PDA · shunt & PA pressure calculator
Explore pda · shunt & pa pressure with the method’s inputs, acquisition guidance and source references. Open the calculator to enter measurements or try an illustrative worked example.
Method
Systolic ΔP = 4Vsys²; estimated PASP = SBP − ΔP; estimated mPAP = MAP − complete-cycle mean ΔP
Use the measurement units shown below. Some fields apply only to a selected method or condition; follow the interactive tool’s method choices. The interactive tool keeps missing measurements incomplete and provides its method-specific results and reference context.
Measurements and acquisition
Clinical question
Enter the measured value in the displayed unit
- PA systolic pressure
- Mean PA pressure
- Ductal gradient only
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Observed ductal flow
Enter the measured value in the displayed unit
- Not established
- All left → right
- Bidirectional
- All right → left
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.
Peak systolic PDA velocity m/s
Continuous-wave Doppler
- Align the CW cursor as parallel as possible to the jet.
- Acquire a dense, complete envelope without truncation.
- Measure the highest absolute velocity on the selected envelope.
Systolic blood pressure mmHg
Contemporaneous cuff or invasive value
- Use a pressure obtained in the same hemodynamic state as the echo.
- Confirm the value is entered in mmHg.
- Do not mix values acquired under different loading conditions.
Complete-cycle mean gradient mmHg
Complete traced CW envelope
- Align through the valve or shunt and record a complete envelope.
- Trace the modal velocity envelope using the machine tool.
- Use the machine-calculated mean gradient in mmHg.
Mean arterial pressure mmHg
Contemporaneous cuff or invasive value
- Use a pressure obtained in the same hemodynamic state as the echo.
- Confirm the value is entered in mmHg.
- Do not mix values acquired under different loading conditions.
Sources and method context
ASE · AHA / ACC · primary Doppler studies · 2025 · PDA acquisition, pressure estimation and whole-shunt assessment · ASE pediatric TTE 2024 pp. 162–163 · TNE 2024 pp. 185–188, Table 5 · Musewe et al. 1987
- Locate the duct and record the whole cycle · Lopez et al. JASE 2024;37:119–170 · pp. 162–163 · doi:10.1016/j.echo.2023.11.015
High parasternal sagittal and suprasternal color sweeps; assess restriction and direction throughout the cycle. Abdominal holodiastolic reversal has other causes.
- Conditional pressure estimates · Musewe et al. Circulation 1987;76:1081–1091 · PMID 2959394; Lu et al. 1991 · PMID 1806337
Small simultaneous Doppler/catheter studies support systolic and mean estimates in appropriate PDA flow. Right-to-left velocity did not correlate with pressure in the Musewe series; this tool restricts subtraction to continuous left-to-right flow.
- Geometry and timing limitations · Duct-geometry study 1987 · PMID 3329223; Spach et al. Circulation 1980;61:110–122 · doi:10.1161/01.CIR.61.1.110
Duct configuration can distort Bernoulli estimates; instantaneous pressure separation and shunt direction change during the cardiac cycle.
- Hemodynamic significance is multiparametric · ASE targeted neonatal echo 2024 · pp. 185–188, Table 5 p. 197 · doi:10.1016/j.echo.2023.11.016; 2025 ACHD guideline §4.1.5 · doi:10.1016/j.jacc.2025.09.006
Assess chamber/flow response and systemic runoff in their population context. Adult decisions incorporate net shunt, LV effects and PVR; no automated significance, PAH grade or closure recommendation is supplied.
Catalogue review status: Exact guideline locator mapped · clinical sign-off pending
These pages describe the educational tool. Interpret measurements with the complete clinical context and the method’s acquisition limitations.