About the PVR Calculator - Pulmonary Vascular Resistance
Pulmonary vascular resistance (PVR) is a hemodynamic measurement that quantifies the resistance the right side of the heart works against to push blood through the lungs. It is derived from three values normally obtained during right heart catheterization: mean pulmonary artery pressure (mPAP), pulmonary capillary wedge pressure (PCWP, a surrogate for left atrial pressure), and cardiac output (CO). The standard formula is PVR = (mPAP − PCWP) ÷ CO, giving a result in Wood units (mmHg·min/L), which can be converted to dyn·s·cm⁻⁵ by multiplying by 80.
How to get accurate results
- Enter mean pulmonary artery pressure and pulmonary capillary wedge pressure in mmHg exactly as reported from catheterization — do not substitute systolic or diastolic PAP.
- Cardiac output should be the measured value (thermodilution or Fick method) in L/min, not cardiac index.
- Body surface area (BSA) is only used to compute the indexed PVR (PVRI); use the patient's actual BSA in m² if you want that figure to be meaningful.
Putting the result in context
A PVR below 2 Wood units is generally normal. Values from 2 to 3 Wood units are borderline and warrant correlation with the rest of the hemodynamic picture. A PVR above 3 Wood units is the threshold referenced in pulmonary hypertension guidelines as indicating clinically significant pulmonary vascular disease. These are population-based cutoffs, not a diagnosis on their own.
When to consult a professional
This calculator performs the arithmetic only — it does not interpret your full clinical picture, account for measurement error in the catheterization data, or provide dosing or treatment advice. Any PVR result, especially one near or above the elevated threshold, should be reviewed with a cardiologist or pulmonologist alongside the complete hemodynamic and clinical assessment.