at a point in the aorta to get the difference in pressure.

[@Hippomedics]

5mmHg is the actual pressure in the veins, relative to atmospheric pressure. All pressures stated are actual pressures unless explicitly stated otherwise.

[@AreeshaKaif]

Good