What is the normal SVR range and how does it change in shock?

Normal SVR is 800–1200 dynes·sec/cm⁵. Distributive shock (septic, anaphylactic, neurogenic) features markedly reduced SVR ( 1800) with low cardiac output — the compensatory vasoconstriction pattern. Hypovolemic shock shows elevated SVR as the body compensates by vasoconstriction to maintain MAP. Obstructive shock (massive PE, tamponade) also shows elevated SVR.

How is SVR used to guide vasopressor and vasodilator therapy?

In distributive shock with low SVR, vasopressors (norepinephrine first-line) increase SVR to restore perfusion pressure. Target SVR of 800–1000 is a reasonable hemodynamic goal. In cardiogenic shock with very high SVR, vasodilators (nitroprusside, nitroglycerin) reduce afterload and improve forward cardiac output. SVR must be interpreted alongside cardiac output — normal SVR with low CO (and normal MAP) may indicate occult cardiogenic compromise requiring different management than true distributive shock.

Systemic Vascular Resistance (SVR)

Calculate systemic vascular resistance using SVR = (MAP − CVP) × 80 / CO to assess afterload, guide vasopressor/vasodilator therapy, and differentiate shock states.

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Systemic Vascular Resistance (SVR)

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Frequently Asked Questions

What is the normal SVR range and how does it change in shock?

How is SVR used to guide vasopressor and vasodilator therapy?