1. What is Systemic Vascular Resistance?

Systemic Vascular Resistance (SVR) represents the resistance to blood flow offered by all of the systemic vasculature, excluding the pulmonary circulation. It's an important hemodynamic parameter that helps assess cardiovascular function.

2. How Does the Calculator Work?

The calculator uses the SVR equation:

Where:

• \( MAP \) — Mean arterial pressure (mmHg)
• \( CVP \) — Central venous pressure (mmHg)
• \( CO \) — Cardiac output (L/min)
• 80 — Conversion factor to dyn·s·cm⁻⁵

Explanation: The equation calculates the resistance to blood flow in the systemic circulation by accounting for the pressure gradient and cardiac output.

3. Importance of SVR Calculation

Details: SVR is crucial for assessing hemodynamic status, guiding vasopressor therapy, and evaluating conditions like septic shock, heart failure, and hypertension.

4. Using the Calculator

Tips: Enter MAP and CVP in mmHg, CO in L/min. All values must be valid (MAP > CVP, CO > 0).

5. Frequently Asked Questions (FAQ)

Q1: What are normal SVR values?
A: Normal range is 800-1200 dyn·s·cm⁻⁵. Values below 800 indicate low resistance (vasodilation), above 1200 indicate high resistance (vasoconstriction).

Q2: How is MAP calculated?
A: MAP ≈ (2 × diastolic BP + systolic BP) / 3, or can be measured directly via arterial line.

Q3: When is SVR measurement most useful?
A: In critical care settings for patients with shock (septic, cardiogenic, hypovolemic) or during complex hemodynamic management.

Q4: Are there limitations to this calculation?
A: Accuracy depends on precise measurement of MAP, CVP, and CO. Assumes steady-state conditions.

Q5: How does SVR differ from PVR?
A: PVR (pulmonary vascular resistance) measures resistance in pulmonary circulation, while SVR measures systemic circulation resistance.