scholarly journals In Vivo Testing of a Magnetically Suspended Centrifugal Pump Designed for Long-Term Use

1997 ◽  
Vol 20 (10) ◽  
pp. 562-569 ◽  
Author(s):  
T. Yamada ◽  
K. Nishimura ◽  
T. Akamatsu ◽  
T. Tsukiya ◽  
C.H. Park ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Rotational Speed ◽  
Thrombus Formation ◽  
Current Mode ◽  
Left Ventricular ◽  
Centrifugal Pumps ◽  
Motor Current ◽  
Magnetically Suspended Centrifugal Pump

The life of currently-available centrifugal pumps is limited to no more than three days. As a magnetically suspended centrifugal pump (MSCP) contains no shaft or seal, it could be expected to have a longer life expectancy. The MSCP was evaluated in a chronic animal model using eight adult sheep. Left ventricular assist with the MSCP was instituted between the left atrium and the descending aorta. The flow rates ranged from 2.5 to 6.0 L/min. The duration of the experiments ranged from 14 to 60 days. No mechanical failure occurred. The plasma free hemoglobin levels remained within an acceptable range (3-19 mg/dL). No reduction in the counts of red blood cells or platelets was observed. Thrombus formation within the MSCP was recognized in one pump. The main reason for termination was thromboembolism derived from the circuits. Three types of regulation methods (constant rotational speed, constant motor current, and controlled motor current) were also investigated. Regulation by a constant motor current mode altered the pressure-flow (P-Q) characteristics, and thereby, a steadier pump flow was obtained compared with regulation in the constant rotational speed mode. Moreover, the controlled motor current mode can change the P-Q relationship. These results demonstrate that the MSCP is a promising device for long-term use.

Long-Term In Vivo Left Ventricular Assist Device Study With a Titanium Centrifugal Pump

ASAIO Journal ◽  
1998 ◽  
Vol 44 (5) ◽  
pp. M619-M623 ◽  
Author(s):  
Goro Ohtsuka ◽  
Kin-ichi Nakata ◽  
Masaharu Yoshikawa ◽  
Juergen Mueller ◽  
Tamaki Takano ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Left Ventricular Assist Device ◽  
Ventricular Assist Device ◽  
Left Ventricular ◽  
Assist Device ◽  
Ventricular Assist ◽  
Left Ventricular Assist

scholarly journals Oral delivery of xenon for cardiovascular protection

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xing Yin ◽  
Melanie R. Moody ◽  
Valeria Hebert ◽  
Melvin E. Klegerman ◽  
Yong-Jian Geng ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Oral Delivery ◽  
Noble Gas ◽  
Left Ventricular ◽  
Beneficial Effects ◽  
Normal Left Ventricular ◽  
Term Administration ◽  
Apoe Knockout Mice

Abstract Cardiac hypertrophy often causes impairment of cardiac function. Xenon (Xe), a naturally occurring noble gas, is known to provide neurological and myocardial protection without side effects. The conventional method of Xe delivery by inhalation is not feasible on a chronic basis. We have developed an orally deliverable, effective Xe formulation for long-term administration. We employed 2-hydroxypropyl)-β-cyclodextrin (HPCD), which was dissolved in water to increase the Xe concentration in solution. The beneficial effects of long-term oral administration of Xe-enriched solutions on cardiovascular function were evaluated in vivo. HPCD increased Xe solubility from 0.22 mM to 0.67 mM (3.8-fold). Aged ApoE knockout mice fed high-fat diet for 6 weeks developed hypertension, and myocardial hypertrophy with impaired cardiac function. Oral Xe prevented this ischemic damage, preserving normal blood pressure, while maintaining normal left ventricular mass and wall thickness. This novel formulation allows for gastrointestinal delivery and cardiovascular stabilization.

Treatment of Cerebral Aneurysms With Flow Divertors: Long Term Results in an In Vivo Model

2007 ◽  
Author(s):  
Chander Sadasivan ◽  
Baruch B. Lieber ◽  
Liliana Cesar ◽  
Jaehoon Seong ◽  
Ajay K. Wakhloo
Keyword(s):  
Thrombus Formation ◽  
Cerebral Aneurysms ◽  
Long Term Results ◽  
In Vivo Model ◽  
Parent Artery ◽  
Momentum Exchange ◽  
Aneurysm Neck ◽  
Flow Stasis

Subarachnoid hemorrhagic stroke is a devastating illness with a 30-day mortality rate of 45% and is mostly caused due to the rupture of an intracranial aneurysm. Although these aneurysms are currently treated surgically by clipping, or, endovascularly by coiling and stent-assisted coiling, the feasibility of successfully treating aneurysms solely by the placement of an intravascular flow-diverting mesh across the aneurysm neck was established more than a decade ago [1]. Flow divertors disrupt the momentum exchange between the parent artery and aneurysm and significantly reduce intraaneurysmal hydrodynamic vorticity. The resultant flow stasis promotes thrombus formation within the aneurysm sac, which eventually matures into fibrotic tissue, leading to the exclusion of the aneurysm from the circulation. With the increased use of stents in the intracranial circulation, cases where coiling is not feasible, or is staged as a secondary procedure, are providing clinical evidence of the successful treatment of aneurysms with stents alone [2,3]. Such reports are sporadic and, moreover, the devices used are not designed to be flow divertors. Methodological evidence of the performance of appropriately designed flow divertors in treating cerebral aneurysms is currently unavailable.

scholarly journals Development of Active Centrifugal Pump for Microfluidic CD Platforms

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 140
Author(s):  
Ala’aldeen Al-Halhouli ◽  
Baha El Far ◽  
Ahmed Albagdady ◽  
Wisam Al-Faqheri
Keyword(s):  
Centrifugal Pump ◽  
Rotational Speed ◽  
Real Life ◽  
Chemical Processes ◽  
Performance Tests ◽  
Centrifugal Pumps ◽  
Biological Assays ◽  
Unidirectional Flow ◽  
Pumping Efficiency ◽  
Potential Applications

The continuous emerging of microfluidic compact disc (CD) platforms for various real-life applications motivates researchers to explore new innovative ideas towards more integrated active functions. However, microfluidic CDs have some drawbacks, including the unidirectional flow that limits the usable space for multi-stepped biological and chemical assays. In this work, a novel active and bidirectional centrifugal pump is developed and integrated on microfluidic CDs. The design of the developed pump partially replicates the designs of the conventional centrifugal pumps with a modification in the connecting channels’ positions that allow the developed pump to be reversible. The main advantage of the proposed centrifugal pump is that the pumping speed can be accurately controlled during spinning or while the microfluidic CD is stationary. Performance tests show that the pumping speed can reach up to 164.93 mm3/s at a pump rotational speed (impellers speed) of 4288 rpm. At that speed, 1 mL of water could be pumped in 6.06 s. To present a few of the potential applications of the centrifugal pump, flow reciprocation, bidirectional pumping, and flow switching were performed and evaluated. Results show that the developed centrifugal pump can pump 1096 µL of liquid towards the CD center at 87% pumping efficiency while spinning the microfluidic CD at 250 rpm. This novel centrifugal pump can significantly widen the range of the applicability of microfluidic CDs in advanced chemical processes and biological assays.

A New Magnetically Suspended Centrifugal Pump: In Vitro and Preliminary In Vivo Assessment

2008 ◽  
Vol 20 (2) ◽  
pp. 128-131 ◽  
Author(s):  
Chang-Hee Park ◽  
Kazunobu Nishimura ◽  
Teruaki Akamatsu ◽  
Tomonori Tsukiya ◽  
Katsuhiko Matsuda ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
In Vivo Assessment ◽  
Magnetically Suspended Centrifugal Pump

Haemolysis during cardiopulmonary bypass: an in vivo comparison of standard roller pumps, nonocclusive roller pumps and centrifugal pumps

Perfusion ◽  
1999 ◽  
Vol 14 (1) ◽  
pp. 3-10 ◽  
Author(s):  
S D Hansbro ◽  
D AC Sharpe ◽  
R Catchpole ◽  
K R Welsh ◽  
C M Munsch ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Centrifugal Pump ◽  
Centrifugal Pumps ◽  
Coronary Artery Surgery ◽  
Roller Pump ◽  
Cardiotomy Suction ◽  
Principal Source ◽  
Free Haemoglobin ◽  
Blood Elements

Cardiopulmonary bypass (CPB) involves the use of either an occlusive roller pump or centrifugal pump. Damage to blood elements, including haemolysis, may arise from occlusion when using a roller pump; the appropriate degree of occlusion has not yet been determined scientifically. Centrifugal and nonocclusive roller pumps are reputed to reduce haemolysis. The objective of this study was to compare haemolysis caused by a standard roller pump with a dynamically set nonocclusive roller pump and with a centrifugal pump. We prospectively randomized 60 patients undergoing routine coronary artery surgery into three groups: standard roller pump (STD, n = 20), dynamically set roller pump (DYN, n = 20), or centrifugal pump (CEN, n = 20). The level of plasma free haemoglobin (FHb) was measured preoperatively, and the rate of formation of FHb (in mg/dl/min) was determined at the end of the ischaemic phase and at the end of CPB. Cardiotomy suction blood was isolated for the ischaemic phase and returned before the end of CPB. It was found that there were no differences between the groups in demographic or operative variables. The rate of formation of FHb at the end of the ischaemic phase was similar for all groups (STD 0.108 ± 0.10, DYN 0.117 ± 0.08, CEN 0.129 ± 0.07). At the end of CPB, after return of the cardiotomy suction blood, there was a significant (<0.001) increase in the rate of formation of FHb in all groups. The increase was similar for each of the groups (STD 0.424 ± 0.17, DYN 0.481 ± 0.20, CEN 0.471 ± 0.18). We conclude that the rates of haemolysis are similar for each of the pump types, and no benefit is conferred by the use of either a dynamically set roller pump or a centrifugal pump compared with the standard roller pump. The return of the cardiotomy suction blood to the circulation is the principal source of plasma free haemoglobin.

The Rotating Cavitation Performance of a Centrifugal Pump with a Splitter-Bladed Inducer under Different Rotational Speed

2015 ◽  
Vol 32 (3) ◽  
Author(s):  
XiaoMei Guo ◽  
ZuChao Zhu ◽  
BaoLing Cui ◽  
Yi Li
Keyword(s):  
Centrifugal Pump ◽  
Rotational Speed ◽  
High Speed ◽  
Internal Flow ◽  
Centrifugal Pumps ◽  
Cavitation Flow ◽  
Operation Condition ◽  
Cavitation Performance ◽  
Cavitation Behavior ◽  
Suction Performance

AbstractDesigning inducer is one of the effective ways to improve the suction performance of high-speed centrifugal pumps. The operation condition including rotational speeds can affect the internal flow and external performance of high-speed centrifugal pumps with an inducer. In order to clarify the rotating cavitation performance of a centrifugal pump with a splitter-bladed inducer under different rotational speed, a centrifugal pump with a splitter-bladed inducer is investigated in the work. By using Rayleigh–Plesset equations and Mixture model, the cavitation flow of centrifugal pump is numerically simulated, as well as the external performance experimental test is carried out. It is found that the cavitation area increases with the rotational speeds. The location of the passage where cavitation is easy to appear is explored. Asymmetric cavitation behavior is observed. That, the trail of the inducer is easy to take cavitation when the rotational speed is increased to a degree, is also observed. The trend of

Development of a Magnetically Suspended Centrifugal Pump as a Cardiac Assist Device for Long-Term Application

ASAIO Journal ◽  
1996 ◽  
Vol 42 (1) ◽  
pp. 68-71 ◽  
Author(s):  
Kazunobu Nishimura ◽  
Chang-Hee Park ◽  
Teruaki Akamatsu ◽  
Tomoyuki Yamada ◽  
Toshihiko Ban
Keyword(s):  
Centrifugal Pump ◽  
Assist Device ◽  
Cardiac Assist ◽  
Cardiac Assist Device ◽  
Magnetically Suspended Centrifugal Pump

Polydopamine nanoparticles' activity and long-term stability should be fully studied for gene therapy applications

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Structural Control ◽  
Thrombus Formation ◽  
Contact Process ◽  
Protein Corona ◽  
Structure Property ◽  
Term Stability ◽  
Long Term Stability

Many substantial hurdles must be solved for in vivo or in vitro clinical translation of the Polydopamine (PDA)-based nanomaterials. Excessive accumulation of residual unreacted DA and specific metabolites (DA or other small molecules) of PDA in vivo may trigger a possible syndrome of dopamine dysregulation characterized by addictive behaviour, as DA may act as an endogenous neurotoxin when its vesicular sequestration is dysregulated. PDA nanoparticles' activity and long-term stability should be fully studied for in vivo applications aside from probable toxicity. According to the findings, PDA's strong reactivity with numerous functional groups (catechol, quinone, and amine) is comparatively favorable, but in mild circumstances it may have negative effects on the organism owing to direct alcohol interactions. More crucially, the charged, moist adhesive PDA has a high affinity for protein attachment, which might be a major defect in the blood contact process. Direct blood contact with these PDA-based nanomaterials with high specific surface area would result in fast protein adsorption, the establishment of a "protein corona" within minutes, and increased thrombus formation risk. In vitro applications, on the other hand, can prevent the threat of detrimental cell or tissue effects. New rules, theories and processes on structure property performance relationships may be developed by researching the in vivo bioapplications of the above-mentioned PDA nanoarchitectures, possibly leading to fundamental and useful insights into in-vitro material translations. Despite the fact that major impediments to structural control persist, it is predicted that in the future, electron coupling will bring new answers to challenges of improved illness diagnosis and therapy.

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