Qp:Qs Shunt Quantification

Pulmonary-to-Systemic Flow Ratio & Hemodynamic Volume Assessment

Velocity Time Integrals & Diameters

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Enter complete outflow velocities and dimensions above to calculate active shunt values.
Qp:Qs Ratio
Shunt Status Physiologic Normal Balance Small Left-to-Right Shunt (Insignificant) Moderate Left-to-Right Shunt (Significant) Large Left-to-Right Shunt (Severe Overload) Reversed Shunt (Eisenmenger Risk)
LVOT:RVOT VTI Ratio
Systemic Stroke Volume (Qs)
Pulmonary Stroke Volume (Qp)

Clinical Pathophysiology & Calculation Methods

The Qp:Qs Ratio balances total blood flow moving through the pulmonary systemic pathway against matching outputs driving the peripheral systemic circulation. In normal anatomical pathways, this values remains exactly balanced at 1.0.

This metric serves as a quantitative gold standard when tracing congenital anomalies including Patent Ductus Arteriosus (PDA), Ventricular Septal Defects (VSD), and Atrial Septal Defects (ASD). Left-to-right vascular communications volume-overload the downstream structures, and a ratio exceeding 1.5 commonly represents a strong indication for definitive device occlusion or surgical correction to counteract irreversible remodelling changes.

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