PVR Calculator (Pulmonary Vascular Resistance)
HealthCalculate pulmonary vascular resistance in Wood units and dynes from mean PA pressure, wedge pressure, and cardiac output, with normal-range interpretation.
Mean PA Pressure
mmHg
Wedge Pressure (PCWP)
mmHg
Cardiac Output
L/min
Pulmonary Vascular Resistance
0Wood units
Normal: <2 WU
—
In dynes·s·cm⁻⁵0
Not a substitute for clinical evaluation. PVR should be interpreted alongside full right-heart catheterization data by a qualified healthcare provider.
What is a PVR?
The PVR Calculator computes pulmonary vascular resistance (PVR) from mean pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac output — three values typically obtained during right-heart catheterization. PVR is expressed in both Wood units and the traditional dynes.s.cm^-5 unit.
Enter your three hemodynamic values to see PVR in both units, along with an interpretation relative to the normal range. For related hemodynamic tools, see the Cardiac Index Calculator and Cardiac Output Calculator.
How to use this PVR calculator
- Enter the Mean Pulmonary Artery Pressure in mmHg, typically obtained from right-heart catheterization.
- Enter the Pulmonary Capillary Wedge Pressure in mmHg.
- Enter the Cardiac Output in liters per minute.
- Review the PVR result in Wood units and dynes.s.cm^-5.
- Compare the result against the normal-range interpretation shown, and discuss any elevated value with a qualified provider.
Formula & Methodology
PVR (Wood units) = (Mean PA Pressure − PCWP) ÷ Cardiac Output PVR (dynes·s·cm⁻⁵) = PVR (Wood units) × 80 Interpretation: PVR below 2 Wood units is normal, 2-3 Wood units is borderline elevated, and above 3 Wood units suggests a meaningful pulmonary vascular component, consistent with ESC/ERS pulmonary hypertension guideline thresholds. Worked example: A mean PA pressure of 35 mmHg, a wedge pressure of 10 mmHg, and a cardiac output of 5 L/min give PVR = (35 − 10) ÷ 5 = 5 Wood units, or 5 × 80 = 400 dynes·s·cm⁻⁵ — an elevated result suggesting a significant pulmonary vascular component.
Frequently Asked Questions
Pulmonary vascular resistance measures how much resistance the pulmonary circulation offers against blood flow from the right ventricle, calculated from the pressure drop across the pulmonary vascular bed divided by cardiac output. It is a key hemodynamic value in evaluating pulmonary hypertension and right-heart function.
PVR (Wood units) equals mean pulmonary artery pressure minus pulmonary capillary wedge pressure, divided by cardiac output. To convert Wood units to dynes.s.cm^-5, the more traditional unit, multiply by 80.
Pulmonary capillary wedge pressure (PCWP) approximates left atrial pressure, so subtracting it isolates the pressure drop attributable specifically to the pulmonary vasculature rather than pressure that's simply backing up from the left side of the heart. This distinction matters for separating pre-capillary from post-capillary causes of pulmonary hypertension.
A PVR below 2 Wood units (roughly under 160 dynes.s.cm^-5) is generally considered normal. Values above 3 Wood units suggest a meaningful pulmonary vascular component to any elevated pulmonary pressures, a threshold referenced in pulmonary hypertension classification guidelines.
PVR is typically calculated from measurements obtained during right-heart catheterization, where mean pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac output are all measured directly with a catheter, making PVR a hemodynamic (invasive) rather than purely echocardiographic value.
PVR helps distinguish pre-capillary pulmonary hypertension, where resistance in the small pulmonary arteries is elevated, from post-capillary pulmonary hypertension, which is driven mainly by elevated left-heart filling pressures. This distinction guides very different treatment approaches.
Wood units (named after Paul Wood) are the simpler clinical unit used at the bedside, while dynes.s.cm^-5 is the traditional CGS physical unit for resistance. One Wood unit equals 80 dynes.s.cm^-5, and this calculator shows both.
Yes — PVR can decrease meaningfully with pulmonary vasodilator therapy in some forms of pulmonary hypertension, and repeat catheterization is sometimes used to assess treatment response, a decision made by a treating cardiologist or pulmonologist.
Not necessarily — an elevated PVR can result from many different underlying conditions, including chronic lung disease, chronic thromboembolic disease, or left-heart disease, and the specific cause must be determined through a full clinical and hemodynamic workup.
PVR and cardiac output are inversely related in the resistance formula — for the same pressure gradient, a lower cardiac output produces a higher calculated PVR, so low-output states can sometimes elevate PVR even without a true increase in vascular resistance.
No — this tool is for informational and educational purposes only and performs the underlying PVR arithmetic. Diagnosis and management of pulmonary hypertension require full hemodynamic and clinical evaluation by a qualified healthcare provider.
PVR uses cardiac output directly, while the related Cardiac Index Calculator normalizes cardiac output to body surface area, giving a size-adjusted measure of overall heart function that's often reviewed alongside PVR during a full hemodynamic assessment.
Also known as