Elsevier

Medical Engineering & Physics

Volume 77, March 2020, Pages 118-124
Medical Engineering & Physics

Technical Note
Pulsatile flow pump based on an iterative controlled piston pump actuator as an in-vitro cardiovascular flow model

https://doi.org/10.1016/j.medengphy.2019.10.020Get rights and content

Highlights

  • Pulsatile pump is used to simulate pulsatile flow in several in-vitro experiments.

  • The desired physiological flow need to be output accurately in some experiments.

  • The developed pulsatile pump minimized the error through iterative control algorithm.

Abstract

In-vitro cardiovascular experiments provide an effective means for characterizing structural or hemodynamic features of medical devices before they are tested on animals or used in clinical practice. In-vitro experiments simulate complicated cardiovascular systems with blood pumps, vessels and valves, but without human or animal subjects. Therefore, such experiments are free from ethical issues and present large cost savings in comparison to in-vivo experiments. In this study, we aimed to design a fully programmable pulsatile flow pump that can consistently and accurately reproduce a wide range of physiological flow waveforms without costly transient flowmeter in the system. An iterative control algorithm (ICA) was used to minimize the differences between the desired and produced flow waveforms. Our results confirm that the developed pulsatile pump can replicate flow waveforms accurately, with root mean square errors (RMSEs) of 0.64 L/min and 0.52 mL for the flow rate and stroke volume, respectively.

Section snippets

Background

Despite their widespread use in the treatment of cardiovascular disease, stents, prosthetic aortic valves and ventricular assist devices (VADs) may lead to serious side-effects, frequently associated with abnormal hemodynamics. Stent implantation has been found to affect local hemodynamics, and the altered hemodynamics in turn significantly affect the proliferation of endothelial cells in the vessel [1]. Furthermore, stent insertion increases the in-stent peak systolic velocity and reduces

Pump design

We constructed our pump system using a cylindrical acrylic chamber, a piston, a linear actuator (PC40; Thomson Industries, Inc., Radford, VA, USA), a brushless direct current (BLDC)-based servomotor (AKM44Hsingle bondHNCNR-00; Kollmorgen Corporation, Radford, VA, USA), and a motor driver (AKD-B00306-NAAN; Kollmorgen Corporation), as shown in Figure 1. The working fluid was water with a constant density of 997 kg/m3 and dynamic viscosity of 8.899 × 10−4 kg/m s. Cylindrical chambers were constructed with an

Results

When a step signal was input to the piston pump, the ejection of the pump was found to have a delay time of approximately 0.2 s relative to the input signal. We carried out a correlation analysis to verify whether the displacement output signal of the pump matched the actual piston position observed by the camera and found that the two values were highly correlated. The correlations between the motor displacement signals and camera images were as follows: y = 1.02x–1.23 (r2 = 0.99) at 40 mL, y

Discussion

In this study, we developed a pulsatile pump using a servomotor, DAQ and piston; the main results were as follows: (a) the developed system replicated physiological blood flow waveforms and is thus suitable for in-vitro cardiovascular experiments; and (b) the replicated flow waveforms had an accuracy (RMSE) of 0.64 L/min and 0.52 mL for the flow rate and stroke volume, respectively.

In this study, we developed an affordable and programmable pump. The total cost of the system is approximately

Conclusion

The major contributions of this study are as follows: (a) manufacture of a pulsatile pump controlled by a computer and analogue voltage input using a piston, (b) reconstruction of physiological blood flow waveforms in living bodies using a pulsatile pump, and (c) reductions in the final RMSEs of flow rate and stroke volume to 0.64 L/min and 0.52 mL, respectively, using the IF algorithm.

Declaration of Competing Interest

The authors declare that they have no competing interests.

Declarations

JK analysed the data and wrote the draft manuscript. YL fabricated the pump system. SC analysed the data and wrote the draft manuscript. HH suggested ideas and motivations for this study and supervised all details of the research. All authors read and approved the final manuscript.

Ethical approval

Not required.

Data availability

All datasets analysed during the current study are only available from the corresponding author on reasonable request.

Funding statement

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (NRF-2018R1D1A1A02043249). This study was also supported by a 2018 Research Grant from Kangwon National University (D1001679-01-01).

Acknowledgements

We thank Woo-Jin Choi, 3DMD, South Korea, for kindly advising the design and fabrication of the pump system.

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