1. What is PVR?

PVR (Pulmonary Vascular Resistance) is a calculation used to measure the resistance to blood flow from the pulmonary artery to the pulmonary vein. It's an important hemodynamic parameter in assessing pulmonary hypertension and right heart function.

2. How Does the Calculator Work?

The calculator uses the PVR formula:

Where:

• \( \Delta P \) — Pressure gradient (mmHg)
• \( Q \) — Flow rate (L/min)

Explanation: The equation calculates the resistance in the pulmonary vasculature by dividing the pressure difference by the cardiac output.

3. Importance of PVR Calculation

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

4. Using the Calculator

Tips: Enter pressure gradient in mmHg and flow rate in L/min. Both values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a normal PVR value?
A: Normal PVR is typically between 0.25-1.6 mmHg·min/L (or 20-130 dyn·s·cm⁻⁵ when converted).

Q2: When is PVR measurement indicated?
A: PVR is measured in patients with suspected pulmonary hypertension, congenital heart disease, or when evaluating candidates for heart or lung transplantation.

Q3: 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.

Q4: What factors can affect PVR?
A: PVR can be affected by hypoxia, acidosis, various medications, lung diseases, and cardiac conditions.

Q5: How is PVR measured clinically?
A: Clinically, PVR is typically measured during right heart catheterization using pressure measurements and cardiac output determination.