Overview
One Wood unit equals 80 dyn·s/cm⁵. The summary displays resistance in both units, while the baseline PVR slider uses WU and the SVR slider uses dyn·s/cm⁵.
The program derives resistance from a pressure gradient divided by the appropriate flow. SVR uses systemic arterial minus RA mean pressure with systemic flow; PVR uses PA minus wedge mean pressure with pulmonary flow.
Resistance is undefined at zero flow. A shunt or bypass changes which flow belongs in the calculation. The optional Quiz calculations are not required to answer its interpretation questions.