Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist Device

Ventricular assist devices (VADs) are implantable turbomachines that save and improve the lives of patients with severe heart failure. In the preclinical evaluation, a VAD design must be experimentally or numerically tested regarding its pump characteristics, primarily for its pressure buildup (pres...

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Main Authors: Finn Knüppel, Inga Thomas, Frank-Hendrik Wurm, Benjamin Torner
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Fluids
Subjects:
Online Access:https://www.mdpi.com/2311-5521/8/5/151
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author Finn Knüppel
Inga Thomas
Frank-Hendrik Wurm
Benjamin Torner
author_facet Finn Knüppel
Inga Thomas
Frank-Hendrik Wurm
Benjamin Torner
author_sort Finn Knüppel
collection DOAJ
description Ventricular assist devices (VADs) are implantable turbomachines that save and improve the lives of patients with severe heart failure. In the preclinical evaluation, a VAD design must be experimentally or numerically tested regarding its pump characteristics, primarily for its pressure buildup (pressure head <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>H</mi></semantics></math></inline-formula>) since it must provide the cardiovascular system with a sufficient blood flow rate <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>Q</mi></semantics></math></inline-formula>. Those pump characteristics are determined on a test bench. Here, a glycerol-water mixture is almost exclusively used as blood-analogous fluid, which should reflect the properties (density, viscosity) of blood as close as possible. However, glycerol water has some disadvantages, such as a higher density compared to real blood and a relatively high cost. Therefore, the study aimed to analyze six different blood analogous fluids to select the most suitable one in consideration of fluid handling, costs, and, most importantly, fluid properties (material and rheological). First, all fluids were mixed to achieve reference values of blood density and viscosity from the literature. Afterwards, the pump characteristics (pressure heads and efficiencies via the VAD) were experimentally and numerically determined and compared among each other and with literature values. Of all six investigated fluids, only the aqueous–polyethylene glycol 200 (PEG 200) solution matches exactly the desired blood properties, and the pump characteristics of this fluid are in the expected range for the analyzed operation point of the VAD. Another advantage is that the cost of the mixture is 35% lower compared to glycerol water. Additionally, we demonstrate that non-Newtonian flow behavior has little effect on the pump characteristics in our VAD.
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spelling doaj.art-31c750d5d2314a76a85e449a9320e27a2023-11-18T01:20:22ZengMDPI AGFluids2311-55212023-05-018515110.3390/fluids8050151Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist DeviceFinn Knüppel0Inga Thomas1Frank-Hendrik Wurm2Benjamin Torner3Institute of Turbomachinery, University of Rostock, Albert-Einstein-Straße 2, 18059 Rostock, GermanyInstitute of Turbomachinery, University of Rostock, Albert-Einstein-Straße 2, 18059 Rostock, GermanyInstitute of Turbomachinery, University of Rostock, Albert-Einstein-Straße 2, 18059 Rostock, GermanyInstitute of Turbomachinery, University of Rostock, Albert-Einstein-Straße 2, 18059 Rostock, GermanyVentricular assist devices (VADs) are implantable turbomachines that save and improve the lives of patients with severe heart failure. In the preclinical evaluation, a VAD design must be experimentally or numerically tested regarding its pump characteristics, primarily for its pressure buildup (pressure head <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>H</mi></semantics></math></inline-formula>) since it must provide the cardiovascular system with a sufficient blood flow rate <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>Q</mi></semantics></math></inline-formula>. Those pump characteristics are determined on a test bench. Here, a glycerol-water mixture is almost exclusively used as blood-analogous fluid, which should reflect the properties (density, viscosity) of blood as close as possible. However, glycerol water has some disadvantages, such as a higher density compared to real blood and a relatively high cost. Therefore, the study aimed to analyze six different blood analogous fluids to select the most suitable one in consideration of fluid handling, costs, and, most importantly, fluid properties (material and rheological). First, all fluids were mixed to achieve reference values of blood density and viscosity from the literature. Afterwards, the pump characteristics (pressure heads and efficiencies via the VAD) were experimentally and numerically determined and compared among each other and with literature values. Of all six investigated fluids, only the aqueous–polyethylene glycol 200 (PEG 200) solution matches exactly the desired blood properties, and the pump characteristics of this fluid are in the expected range for the analyzed operation point of the VAD. Another advantage is that the cost of the mixture is 35% lower compared to glycerol water. Additionally, we demonstrate that non-Newtonian flow behavior has little effect on the pump characteristics in our VAD.https://www.mdpi.com/2311-5521/8/5/151blood-analogous fluidblood pumpventricular assist devicepump characteristicspressure headefficiency
spellingShingle Finn Knüppel
Inga Thomas
Frank-Hendrik Wurm
Benjamin Torner
Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist Device
Fluids
blood-analogous fluid
blood pump
ventricular assist device
pump characteristics
pressure head
efficiency
title Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist Device
title_full Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist Device
title_fullStr Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist Device
title_full_unstemmed Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist Device
title_short Suitability of Different Blood-Analogous Fluids in Determining the Pump Characteristics of a Ventricular Assist Device
title_sort suitability of different blood analogous fluids in determining the pump characteristics of a ventricular assist device
topic blood-analogous fluid
blood pump
ventricular assist device
pump characteristics
pressure head
efficiency
url https://www.mdpi.com/2311-5521/8/5/151
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AT frankhendrikwurm suitabilityofdifferentbloodanalogousfluidsindeterminingthepumpcharacteristicsofaventricularassistdevice
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