Rp/Rs Ratio (Pulmonary/Systemic Resistance) Calculator

Rp/Rs Ratio (Pulmonary/Systemic Resistance): Explanation and Clinical Context The Rp/Rs ratio represents the relative resistance of the pulmonary circulation (PVR) to the systemic circulation (SVR). It is calculated as the pulmonary vascular resistance divided by the systemic vascular resistance, providing insight into the balance between pulmonary and systemic vascular loads. A normal Rp/Rs ratio is typically less than 0.3, indicating that pulmonary resistance is significantly lower than systemic resistance.

Elevated Rp/Rs ratios (>0.3) may indicate pulmonary vascular disease, pulmonary hypertension, or maladaptive pulmonary circulation, which can be critical in congenital heart disease, especially in patients with left-to-right shunts. This ratio is used to guide clinical decision-making regarding operability in congenital heart defects, assessment of pulmonary hypertension severity, and monitoring response to medical or surgical interventions.