Filmes Finos de Alumina em substratos de alumínio 5052 por processo de Oxidação Eletrolítica à Plasma

Alumina, or aluminum oxide, has several applications as Biomaterial in addition to being used in machining tools, grinding, thermal insulation, shielding, refractory for heating furnaces, electrical insulators, electronic components due to its high resistance to high temperatures, hardness, mechanical resistance and chemical resistance. Its achievement is due to intermediate processes in the manufacture of primary aluminum, as well as physical and chemical deposition processes. This work aims to obtain thin films of alumina through the Plasma Electrolytic Oxidation process, using the 5052 aluminum alloy as a substrate. This study serves as a basis for applications of thin films of alumina in Implantable Centrifugal Blood Pump rotors used as Ventricular Assist Devices developed by the Laboratory of Bioengineering and Biomaterials in the Federal Institute of São Paulo. The samples were prepared with same surface area of the rotor, in order to simulate the same behavior of the rotor film deposition, thus being able to observe the morphology at different oxidation times and energies, and how the influence of time and energy on the generation of plasma micro-arcs act in the formation of the alumina film. The film was characterized with Scanning Electron Microscopy, Dispersive Energy Spectroscopy and X-Ray Diffraction. The ceramic films in the PEO are created by the reaction of the electrolytic solution with the electrical discharges produced by a source, being deposited on the surface of the samples through micro arcs. In the future, the films will be tested for cell viability, and will also be evaluated as an internal coating of Implantable Centrifugal Blood Pump for use as Ventricular Assist Device.

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Centrifugal Blood Pump for Temporary Ventricular Assist Devices With Low Priming and Ceramic Bearings

Artificial Organs ◽

10.1111/aor.12231 ◽

2013 ◽

Vol 37 (11) ◽

pp. 942-945 ◽

Cited By ~ 2

Author(s):

Juliana Leme ◽

Cibele da Silva ◽

Jeison Fonseca ◽

Bruno Utiyama da Silva ◽

Beatriz Uebelhart ◽

...

Keyword(s):

Ventricular Assist Devices ◽

Blood Pump ◽

Ventricular Assist ◽

Centrifugal Blood Pump ◽

Assist Devices

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Effects of gravity on flow rate estimations of a centrifugal blood pump using the eccentric position of a levitated impeller

The International Journal of Artificial Organs ◽

10.1177/0391398820917149 ◽

2020 ◽

Vol 43 (12) ◽

pp. 774-781

Author(s):

Shuya Shida ◽

Toru Masuzawa ◽

Masahiro Osa

Keyword(s):

Flow Rate ◽

Ventricular Assist Devices ◽

Blood Pump ◽

Accurate Estimation ◽

Ventricular Assist ◽

Centrifugal Blood Pump ◽

Assist Devices ◽

Flow Estimation ◽

Magnetically Levitated ◽

Gravity Direction

Implantable ventricular assist devices are a type of mechanical circulatory support for assisting the pumping of the heart. Accurate estimation of the flow rate through such devices is critical to ensure effective performance. A novel method for estimating the flow rate using the passively stabilized position of a magnetically levitated impeller was developed by our group. However, the performance of the method is affected by the gravity vector, which depends on the patient’s posture. In this study, the effects of gravity on the flow estimation method are analyzed, and a compensation method is proposed. The magnetically levitated impeller is axially suspended and radially restricted by passive stability in a centrifugal blood pump developed by our group. The gravity effects were evaluated by analyzing the relationships between the radial position of the magnetically levitated impeller and the flow rate with respect to the gravity direction. Accurate estimation of the flow rate could not be achieved when the direction of gravity with respect to impeller was unknown. A mean absolute error of up to 4.89 L/min was obtained for flow rate measurement range of 0–5 L/min. However, analysis of the equilibrium of forces on the passively stabilized impeller indicated that the effects of gravity on the flow estimation could be compensated by performing additional measurements of the gravity direction with respect to impeller. The method for compensating the effects of gravity on the flow estimation should improve the performance of therapy with the implantable ventricular assist devices.

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The CentriMag Centrifugal Blood Pump as a Benchmark for In Vitro Testing of Hemocompatibility in Implantable Ventricular Assist Devices

Artificial Organs ◽

10.1111/aor.12351 ◽

2014 ◽

Vol 39 (2) ◽

pp. 93-101 ◽

Cited By ~ 36

Author(s):

Chris H.H. Chan ◽

Ina Laura Pieper ◽

Rebecca Hambly ◽

Gemma Radley ◽

Alyssa Jones ◽

...

Keyword(s):

Ventricular Assist Devices ◽

Blood Pump ◽

In Vitro Testing ◽

Ventricular Assist ◽

Centrifugal Blood Pump ◽

Assist Devices

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Dynamic Model and Analysis of a Centrifugal Blood Pump and Induction Motor

10.1115/imece2001/bed-23133 ◽

2001 ◽

Author(s):

P. Ruby Mawasha ◽

Omotoye Omotoso ◽

Paul Lam ◽

Ted Conway

Keyword(s):

Induction Motor ◽

Dynamic Model ◽

Characteristic Curve ◽

Volumetric Flow Rate ◽

Ventricular Assist Devices ◽

Blood Pump ◽

Ventricular Assist ◽

Centrifugal Blood Pump ◽

Blood Pumps ◽

The Mathematical Model

Abstract A dynamic model of a centrifugal blood pump, induction motor, and channel is investigated through nonlinear analysis. A centrifugal blood pump with forward curved blades and an induction motor is subject to constant inlet and outlet mass flow conditions leading to a channel. The steady state pressure drop versus volumetric flow rate relation is described by a constitutive model containing a cubic nonlinearity obtained from centrifugal pump characteristic curves. Within certain operating regimes along the characteristic curve, the model exhibits self-excited pulsatile periodic morion and the qualitative features of the response can be understood in terms of the underlying model. Further, the mathematical model is a more general model and can be used by the designer of centrifugal blood pumps and other ventricular assist devices (VADs) to determine the instability mechanisms.

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Temporary Mechanical Circulatory Support: A Review of the Options, Indications, and Outcomes

Clinical Medicine Insights Cardiology ◽

10.4137/cmc.s15718 ◽

2014 ◽

Vol 8s1 ◽

pp. CMC.S15718 ◽

Cited By ~ 10

Author(s):

Nisha A. Gilotra ◽

Gerin R. Stevens

Keyword(s):

Extracorporeal Membrane Oxygenation ◽

Mechanical Circulatory Support ◽

Clinical Applications ◽

Ventricular Assist Devices ◽

Blood Pump ◽

Circulatory Support ◽

Disease Entity ◽

Significant Morbidity ◽

Ventricular Assist ◽

Acute Setting

Cardiogenic shock remains a challenging disease entity and is associated with significant morbidity and mortality. Temporary mechanical circulatory support (MCS) can be implemented in an acute setting to stabilize acutely ill patients with cardiomyopathy in a variety of clinical situations. Currently, several options exist for temporary MCS. We review the indications, contraindications, clinical applications, and evidences for a variety of temporary circulatory support options, including the intra-aortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), CentriMag blood pump, and percutaneous ventricular assist devices (pVADs), specifically the TandemHeart and Impella.

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Impact of Washout Blades in a Multiple Disk Centrifugal Blood Pump

10.1115/imece1999-0377 ◽

1999 ◽

Author(s):

Michelle J. Holmes ◽

Gerald E. Miller

Keyword(s):

Blood Flow ◽

Flow Patterns ◽

Blood Pump ◽

Ventricular Assist ◽

Centrifugal Blood Pump ◽

Bridge To Transplant ◽

Rotation Rates ◽

Parallel Configuration ◽

Output Characteristics ◽

Blood Flow Patterns

Abstract A multiple disk, centrifugal blood pump (MDCP) for use as a ventricular assist device or as a bridge to transplant device has previously been designed and its output characteristics have been analyzed (Miller et al. 1990, 1993). The propelling mechanism of this device consists of six multiple disks assembled in a parallel configuration. Upon rotation these disks create centrifugal and shearing forces, which work to propel the fluid. This pump operates at lower rotation rates than other rotary blood pumps. The lower rotation rates reduce the chance for hemolysis, but may promote thrombosis formation due to stagnant blood flow. Previous flow visualization studies conducted by Miller et al. (1995) analyzed the blood flow patterns within the device. Results of this study indicated a region of flow stagnation between the last solid disk and the housing. In this investigation, further studies were performed that verified this recirculation. To provide washout of this region, eight, small Lexan blades were attached to the back of the last disk. Reevaluation of the flow patterns, following the blade attachment, revealed that the addition of the blades was successful in producing washout, thus reducing the possibility of thrombosis formation.

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