Practice Case C26

Pump suction

Diagnose a microaxial pump running faster than the ventricle can be filled and resolve it.

Experiment: Normal adult at rest · unchanged from its starting state

Key measurements

Pump suction present

— % of beat

baseline not set

Native aortic output

— L/min

baseline not set

— L/min

baseline not set

— mmHg

baseline not set

— mmHg

baseline not set

Inspect beats and technical detailsbeat selection, transient versus settled, timings

Position within the beat0.000 s

Early beats after a change are transient: the circulation is still re-balancing. A beat is called settled when three consecutive windows agree within the tolerance. Playback speed only moves the cursor over the finished simulation; it never changes the heart rate.

Compare scenariosbaseline, snapshots, axes, export

Baseline

No baseline is set.

Comparison snapshots

Keep up to three snapshots of states you want to compare with the baseline and the current state.

How comparisons are drawn

Side-by-side loops instead of an overlay Identical axes for every loop (turn off and each plot rescales to its own data)

Pressure–volume loop options

Show the ESPVR and EDPVR reference lines Shade stroke work Show the arterial elastance (Ea) line Show the right heart instead of the left

Export

Jump to the graph ↓

Presentation. RV failure after a large infarct; an LV microaxial pump at full speed is alarming for suction and its flow is below the set point.

Inspect

Read the suction fraction, pump flow, LV and RA pressure. Which side of the heart limits pump inflow?

Sources & model detailsreview status, testing, limitations

Sources

Content review

Teaching text and answer keys: Proposed. None of the 2 source claims behind it has been expert reviewed. Where a question has more than one defensible answer, more than one is accepted.

Simulation testing

Finding Hemo closed-loop lumped-parameter model: Quantitatively tested. Software, conservation and qualitative pattern tests pass. Not expert reviewed; normal ranges and phenotype parameter sets are proposed teaching values.
Scenario “Normal adult at rest” is checked for: closed-system volume conservation (<0.1% over 100 beats); timestep sensitivity (<1% change in core stable measurements at dt/2); seeded repeatability; resting pressures, volumes and flows within stated textbook ranges; directional response to fluid bolus and afterload increase.

Passing these tests means the equations are solved correctly and behave as stated. It does not mean the teaching statements, parameter values or answer keys have been expert reviewed.

Limitations that matter here

Reflexes are off: no autonomic compensation follows a change (the optional baroreflex is not enabled).
Constant intrathoracic pressure -3 mmHg (respiratory swing disabled).

Technical details

Model: fh-closed-loop 0.4.0
App / content version: 0.5.0 / 0.5.0
Scenario id: normal-adult
Solver: rk4, dt 0.2 ms
Case id: C26
Case version: 0.4.0
Model version at authoring: 0.4.0
Seed: 1
Parameter overrides: none