Pvr Wood Unit Calculator

PVR Equation:

\[ PVR = \frac{mPAP - PCWP}{CO} \]

Estimated PVR (Wood Units):

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1. What is the PVR Wood Unit Equation?

The PVR (Pulmonary Vascular Resistance) Wood Unit equation calculates the resistance in the pulmonary circulation. It is an important hemodynamic parameter used in the assessment of pulmonary hypertension and other cardiopulmonary conditions.

2. How Does the Calculator Work?

The calculator uses the PVR equation:

\[ PVR = \frac{mPAP - PCWP}{CO} \]

Where:

\( mPAP \) — Mean Pulmonary Artery Pressure (mmHg)
\( PCWP \) — Pulmonary Capillary Wedge Pressure (mmHg)
\( CO \) — Cardiac Output (L/min)

Explanation: The equation calculates the resistance to blood flow through the pulmonary vasculature by measuring the pressure gradient across the pulmonary circulation divided by the cardiac output.

3. Importance of PVR Calculation

Details: PVR measurement is crucial for diagnosing pulmonary hypertension, determining disease severity, guiding treatment decisions, and monitoring response to therapy in patients with cardiopulmonary disorders.

4. Using the Calculator

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

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 are considered elevated and may indicate pulmonary hypertension.

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 measurement is indicated in the evaluation of pulmonary hypertension, heart failure, congenital heart disease, and before heart or lung transplantation.

Q4: What factors can affect PVR values?
A: PVR can be affected by hypoxia, acid-base status, vasoactive medications, lung volume, and various disease states affecting the pulmonary vasculature.

Q5: How is PVR measured clinically?
A: PVR is typically measured during right heart catheterization by obtaining pressure measurements and calculating cardiac output using thermodilution or Fick method.