Systemic Vascular Resistance

How-to

SVR is calculated from the Cardiac Output (CO) (or Cardiac Index (CI)) and the right atrial pressure (RAP) (or Central venous pressure (CVP).
Estimate CVP/RAP.
Small underfilled heart (5), normal (10) , enlarged IVC with full RA/RV (15).
Using 10 is acceptable in most cases, just trying to get an estimate of SVR.

Interpretation

SVR (dynes⋅sec⋅cm^-5) = 80 x [MAP-RAP] (mmHg) / CO (L/min)

SVRI = 80 x (MAP-RAP)/CI

Normal: 900-1200

Vasodialted: 400-900

Vasoconstricted: >1200

Tips

Will be incorrect if the CO measurement is inaccurate.

Should be understood as a semi-quantitative estimation; vasodilated, normal or vasoconstricted.

References

American Society of Echocardiography Guidlines: Assessment of Structure and Function