Systemic Vascular Resistance (SVR): A measure of the resistance that must be overcome to push blood through the circulatory system.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Evaluation of afterload in shock states.
Differentiating between types of shock (e.g., distributive shock with low SVR vs. cardiogenic shock with high SVR).
Titrating vasodilator or vasopressor therapy in the ICU/CCU.
Section 2
Formula & Logic
Formula
SVR = [(MAP − CVP) / CO] × 80
Where MAP = Mean Arterial Pressure, CVP = Central Venous Pressure, CO = Cardiac Output.
Normal Range
Normal SVR is typically 800–1200 dyn·s/cm⁵.
Section 3
Pearls/Pitfalls
Afterload Markers
SVR represents the resistance against which the left ventricle must pump. In cardiogenic shock, the body typically compensates by increasing SVR (vasoconstriction) to maintain blood pressure, which further strains the failing heart.
Section 4
Next Steps
Complementary Calculators
Fick Cardiac Output
PVR Calculator
Cardiac Output Index
MAP Calculator
Stroke Volume Index
Section 5
Evidence Appraisal
Physiological Standard
Recherches expérimentales sur le mouvement des liquides dans les tubes de très petits diamètres.
Poiseuille JLM. • Mémoires des Savants Étrangers.. 1844;Poiseuille's Law is the physical basis for calculating vascular resistance.
