From Bench Testing to Implantable Clinical Devices

Transonic’s versatile implementation of ultrasonic transit time technology provides the biomedical engineer with a set of reliable volume flow measurement tools that are used at every stage in the development of heart assist devices and blood pumps. The Flowsensors and Flowprobes meet these changing requirements as a project develops in:

Bench Testing

Pumps are first conceived and tested on the bench in tubing models that reproduce physiologic pressures and flow rates of the human circulatory system. Pulsatile and mean volume flow are important measurement parameters in determining the validity of the bench set up as well as the performance of the device in the circuit.

Transonic inline Flowsensors are spliced into the tubing circuit for an accurate flow measurement.The characteristics of the test fluid also impact the dynamics of the circuit and performance of the device. Therefore, various recipes, such as water and glycerine mixes are used to mimic the viscosity and density of blood. These are known as blood analogs. Transonic inline and sterile tubing Flowsensors can be calibrated for multiple specific blood analogs at various temperatures for the greatest accuracy and convenience to the engineer.

In Vivo Testing - PDF

Transonic implantable perivascular Flowprobes are also important in the preclinical stage of the device testing. Several different types of pump devices have been designed including total artificial heart replacements, implantable ventricular and biventricular assist devices, and extracorporeal assist devices. The efficacy of all of these must be tested in animal models that share the size and volume flow capacity of the human they are designed for. Long term implant studies are performed in calves and sheep; often with multiple Transonic perivascular flowprobes implanted on the pump outlet graft, the pulmonary artery, the ascending aorta, and various peripheral vessels or a coronary artery to determine the effectiveness of the pump in maintaining whole body circulation. These studies can run from 3 months to a year and rely on the continued accuracy and performance of Transonic Flowprobes. Custom calibration and programming of Transonic perivascular probes may apply to increase performance under specialized conditions.

“Transonic Inside” - OEM

The marriage between Transonic flow technology and pump devices does not end in the final stage of a clinical device. Transonic flow measurement technology has become an integral part of several clinical blood pumps that verify the volume flow delivered to the patient.

Publication References

VAD Development