What Is the Systemic Vascular Resistance (SVR) Calculator?
SVR represents the afterload against which the left ventricle must pump to eject blood into the aorta.
How Does the Systemic Vascular Resistance (SVR) Calculator Work?
Calculates pressure gradient ΔP = MAP - CVP.
Divides by cardiac output and multiplies by 80 to obtain dynes·sec/cm⁵.
Systemic Vascular Resistance (SVR) Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
SVR = [ (MAP - CVP) / CO ] · 80 dyn·s/cm⁵, Wood Units = (MAP - CVP) / CO
Hydraulic Ohm law analog where 80 converts mmHg·min/L to CGS dyne·sec/cm⁵.
How to Use the Systemic Vascular Resistance (SVR) Calculator
- Input MAP, CVP, and measured cardiac output.
Step-by-Step Example Calculation
Post-operative Hemodynamics
Input Values:
map:90
cvp:6
cardiacOutput:5
Worked Steps: Normal resting values yielding SVR of ~1344 dyn·s/cm⁵.
Understanding Your Result
Normal SVR: 800 to 1,200 dyn·s/cm⁵.
< 800 indicates vasodilation (distributive/septic shock).
> 1,200 indicates severe vasoconstriction (cardiogenic shock or excessive vasopressors).
Factors That Affect the Result
- Vascular tone, sympathetic stimulation, and vasoactive infusions.
When Should You Use This Calculator?
- ICU hemodynamic optimization and titration of inotropes and vasopressors.
Assumptions & Limitations
- Assumes laminar steady flow.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard clinical hemodynamics formulation.