1. What is PVR?

PVR (Pulmonary Vascular Resistance) is a measure of the resistance to blood flow through the pulmonary circulation. It is calculated as the difference between mean pulmonary arterial pressure (mPAP) and pulmonary arterial wedge pressure (PAWP) divided by cardiac output (CO).

2. How Does the Calculator Work?

The calculator uses the PVR equation:

Where:

• \( mPAP \) — Mean Pulmonary Arterial Pressure (mmHg)
• \( PAWP \) — Pulmonary Arterial Wedge Pressure (mmHg)
• \( CO \) — Cardiac Output (L/min)

Explanation: The equation calculates the resistance in the pulmonary vasculature by measuring the pressure gradient across the pulmonary circulation divided by the flow rate.

3. Importance of PVR Calculation

Details: PVR is an important hemodynamic parameter used in the diagnosis and management of pulmonary hypertension. It helps assess the severity of pulmonary vascular disease and guide treatment decisions.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What are normal PVR values?
A: Normal PVR is typically less than 2 WU (Wood Units). Values above 3 WU are considered elevated and may 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 should PVR be measured?
A: PVR is typically measured during right heart catheterization in patients with suspected or known pulmonary hypertension.

Q4: What factors can affect PVR?
A: PVR can be affected by various factors including hypoxia, acid-base status, medications, and underlying lung or heart diseases.

Q5: How is PVR used in clinical practice?
A: PVR is used to diagnose pulmonary hypertension, assess disease severity, monitor response to treatment, and determine prognosis.