In vitro hemocompatibility investigation for the development of low-flow centrifugal blood pumps with less platelet clogging

Low-flow blood pumps rated under 1 L/min are emerging for new medical applications, such as hemofiltration in acute use. In those pumps, platelet adhesion and aggregation have to be carefully considered because of clogging risk in the filter part. To find an acceptable hemocompatibility that can be applied to low-flow centrifugal blood pump design, the platelet aggregation index, clogging on a micromesh filter, and the hemolysis index were investigated using a low-flow blood pump designed for hemofiltration use. We conducted circulation testing in vitro using fresh porcine blood and two centrifugal pumps with different impeller inlet shapes. The Negative Log Platelet Aggregation Threshold Index (NL-PATI), which reflects the ability of residual platelets to aggregate, and flow rate were measured during reflux for 60 min, and the Normalized Index of Hemolysis (NIH (g/20 min)) was calculated. In addition, blood cell clogging after reflux was observed on the micromesh filter by SEM, and the adhesion rate was calculated. Our results showed that the platelet clogging on the micromesh filter occurred when the average NL-PATI was greater than 0.28 and the average NIH (g/20 min) was greater than 0.01. In contrast, platelet clogging on the micromesh was suppressed when NL-PATI was less than 0.17 and the NIH (g/20 min) was less than 0.003. These values might be used as acceptable hemocompatibility of low-flow centrifugal blood pumps with suppressed platelet clogging for hemofiltration pumps.

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Hemolysis generation from a novel, linear positive displacement blood pump for cardiopulmonary bypass on a six kilogram piglet: a preliminary report

Perfusion ◽

10.1177/0267659116679881 ◽

2016 ◽

Vol 32 (4) ◽

pp. 264-268

Author(s):

D. Scott Lawson ◽

Derek Eilers ◽

Suzanne Osorio Lujan ◽

Maria Bortot ◽

James Jaggers

Keyword(s):

Cardiopulmonary Bypass ◽

Surface Area ◽

Preliminary Report ◽

Blood Pump ◽

Centrifugal Pumps ◽

Clinical Value ◽

Pump Design ◽

Positive Displacement ◽

Blood Pumps ◽

Extracorporeal Circuits

Background: Current blood pumps used for cardiopulmonary bypass generally fall into two different pump design categories; non-occlusive centrifugal pumps and occlusive, positive-displacement roller pumps. The amount of foreign surface area of extracorporeal circuits correlates with post-operative morbidity due to systemic inflammation, leading to a push for technology that reduces the amount of foreign surfaces. Current roller pumps are bulky and the tubing forms an arc in the pumping chamber (raceway), positioning the inlet 360 degrees from the outlet, making it very difficult to place the pump closer to the patient and to efficiently reduce tubing length. These challenges put existing roller pumps at a disadvantage for use in a compact cardiopulmonary bypass circuit. Centrifugal blood pumps are easier to incorporate into miniature circuit designs. However, the prime volumes of current centrifugal pump designs are large, especially for pediatric extracorporeal circuits where the prime volumes are too great to be of clinical value. Method: We describe a preliminary report on a novel, occlusive, linear, single-helix, positive-displacement blood pump which allows for decreased prime volume and surface area of the extracorporeal circuit. This new experimental pump design was used to perfuse a 6 kilogram piglet with a pediatric cardiopulmonary bypass circuit for two hours of continuous use. Blood samples were obtained every thirty minutes and assayed for plasma free hemolysis generation. Conclusions: The results from this initial experiment showed low plasma free hemoglobin generation and encourages the authors to further develop this concept.

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Hemolysis at low blood flow rates: in-vitro and in-silico evaluation of a centrifugal blood pump

Journal of Translational Medicine ◽

10.1186/s12967-020-02599-z ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Malte Schöps ◽

Sascha H. Groß-Hardt ◽

Thomas Schmitz-Rode ◽

Ulrich Steinseifer ◽

Daniel Brodie ◽

...

Keyword(s):

Blood Flow ◽

In Silico ◽

Fluid Dynamic ◽

High Flow ◽

Low Flow ◽

Bleeding Complications ◽

Centrifugal Pumps ◽

Operating Characteristics ◽

Centrifugal Blood Pump

Abstract Background Treating severe forms of the acute respiratory distress syndrome and cardiac failure, extracorporeal membrane oxygenation (ECMO) has become an established therapeutic option. Neonatal or pediatric patients receiving ECMO, and patients undergoing extracorporeal CO2 removal (ECCO2R) represent low-flow applications of the technology, requiring lower blood flow than conventional ECMO. Centrifugal blood pumps as a core element of modern ECMO therapy present favorable operating characteristics in the high blood flow range (4 L/min–8 L/min). However, during low-flow applications in the range of 0.5 L/min–2 L/min, adverse events such as increased hemolysis, platelet activation and bleeding complications are reported frequently. Methods In this study, the hemolysis of the centrifugal pump DP3 is evaluated both in vitro and in silico, comparing the low-flow operation at 1 L/min to the high-flow operation at 4 L/min. Results Increased hemolysis occurs at low-flow, both in vitro and in silico. The in-vitro experiments present a sixfold higher relative increased hemolysis at low-flow. Compared to high-flow operation, a more than 3.5-fold increase in blood recirculation within the pump head can be observed in the low-flow range in silico. Conclusions This study highlights the underappreciated hemolysis in centrifugal pumps within the low-flow range, i.e. during pediatric ECMO or ECCO2R treatment. The in-vitro results of hemolysis and the in-silico computational fluid dynamic simulations of flow paths within the pumps raise awareness about blood damage that occurs when using centrifugal pumps at low-flow operating points. These findings underline the urgent need for a specific pump optimized for low-flow treatment. Due to the inherent problems of available centrifugal pumps in the low-flow range, clinicians should use the current centrifugal pumps with caution, alternatively other pumping principles such as positive displacement pumps may be discussed in the future.

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Flow characteristics and hemolytic performance of the new Breethe centrifugal blood pump in comparison with the CentriMag and Rotaflow pumps

The International Journal of Artificial Organs ◽

10.1177/03913988211041635 ◽

2021 ◽

pp. 039139882110416

Author(s):

Ge He ◽

Jiafeng Zhang ◽

Aakash Shah ◽

Zachary B Berk ◽

Lu Han ◽

...

Keyword(s):

Experimental Data ◽

Shear Stress ◽

Flow Characteristics ◽

Pressure Head ◽

Blood Pump ◽

Assisted Circulation ◽

Centrifugal Blood Pump ◽

Blood Pumps ◽

Flow Features

Blood pumps have been increasingly used in mechanically assisted circulation for ventricular assistance and extracorporeal membrane oxygenation support or during cardiopulmonary bypass for cardiac surgery. However, there have always been common complications such as thrombosis, hemolysis, bleeding, and infection associated with current blood pumps in patients. The development of more biocompatible blood pumps still prevails during the past decades. As one of those newly developed pumps, the Breethe pump is a novel extracorporeal centrifugal blood pump with a hybrid magnetic and mechanical bearing with attempt to reduce device-induced blood trauma. To characterize the hydrodynamic and hemolytic performances of this novel pump and demonstrate its superior biocompatibility, we use a combined computational and experimental approach to compare the Breethe pump with the CentriMag and Rotaflow pumps in terms of flow features and hemolysis under an operating condition relevant to ECMO support (flow: 5 L/min, pressure head: ~350 mmHg). The computational results showed that the Breethe pump has a smaller area-averaged wall shear stress (WSS), a smaller volume with a scalar shear stress (SSS) level greater than 100 Pa and a lower device-generated hemolysis index compared to the CentriMag and Rotaflow pumps. The comparison of the calculated residence times among the three pumps indicated that the Breethe pump might have better washout. The experimental data from the in vitro hemolysis testing demonstrated that the Breethe pump has the lowest normalized hemolysis index (NIH) than the CentriMag and Rotaflow pumps. It can be concluded based on both the computational and experimental data that the Breethe pump is a viable pump for clinical use and it has better biocompatibility compared to the clinically accepted pumps.

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Disposable Magnetically Levitated Centrifugal Blood Pump: Design and In Vitro Performance

Artificial Organs ◽

10.1111/j.1525-1594.2005.29087.x ◽

2005 ◽

Vol 29 (7) ◽

pp. 520-526 ◽

Cited By ~ 20

Author(s):

Hideo Hoshi ◽

Junichi Asama ◽

Tadahiko Shinshi ◽

Katsuhiro Ohuchi ◽

Makoto Nakamura ◽

...

Keyword(s):

Blood Pump ◽

Centrifugal Blood Pump ◽

Pump Design ◽

Magnetically Levitated ◽

In Vitro Performance

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Effect of blade curvature on the hemolytic and hydraulic characteristics of a centrifugal blood pump

The International Journal of Artificial Organs ◽

10.1177/0391398818785558 ◽

2018 ◽

Vol 41 (11) ◽

pp. 730-737 ◽

Cited By ~ 3

Author(s):

Caglar Ozturk ◽

I Basar Aka ◽

Ismail Lazoglu

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

In Silico ◽

Estimation Method ◽

Computational Method ◽

Blood Pump ◽

Centrifugal Blood Pump ◽

Pump Design ◽

Straight Blade

Aims: Impeller design has a significant impact on the overall performance of a blood pump. In this study, the effect of the blade curvature was investigated by performing in silico and in vitro studies on a recently developed centrifugal blood pump. Methods: A computational fluid dynamics study was performed for the flow rates of 3–5 L/min at 2000 r/min. The computational fluid dynamics model was also applied on the US Food and Drug Administration (FDA) benchmark blood pump to validate our computational method. The relative hemolysis index was calculated with the Eulerian hemolysis estimation method for five impellers with the wrap angles ranging from 0° to 240°. Hydraulic experiments were conducted for the validation of computational fluid dynamics results. In addition, the curved-blade impeller (120°) and the straight-blade impeller (0°) were evaluated with in vitro hemolysis tests using human blood. Results: The wrap angle of 120° provided the best hydraulic and hemolytic performance. Pump achieved the physiologic operating pressures and flows with 85–115 mmHg at 2.5–5.9 L/min. Compared to the straight-blade impeller, the 120° model reduces the relative hemolysis index and the plasma-free hemoglobin near 72.8% and 56.7%, respectively. Comparison of in silico and in vitro results indicated the similar trend to the blade curvature. Conclusion: Introducing a blade curvature enhanced the hydrodynamic and hemolytic performance compared to the straight-blade configuration for the investigated centrifugal blood pump. The findings of this study provide new insights into centrifugal blood pump design by examining the influence of the blade curvature.

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