Special Technical Problems in Rotary Heart Pumps

2011 ◽  
Vol 140 ◽  
pp. 220-228
Author(s):  
Kun Xi Qian
Keyword(s):  
Energy Supply ◽  
Artificial Heart ◽  
Thrombus Formation ◽  
Automatic Measurement ◽  
Technical Problems ◽  
Inductive System

R&D of artificial heart has lasted over 50 years, now both rotary and diaphragm pumps can assist the circulation of the patients several years, after solving many technical problems. In rotary heart pumps, the basic technical problems have been the implantability, the compatibility, the pulsatility, the durability, the biventricular assist, the automatic measurement, the bionic control and the thrombus formation. This paper summarizes the author’s contributions in solving these problems and shares the novelties of some Chinese rotary heart pumps with the readers. The energy supply is one of the most important unsolved problems in rotary heart pumps; the present methods either by use of electric wire cross the skin or using transcutaneous inductive system are problematic because they are neither convenient nor reliable.

Calcification and Thrombus Formation on Polymer Surfaces of an Artificial Heart

1998 ◽  
pp. 110-117 ◽  
Author(s):  
Kou Imachi ◽  
Yusuke Abe ◽  
Tsuneo Chinzei ◽  
Kunihiko Mabuchi ◽  
Kazunori Baba ◽  
...  
Keyword(s):  
Artificial Heart ◽  
Thrombus Formation ◽  
Polymer Surfaces

scholarly journals Sustainability Challenges of The Landfill Gas Power Plants in Indonesia

2021 ◽  
Vol 940 (1) ◽  
pp. 012028
Author(s):  
R Budiarto ◽  
M Gozan ◽  
D Novitasari ◽  
N S Wahyuni ◽  
D Y N Naimah
Keyword(s):  
Energy Supply ◽  
Power Plants ◽  
Local Community ◽  
Landfill Gas ◽  
Maintenance Phase ◽  
Technical Problems ◽  
Social Challenges ◽  
Performance Targets ◽  
Funding Mechanism ◽  
Sustainability Challenges

Abstract As part of urbanization, waste causes a significant challenge in Indonesia. As part of the solution to this challenge is applying the landfill gas (LFG) powerplant. Various efforts are being conducted to implement the LFG powerplant in Indonesia. The literature review was conducted to focusing on the performance sustainability of the LFG powerplant. The explaining power capacity, expected energy supply, actual energy supply, problems, and their cause and impact data are presented. All LFG power plants show technical problems, such as leakage gas pipe, defected gas capture, absence of gas storage and purification equipment, and limited monitoring system. Financial and social challenges exacerbate the technical issues that risk the system’s sustainability, such as unclear funding mechanism, lack of capacity from stakeholders, and conflict with the local community. All of the issues hindered achieving performance targets in the powerplant development, operation, and maintenance phase.

Medical-Grade Polyurethanes: Their Crucial Role in Artificial Hearts

1987 ◽  
Vol 110 ◽  
Author(s):  
Michael Szycher
Keyword(s):  
Crucial Role ◽  
Artificial Heart ◽  
Thrombus Formation ◽  
The Body ◽  
Foreign Objects ◽  
Artificial Hearts ◽  
Medical Grade

One of the most crucial requirements since the inception of the artificial heart program has been the need to develop biomaterials specific to chronic implantation. Major problems include the propensity for thrombus formation at the blood-materials interface, long-term flexing reliability, and the tendency of the body to reject foreign objects.

Conditioning Surfaces to Suit the Biomedical Environment: Recent Progress

1982 ◽  
Vol 104 (4) ◽  
pp. 257-271 ◽  
Author(s):  
R. E. Baier
Keyword(s):  
Artificial Heart ◽  
Thrombus Formation ◽  
Test Methods ◽  
Relative Strength ◽  
Cardiovascular Devices ◽  
Prosthetic Devices ◽  
Dental Prostheses ◽  
Oral Environment ◽  
Effective Function ◽  
Strength Of Adhesion

One major determinant of the suitability of various engineering materials for use in biological settings is the relative strength of adhesion obtained between those materials and their contacting viable phases. Maximal adhesive strength and immobility are desired for orthopedic and dental implants, for example, while minimal bioadhesion is critical to preventing unwanted thrombus formation in cardiovascular devices, plaque buildup on dental prostheses, and bacterial fouling of heat exchangers. This article reviews the principles of adhesive phenomena in such harsh environments, introduces some novel test methods and materials available for sensitive analysis of the earliest interfacial events, and provides a brief illustration of their use in the study of surface fouling of food processing equipment. Attention is then directed to adhesive phenomena in the oral environment, examining new surface conditioning methods for the prevention of micro-organism deposits, as well as the promotion of excellent tissue bonding to implanted prosthetic devices. Other bioadhesive phenomena considered include those important to the safe and effective function of new cardiovascular devices, such as the artificial heart and substitute blood vessels, and the prevention of biological fouling of materials in the sea. Comparisons of the primary interfacial events in these diverse systems—all wet, salty, and biochemically active—illustrate that Nature has been very conservative in accommodating encounters with strange boundaries. As with a classic drama, the players and timing may vary, but the script remains the same.

Measurement of Thromboembolism: Application to Patients with a Jarvik Total Artificial Heart

1987 ◽  
Vol 110 ◽  
Author(s):  
George A. Adams ◽  
Brian Labow ◽  
Ian Carmody ◽  
Christiane Hallee ◽  
Wilbert J. Keon
Keyword(s):  
Artificial Heart ◽  
Thrombus Formation ◽  
Total Artificial Heart ◽  
Circulatory Support ◽  
Cardiovascular Devices ◽  
Arterial Circulation ◽  
Arterial Blood ◽  
Coated Surfaces

AbstractThere have been in excess of 90 implantations of several different types of artificial heart (TAH) into patients. The bulk of these implantations have been using the Jarvik TAH as a bridge to provide interim circulatory support for the failed heart while a donor heart is being located and transported. Attempt to use the Jarvik TAH as a permanent, long-term heart substitute were complicated by hemorrhaging, sepsis, peripheral-organ failure and strokes [1]. These latter sequelae are thought to be due to thromboembolism and this concept is supported by the examination of explanted TAH from Barney Clark, the first recipient of the Jarvik TAH, which revealed large thrombus formation around the valve seats and microthrombi on the diaphragm that may have been the sites of thromboemboli [2]. In the case of bridges, the implantation periods are shorter, averaging 10 to 14 days but still a significant number of these patients have had thromboembolic events and explanted TAH have had microscopic aggregations of platelets and thrombi [3,4]. The response of blood to the constituent biomaterials of all cardiovascular devices is highly variable [5]. The documentation of thrombus on a biomaterial surface does not prove it will detach nor does the lack of thrombus on a surface indicate that the surface is benign, as thrombus could have formed and embolized. We have used two approaches to study the dynamic process of thrombogenesis and thromboembolism, in vivo and in vitro. Whole arterial blood samples were analyzed for thromboemboli as an in vivo assessment and epifluorescent videomicroscopy was used to monitor the mechanism of thrombosis, in vitro. Microparticles were found in the arterial circulation of patients with a Jarvik TAB and platelet thrombi were observed to form and embolize from Biomer-coated surfaces during perfusion.

Thrombus formation and the disintegration of the superficial layer of implanted artificial heart valves

1976 ◽  
Vol 10 (4) ◽  
pp. 220-222
Author(s):  
R. P. Zubarev ◽  
E. V. Kolpakov ◽  
G. V. Morov ◽  
R. Ya. Gabeskiriya
Keyword(s):  
Artificial Heart ◽  
Heart Valves ◽  
Thrombus Formation ◽  
Superficial Layer ◽  
Artificial Heart Valves

Fondaparinux and enoxaparin in comparison to unfractionated heparin in preventing thrombus formation on mechanical heart valves in an ex vivo rabbit model

2003 ◽  
Vol 90 (08) ◽  
pp. 245-251 ◽  
Author(s):  
Michael Buerke ◽  
Baerbel Hauroeder ◽  
Dirk Peetz ◽  
Ferdinand Hundt ◽  
Christoph Bickel ◽  
...  
Keyword(s):  
Unfractionated Heparin ◽  
Heart Valve ◽  
Artificial Heart ◽  
Heart Valves ◽  
Thrombus Formation ◽  
Rabbit Model ◽  
Flow Chamber ◽  
Group Iv ◽  
Group Iii ◽  
Group I

SummaryThe aim of the present study was to investigate the efficacy of three different parenterally administered anticoagulants for the prevention of thrombus formation on artificial heart valves in an experimental rabbit model.Unfractionated heparin was administered intravenously in group I (n = 10), Enoxaparin subcutaneously in group II (n = 10), fondaparinux intravenously in group III (n = 10), and no medication was administered to group IV (n = 9). Leaflets from Sulzer Carbomedics bileaflet mechanical heart valves were placed in a flow chamber. The flow chamber was filled with blood in a continuous circulation between the carotid artery and the jugular vein.In group IV the flow chamber was clotted after a median of 15 minutes of circulation. Weight analysis before and after 1 h of perfusion showed that the median thrombus weight was 18.0 mg in group I, 17.7 mg in group II, 20.3 mg in group III, and 30.8 mg in group IV. Further analysis by electron microscopy showed similar results regarding deposition of fibrin, platelets, and erythrocytes on leaflet surfaces.Fondaparinux and subcutaneously administered enoxaparin were as effective as intravenously administered unfractionated heparin in preventing thrombus formation on artificial heart valve leaflets in our investigation. This rabbit model, in which the heart valve leaflets were exposed to rabbit blood for a short time under laminar flow, should be further evaluated with respect to whether it can provide information about anti-thrombotic regimens in patients after mechanical heart valve replacement.

Redox Reactions in Lipid Membranes as a Model for Primordial Energy-Conserving Systems

1997 ◽  
Vol 161 ◽  
pp. 437-442
Author(s):  
Salvatore Di Bernardo ◽  
Romana Fato ◽  
Giorgio Lenaz
Keyword(s):  
Experimental Evidence ◽  
Lipid Membranes ◽  
Energy Supply ◽  
Redox Reactions ◽  
Living Systems ◽  
Asymmetric Distribution ◽  
Conservation Of Energy ◽  
Asymmetrical Distribution ◽  
Energy Conserving ◽  
Living Organisms

AbstractOne of the peculiar aspects of living systems is the production and conservation of energy. This aspect is provided by specialized organelles, such as the mitochondria and chloroplasts, in developed living organisms. In primordial systems lacking specialized enzymatic complexes the energy supply was probably bound to the generation and maintenance of an asymmetric distribution of charged molecules in compartmentalized systems. On the basis of experimental evidence, we suggest that lipophilic quinones were involved in the generation of this asymmetrical distribution of charges through vectorial redox reactions across lipid membranes.

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