Testing and Validation of Reciprocating Positive Displacement Pump for Benchtop Pulsating Flow Model of Cerebrospinal Fluid Production and Other Physiologic Systems

Abstract

Background: The flow of physiologic fluids through organs and organs systems is an integral component of their function. The complex fluid dynamics in many organ systems are still not completely understood, and in-vivo measurements of flow rates and pressure provide a testament to the complexity of each flow system. Variability in in-vivo measurements and the lack of control over flow characteristics leave a lot to be desired for testing and evaluation of current modes of treatments as well as future innovations. In-vitro models are particularly ideal for studying neurological conditions such as hydrocephalus due to their complex pathophysiology and interactions with therapeutic measures. The following aims to present the reciprocating positive displacement pump, capable of inducing pulsating flow of a defined volume at a controlled beat rate and amplitude. While the other fluidic applications of the pump are currently under investigation, this study was focused on simulating the pulsating cerebrospinal fluid production across profiles with varying parameters. Methods: Pumps were manufactured using 3D printed and injection molded parts. The pumps were powered by an Arduino-based board and proprietary software that controls the linear motion of the pumps to achieve the specified output rate at the desired pulsation rate and amplitude. A range of 0.01 to 0.7 was tested to evaluate the versatility of the pumps. The accuracy and precision of the pumps’ output were evaluated by obtaining a total of 150 one-minute weight measurements of degassed deionized water per output rate across 15 pump channels. In addition, nine experiments were performed to evaluate the pumps’ control over pulsation rate and amplitude. Results: volumetric analysis of a total of 1200 readings determined that the pumps achieved the target output volume rate with a mean absolute error of -0.001034283 across the specified domain. It was also determined that the pumps can maintain pulsatile flow at a user-specified beat rate and amplitude. Conclusion: The validation of this reciprocating positive displacement pump system allows for the future validation of novel designs to components used to treat hydrocephalus and other physiologic models involving pulsatile flow. Based on the promising results of these experiments at simulating pulsatile CSF flow, a benchtop model of human CSF production and distribution could be achieved through the incorporation of a chamber system and a compliance component

The Development and Validation of a Portable, Benchtop, Hydrostatic Model to Acquire and Analyze Quantitative Data on Unused and Failed Hydrocephalus Catheters

“…Benchtop pump systems can simulate CSF flow with varying parameters and high precision and have been proposed as potential components of in vitro hydrocephalus models. 20 Finally, the manually obstructed catheter was obstructed using glue, which is notably different from being obstructed by human cells. Future experiments with manually obstructed shunts can use human astrocyte cultures to plug the hole interfaces, providing a more accurate shunt obstruction model.…”

Applications of a novel reciprocating positive displacement pump in the simulation of pulsatile arterial blood flow

“…In our setup, the simple silicone tubing system used alongside the reciprocating positive-displacement pump allows for a vast array of fluids with physiologic or pathophysiologic makeup. An example fluid explored in the previous literature is cerebrospinal fluid (CSF), where the reciprocating positive displacement pump can be used to model pulsatile flow, shear rate, shear stress, and amplitude simultaneous to variations in CSF composition as this is directly relevant to pathologic states like those in hydrocephalus [ 33 , 34 ].…”

Applications of a Novel Reciprocating Positive Displacement Pump in the Simulation of Pulsatile Arterial Blood Flow

“…In our previous study, the accuracy of the reciprocating positive displacement pump was demonstrated across a range of 0.01ml/min to 0.7ml/min with an R 2 value of 0.9998[5]. To expand the verified flow rate range and investigate the capabilities of the pump in novel applications of arterial blood flow in organ systems, a literature search was conducted collecting flow rate data spanning three ranges; low (0ml/min – 0.4ml/min), mid (0.4ml/min – 1.5ml/min) and high (3ml/min – 16ml/min) bulk flow rates.…”

“…In our setup, the simple silicone tubing system used alongside the reciprocating positive-displacement pump allows for a vast array of fluids with physiologic or pathophysiologic makeup. An example fluid explored in the previous literature is cerebrospinal fluid (CSF), where the reciprocating positive displacement pump can be used to model pulsatile flow, shear rate, shear stress, and amplitude simultaneous to variations in CSF composition as this is directly relevant to pathologic states like those in hydrocephalus [5,29].…”