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A guided path through the Swan

Five steps, about ninety minutes in total: trust the measurement, know where you are, read the waveform, do the calculations, then practice. Already experienced? Every module is one click away below.

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  1. Step 1: Trust the measurement≈ 15 min

    Every later step assumes the number is real. Zero, level, damping, respiration and wedge quality decide that.

    By the end you can

    • Zero and level the transducer, and predict the error if it is wrong.
    • Tell an optimal, over-damped and under-damped trace with the fast-flush test.
    • Separate the two timing decisions: where in the respiratory cycle (end-expiration or an average) and where in the cardiac cycle (mean or end-diastolic).
    • Recognize a real wedge and the signatures of an incomplete or over-wedge.

  2. Step 2: Know where the catheter is≈ 10 min

    Pressures only mean something once you know the chamber. Diastole, not systole, tells RV from PA.

    By the end you can

    • Name the landmarks: RA about 20 cm, RV 30–35, PA 40–45, wedge about 50 (right IJ).
    • Identify RA, RV, PA and wedge from the shape of the trace, especially diastole.
    • Know what to do when the expected trace does not appear.

  3. Step 3: Read the waveform≈ 20 min

    A mean pressure is one number; the shape tells you about rhythm, valves and pericardial disease.

    By the end you can

    • Link a, c, v, x and y to the ECG and to the mechanical event behind each.
    • Recognize AF, AV dissociation, TR, TS, constriction, restriction and tamponade.
    • Explain why the mean wedge and the end-diastolic wedge are different measurements.

  4. Step 4: Do the calculations≈ 20 min

    Now the numbers can be trusted and located, so you can derive and interpret them with the formulas in view.

    By the end you can

    • Enter measured pressures and cardiac output, and read CI, PVR, SVR and the PH classification with their formulas.
    • Know which cardiac-output method is in use (thermodilution, direct Fick, estimated Fick) and why it matters.
    • Notice that reference ranges, diagnostic criteria, prognostic cutoffs and teaching frameworks are different things.

  5. Step 5: Practice with cases≈ 25 min

    Commit to an answer before you see the key; confidence and next-step questions show what you would actually do.

    By the end you can

    • Interpret a blinded case: filling pressures, output, PH class, RV involvement, grid label.
    • Say how sure you are, and what single measurement would settle it.
    • Compare with the closest competing diagnosis.
You cannot interpret a number you cannot trust, a trace whose chamber you cannot name, or a calculation whose inputs you do not understand. The guided path follows that dependency; the modules do not require it.

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