Calculate Pvr In Woods Units

PVR Equation:

\[ PVR = 80 \times (mPAP - PAWP) / CI \]

PVR (Woods Units):

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1. What is PVR Calculation?

Pulmonary Vascular Resistance (PVR) is a calculation used to quantify the resistance to blood flow from the pulmonary artery to the left atrium. It's an important hemodynamic measurement in assessing pulmonary hypertension and other cardiopulmonary conditions.

2. How Does the Calculator Work?

The calculator uses the PVR equation:

\[ PVR = 80 \times (mPAP - PAWP) / CI \]

Where:

\( mPAP \) — Mean Pulmonary Artery Pressure (mmHg)
\( PAWP \) — Pulmonary Artery Wedge Pressure (mmHg)
\( CI \) — Cardiac Index (L/min/m²)
80 — Conversion factor to Woods Units

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

3. Importance of PVR Calculation

Details: PVR measurement is crucial for diagnosing pulmonary hypertension, determining its severity, guiding treatment decisions, and assessing response to vasodilator therapy.

4. Using the Calculator

Tips: Enter mPAP and PAWP in mmHg, CI in L/min/m². All values must be valid (mPAP > 0, PAWP ≥ 0, CI > 0). The result is expressed in Woods Units.

5. Frequently Asked Questions (FAQ)

Q1: What are normal PVR values?
A: Normal PVR is typically less than 3 Woods Units (240 dyn·s·cm⁻⁵). Values above this may indicate pulmonary vascular disease.

Q2: How does PVR differ 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 indicated?
A: PVR is typically measured during right heart catheterization in patients with suspected pulmonary hypertension, heart failure, or before heart/lung transplantation.

Q4: What factors can affect PVR?
A: PVR can be affected by hypoxia, acid-base status, medications (vasodilators/vasoconstrictors), lung volume, and various disease states.

Q5: How is PVR used in clinical decision making?
A: PVR helps determine eligibility for certain treatments, assess operability in congenital heart disease, and guide management of pulmonary hypertension.