Academic chairs
Medical engineering, fluid mechanics or cardiovascular technology — with an existing circulatory test bench.
Seeking laboratory access for the next validation stage.
Three modules are manufactured and a circulatory bench loop is built and running. The next step requires an environment that cannot be built privately — and partners who work with blood, circulation and measurement.
SINCE 2017BENCH LOOP RUNNING15.6 L/MIN
Project status
Three modules exist as manufactured hardware: the pulsatile membrane chamber for the systemic circuit, the microaxial pump for the pulmonary circuit, and the pulse chamber. They were produced additively, from standard components and by hand.
A circulatory bench loop is built and in operation. It has circulated fluid at blood-like viscosity.
The sensing system is built and in operation: flow, pressure and oxygenation, on both sides and before and after each inlet, plus preload and afterload. It is the prerequisite for balancing the systemic and pulmonary circuits against each other.
Energy storage, battery management and inductive charging exist as concept and design work, not as hardware.
Six to fifteen design revisions have been produced since 2017. The work is done alongside employment, at 15 to 30 hours per week.
In earlier phases, the concept was discussed with Prof. Dr. Christoph Bode, former Medical Director of the Department of Cardiology and Angiology at Freiburg University Medical Center.
Design and control range
Both chambers run on a single drive, so their volume ratio is fixed by geometry. Control acts through stroke, rate and the continuously variable pump.
| Quantity | Value |
|---|---|
| Systemic chamber, maximum output | 130 ml |
| Pulse chamber, pulmonary circuit | 30 ml |
| Continuous pump, pulmonary circuit | 0–12 l/min, continuously variable |
| Beat rate | 40–150 /min |
| System output at full stroke | 15.6 l/min at 120 /min |
| System output at reduced stroke | up to 16.5 l/min at 150 /min |
| Turndown ratio | better than 10 : 1 |
The systemic and pulmonary circuits are in series and must deliver the same volume. Because the chambers are coupled, the required continuous-pump flow follows directly from stroke minus pulse-chamber volume, times rate. At full stroke the continuous pump reaches its ceiling at 120 beats — that is the design point.
What is measured — and what is not
This distinction is deliberate and applied consistently. Every figure in the technical dossier is a design target, not a validated measurement.
| Quantity | Status |
|---|---|
| Pressure | measured on the bench |
| Temperature | measured on the bench |
| Runtime and endurance | measured on the bench |
| Volumetric flow | derived by calculation — not measured |
| Mean arterial pressure | calculated from systolic and diastolic |
| Operation at blood-like viscosity | achieved, with model fluid |
| Haemolysis and blood compatibility | open — no blood testing performed |
| Flow simulation (CFD) | not performed |
| Structural simulation (FEA) | not performed |
| Standards-compliant testing | open |
Why pulsatile
Current support systems mostly use rotary pumps at 20,000 to 50,000 revolutions per minute. Reduced pulsatility there is associated with acquired von Willebrand syndrome, bleeding from arteriovenous malformations and aortic insufficiency; the cause is destruction of high-molecular-weight von Willebrand multimers by shear.
This displacement pump operates at roughly 2 Hz — four orders of magnitude fewer cycles and correspondingly lower shear. That is a design rationale, not a claim of efficacy.
Pulsatility also matters demonstrably for the pulmonary circuit: in the Fontan and Glenn circulation, where the lung is perfused without pulsation, impaired endothelial function, reduced nitric oxide availability and rising pulmonary vascular resistance are documented.
What is being sought
The next development step is a measurement series using animal blood: behaviour under real viscosity and cellular loading rather than model fluid. Laboratory access and a measurement environment are what is missing.
- Access to a circulatory test bench or perfusion laboratory
- The ability to work with animal blood — anticoagulation, cold chain, proper disposal
- Time-resolved flow measurement, so that pressure and flow can be evaluated together
- Specialist guidance on haemocompatibility and flow measurement
- In due course: flow simulation and standards-compliant testing
With access in place, six to eighteen months to meaningful data is a realistic horizon.
Three open questions to work on
All three are bounded, workable on the existing bench, and not conclusively answered in the literature.
- At what ejection profile does a 30 ml stroke deliver maximum surplus hemodynamic energy without raising mean pulmonary arterial pressure above 20 mmHg? The pulmonary circuit leaves only a few mmHg of headroom before benefit turns into harm.
- At what stroke volume does pulmonary pulsatility become physiologically effective? No threshold is defined in the literature. Pulsatile cardiopulmonary bypass, at roughly 5,000 ergs/cm³ at the patient, serves as the reference figure.
- What ramp limit keeps the output control loop outside the baroreflex time constant without delaying demand response? Pump and body are two controllers acting on the same plant; overlapping time constants lead to hunting.
Who this is addressed to
Doctoral researchers
Anyone looking for a bounded, practically workable question for their own research.
Perfusion and cardiovascular technology
Practitioners with daily experience of extracorporeal circulation, pumps and blood.
Manufacturers
Medical device companies with their own development and testing infrastructure.
What the project brings
Eight years of prior work. Design, dimensioning, manufactured modules, installed sensing and a running bench loop. A partner does not start from zero, but at a point where the mechanics demonstrably operate.
Co-authorship. Results from joint work are published jointly.
Free use of results. The project pursues no commercial interest. The aim is technology that reaches people — not a protected portfolio.
Open points, stated explicitly
What is missing is listed here so that nobody has to ask for it:
- No flow or structural simulation has been performed
- No work to ISO 14971, IEC 60601 or ISO 5840 so far
- Volumetric flow is calculated and unvalidated
- No time-resolved flow measurement, and therefore no energy-based assessment of pulsatility
- No blood testing, no haemolysis data
- Form factor of the pulmonary pump not fixed
- Energy storage, battery management and inductive charging exist on paper only
- No institutional affiliation, no third-party funding
This is a preclinical research and development project. It is not an approved medical device, there is no clinical application, and no medical advice is given.
Contact
For technical enquiries, a direct message to info@kanzlerbiologicals.com is sufficient. The contact form is available for everything else.
Responses that contradict the project are equally welcome. A well-founded objection is worth more than agreement.