The Sealless and Bearingless Rotor Blood Pump System: Adaptation to the Circulatory System and In Vitro Advantages in Efficiency, Flow Characteristics, and Boundary Conditions of Thermal Heat Up

1989 ◽  
pp. 215-224 ◽  
Author(s):  
G. Bramm ◽  
D. B. Olsen
Keyword(s):  
Boundary Conditions ◽  
Circulatory System ◽  
Flow Characteristics ◽  
Blood Pump ◽  
Pump System ◽  
System Adaptation

IN VITRO PERFORMANCE EVALUATION OF NEW DESIGNED MAGNETIC LEVITATED DISPOSABLE EXTRACORPOREAL CENTRIFUGAL BLOOD PUMP SYSTEM

ASAIO Journal ◽  
2006 ◽  
Vol 52 (2) ◽  
pp. 23A
Author(s):  
Hideo Hoshi ◽  
Junichi Asama ◽  
Chikara Hara ◽  
Wataru Hijikata ◽  
Tadahiko Shinshi ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Blood Pump ◽  
Pump System ◽  
Centrifugal Blood Pump ◽  
In Vitro Performance

IN VITRO DURABILITY TEST OF THE CENTRIFUGAL BLOOD PUMP SYSTEM UNDER PULSATILE CONDITIONS

ASAIO Journal ◽  
2003 ◽  
Vol 49 (2) ◽  
pp. 150
Author(s):  
T Kitano ◽  
T Tokuno ◽  
K Yamazaki ◽  
S Kihara ◽  
M Umezu ◽  
...  
Keyword(s):  
Blood Pump ◽  
Durability Test ◽  
Pump System ◽  
Centrifugal Blood Pump

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

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.

scholarly journals In vitro testing of explanted shunt valves in hydrocephalic patients with suspected valve malfunction

2021 ◽  
Author(s):  
Christoph Bettag ◽  
Christian von der Brelie ◽  
Florian Baptist Freimann ◽  
Ulrich-Wilhelm Thomale ◽  
Veit Rohde ◽  
...  
Keyword(s):  
Flow Rate ◽  
Clinical Symptoms ◽  
Obstructive Hydrocephalus ◽  
Flow Characteristics ◽  
Normal Pressure ◽  
Diagnostic Tools ◽  
Programmable Valve ◽  
Significant Difference ◽  
Valve Malfunction

AbstractDiagnosis of symptomatic valve malfunction in hydrocephalic patients treated with VP-Shunt (VPS) might be difficult. Clinical symptoms such as headache or nausea are nonspecific, hence cerebrospinal fluid (CSF) over- or underdrainage can only be suspected but not proven. Knowledge concerning valve malfunction is still limited. We aim to provide data on the flow characteristics of explanted shunt valves in patients with suspected valve malfunction. An in vitro shunt laboratory setup was used to analyze the explanted valves under conditions similar to those in an implanted VPS. The differential pressure (DP) of the valve was adjusted stepwise to 20, 10, 6, and 4 cmH2O. The flow rate of the explanted and the regular flow rate of an identical reference valve were evaluated at the respective DPs. Twelve valves of different types (Codman CertasPlus valve n = 3, Miethke Shuntassistant valve n = 4, Codman Hakim programmable valve n = 3, DP component of Miethke proGAV 2.0 valve n = 2) from eight hydrocephalic patients (four male), in whom valve malfunction was assumed between 2016 and 2017, were replaced with a new valve. Four patients suffered from idiopathic normal pressure (iNPH), three patients from malresorptive and one patient from obstructive hydrocephalus. Post-hoc analysis revealed a significant difference (p < 0.001) of the flow rate between each explanted valve and their corresponding reference valve, at each DP. In all patients, significant alterations of flow rates were demonstrated, verifying a valve malfunction, which could not be objectified by the diagnostic tools used in the clinical routine. In cases with obscure clinical VPS insufficiency, valve deficiency should be considered.

scholarly journals A modular microfluidic system based on a multilayered configuration to generate large-scale perfusable microvascular networks

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Tao Yue ◽  
Da Zhao ◽  
Duc T. T. Phan ◽  
Xiaolin Wang ◽  
Joshua Jonghyun Park ◽  
...  
Keyword(s):  
Large Scale ◽  
Circulatory System ◽  
Vertical Direction ◽  
Microfluidic System ◽  
Vital Role ◽  
Microvascular Networks ◽  
Biological Studies ◽  
Wide Range ◽  
High Flexibility

AbstractThe vascular network of the circulatory system plays a vital role in maintaining homeostasis in the human body. In this paper, a novel modular microfluidic system with a vertical two-layered configuration is developed to generate large-scale perfused microvascular networks in vitro. The two-layer polydimethylsiloxane (PDMS) configuration allows the tissue chambers and medium channels not only to be designed and fabricated independently but also to be aligned and bonded accordingly. This method can produce a modular microfluidic system that has high flexibility and scalability to design an integrated platform with multiple perfused vascularized tissues with high densities. The medium channel was designed with a rhombic shape and fabricated to be semiclosed to form a capillary burst valve in the vertical direction, serving as the interface between the medium channels and tissue chambers. Angiogenesis and anastomosis at the vertical interface were successfully achieved by using different combinations of tissue chambers and medium channels. Various large-scale microvascular networks were generated and quantified in terms of vessel length and density. Minimal leakage of the perfused 70-kDa FITC-dextran confirmed the lumenization of the microvascular networks and the formation of tight vertical interconnections between the microvascular networks and medium channels in different structural layers. This platform enables the culturing of interconnected, large-scale perfused vascularized tissue networks with high density and scalability for a wide range of multiorgan-on-a-chip applications, including basic biological studies and drug screening.

Experimental investigation of the influence of the hydraulic performance of an axial blood pump on intraventricular blood flow

2021 ◽  
pp. 039139882110130
Author(s):  
Guang-Mao Liu ◽  
Fu-Qing Jiang ◽  
Xiao-Han Yang ◽  
Run-Jie Wei ◽  
Sheng-Shou Hu
Keyword(s):  
Blood Flow ◽  
Particle Image ◽  
Swirling Flow ◽  
Blood Stasis ◽  
Systemic Circulation ◽  
Operating Conditions ◽  
Blood Pump ◽  
Image Velocimetry ◽  
Ct Data

Blood flow inside the left ventricle (LV) is a concern for blood pump use and contributes to ventricle suction and thromboembolic events. However, few studies have examined blood flow inside the LV after a blood pump was implanted. In this study, in vitro experiments were conducted to emulate the intraventricular blood flow, such as blood flow velocity, the distribution of streamlines, vorticity and the standard deviation of velocity inside the LV during axial blood pump support. A silicone LV reconstructed from computerized tomography (CT) data of a heart failure patient was incorporated into a mock circulatory loop (MCL) to simulate human systemic circulation. Then, the blood flow inside the ventricle was examined by particle image velocimetry (PIV) equipment. The results showed that the operating conditions of the axial blood pump influenced flow patterns within the LV and areas of potential blood stasis, and the intraventricular swirling flow was altered with blood pump support. The presence of vorticity in the LV from the thoracic aorta to the heart apex can provide thorough washing of the LV cavity. The gradually extending stasis region in the central LV with increasing blood pump support is necessary to reduce the thrombosis potential in the LV.

scholarly journals Using a roller pump for establishing extra-corporal membrane oxygenation (ECMO) – technical considerations for times of crisis

Perfusion ◽  
2021 ◽  
pp. 026765912199618
Author(s):  
Mirko Kaluza ◽  
Benjamin May ◽  
Torsten Doenst
Keyword(s):  
Flow Characteristics ◽  
Centrifugal Pumps ◽  
Roller Pump ◽  
Silicone Tubing ◽  
Heart Lung Machine ◽  
Surface Irregularities ◽  
Set Up ◽  
Flow Detection ◽  
Silicon Tubing

Objective: The COVID-19 pandemic requires thinking about alternatives to establish ECMO when often-limited hardware resources are exhausted. Heart-lung-machines may potentially be used for ECMO but contain roller pumps as compared to centrifugal pumps in ECMO-circuits. We here tested roller pumps as rescue pump for ECMO-establishment. Methods: We set up in vitro circuits on roller pumps from C5 heart-lung-machine with 5 l/minutes flow. In two series, we placed either PVC or silicon tubing for an ECMO circuit into the roller pump. We assessed the mechanical stress on the tubing (aiming to run the pump for at least 1 week), measured the temperature increase generated by the friction and assessed flow characteristics and its measurement in simulated situations resembling tube kinking and suction. Results: The roller pumps led to expected and unexpected adverse events. PVC tubing burst between 36 and 78 hours, while silicon tubing lasted for at least 7 days. At 7 days, the silicone tubing showed significant signs of roller pump wear visible on the outside. The inside, however, was free of surface irregularities. Using these tubings in a roller pump led to a remarkable increase in circuit temperature (PVC: +12.0°C, silicone +2.9°C). Kinking or suction on the device caused the expected dramatic flow reduction (as assessed by direct measurement) while the roller pump display continued to show the preset flow. The roller pump is therefore not able to reliably determine the true flow rate. Conclusion: Roller pumps with silicone tubing but not PVC tubing may be used for running ECMO circuits. Silicone tubing may endure the roller pump shear forces for up to 1 week. Thus, repeated tubing repositioning may be a solution. Circuit heating and substantial limitations in flow detection should increase attention if clinical use in situations of crisis is considered.

Modeling Endoleaks and Collateral Reperfusion following Endovascular AAA Exclusion

2003 ◽  
Vol 10 (3) ◽  
pp. 424-432 ◽  
Author(s):  
Chuh K. Chong ◽  
Thien V. How ◽  
Geoffrey L. Gilling-Smith ◽  
Peter L. Harris
Keyword(s):  
Stent Graft ◽  
Aortic Pressure ◽  
Type I ◽  
Type Ii ◽  
Pump System ◽  
Type Ii Endoleak ◽  
Type I Endoleak ◽  
The Impact ◽  
Mean Aortic Pressure

Purpose: To investigate the effect on intrasac pressure of stent-graft deployment within a life-size silicone rubber model of an abdominal aortic aneurysm (AAA) maintained under physiological conditions of pressure and flow. Methods: A commercial bifurcated device with the polyester fabric preclotted with gelatin was deployed in the AAA model. A pump system generated physiological flow. Mean and pulse aortic and intrasac pressures were measured simultaneously using pressure transducers. To simulate a type I endoleak, plastic tubing was placed between the aortic wall and the stent-graft at the proximal anchoring site. Type II endoleak was simulated by means of side branches with set inflow and outflow pressures and perfusion rates. Type IV endoleak was replicated by removal of gelatin from the graft fabric. Results: With no endoleak, the coated graft reduced the mean and pulse sac pressures to negligible values. When a type I endoleak was present, mean sac pressure reached a value similar to mean aortic pressure. When net flow through the sac due to a type II endoleak was present, mean sac pressure was a function of the inlet pressure, while pulse pressure in the sac was dependent on both inlet and outlet pressures. As perfusion rates increased, both mean and pulse sac pressures decreased. When there was no outflow, mean sac pressure was similar to mean aortic pressure. In the presence of both type I and type II endoleaks, mean sac pressure reached mean aortic pressure when the net perfusion rate was low. Conclusions: In vitro studies are useful in gaining an understanding of the impact of different types of endoleaks, in isolation and in combination, on intrasac pressure after aortic stent-graft deployment.

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