1. What is Pulmonary Vascular Resistance (PVR)?

Pulmonary Vascular Resistance (PVR) is a measure of the resistance to blood flow in the pulmonary circulation. It is calculated as the pressure drop across the pulmonary vascular bed divided by the flow rate, typically expressed in Wood units.

2. How Does the Calculator Work?

The calculator uses the PVR equation:

Where:

• \( \Delta P \) — Pressure gradient across pulmonary vasculature (mmHg)
• \( Flow \) — Cardiac output (L/min)

Explanation: The equation calculates the resistance in the pulmonary circulation by dividing the pressure difference by the flow rate.

3. Importance of PVR Calculation

Details: PVR measurement is crucial for assessing pulmonary hypertension, evaluating right ventricular function, and guiding treatment decisions in cardiopulmonary diseases.

4. Using the Calculator

Tips: Enter the pressure gradient in mmHg and cardiac output in L/min. Both values must be greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What are normal PVR values?
A: Normal PVR is typically between 0.25-1.6 Wood units. Values above 3 Wood units indicate pulmonary hypertension.

Q2: How is PVR different from SVR?
A: PVR measures resistance in the pulmonary circulation, while SVR (Systemic Vascular Resistance) measures resistance in the systemic circulation.

Q3: When is PVR measurement important?
A: PVR is particularly important in evaluating patients with pulmonary hypertension, congenital heart disease, and before heart or lung transplantation.

Q4: How is ΔP measured in clinical practice?
A: ΔP is typically measured during right heart catheterization as the difference between mean pulmonary arterial pressure and pulmonary capillary wedge pressure.

Q5: Can PVR be converted to other units?
A: Yes, PVR can be converted to dyn·s·cm⁻⁵ by multiplying Wood units by 80.