Systemic Vascular Resistance

How to use it

1. 1

   Obtain invasive measurements. MAP from arterial line, CVP from CVC, CO from thermodilution or echo.

2. 2

   Calculate. SVR = (MAP − CVP) ÷ CO × 80. Units convert to dynes·s·cm⁻⁵.

3. 3

   Classify shock type. Low SVR + high CO → distributive. High SVR + low CO → cardiogenic.

When to use it

Differentiating shock type

Guides whether to give vasopressors (low SVR) or inotropes (high SVR + low CO).

PA catheter haemodynamics

Complete haemodynamic profile: CO, CI, SVR, PCWP, PVR guides optimisation of patients in cardiogenic shock.

Vasodilator titration

SVR monitoring during nitroprusside or nitroglycerine infusion to prevent excessive hypotension.