Systemic Vascular Resistance
- 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.
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
Will be incorrect if the CO measurement is inaccurate.
Should be understood as a semi-quantitative estimation; vasodilated, normal or vasoconstricted.