Specification of Supervisory Control Systems for Ventricular Assist Devices

One of the most important recent improvements in cardiology is the use of ventricular assist devices (VADs) to help patients with severe heart diseases, especially when they are indicated to heart transplantation. The Institute Dante Pazzanese of Cardiology has been developing an implantable centrifugal blood pump that will be able to help a sick human heart to keep blood flow and pressure at physiological levels. This device will be used as a totally or partially implantable VAD. Therefore, an improvement on device performance is important for the betterment of the level of interaction with patient`s behavior or conditions. But some failures may occur if the device`s pumping control does not follow the changes in patient`s behavior or conditions. The VAD control system must consider tolerance to faults and have a dynamic adaptation according to patient`s cardiovascular system changes, and also must attend to changes in patient conditions, behavior, or comportments. This work proposes an application of the mechatronic approach to this class of devices based on advanced techniques for control, instrumentation, and automation to define a method for developing a hierarchical supervisory control system that is able to perform VAD control dynamically, automatically, and securely. For this methodology, we used concepts based on Bayesian network for patients` diagnoses, Petri nets to generate a VAD control algorithm, and Safety Instrumented Systems to ensure VAD system security. Applying these concepts, a VAD control system is being built for method effectiveness confirmation.

Mock circulatory system for the evaluation of left ventricular assist devices, endoluminal prostheses, and vascular diseases

A new digital computer mock circulatory system has been developed in order to replicate the physiologic and pathophysiologic characteristics of the human cardiovascular system. The computer performs the acquisition of pressure, flow, and temperature in an open loop system. A computer program has been developed in Labview programing environment to evaluate all these physical parameters. The acquisition system was composed of pressure, flow, and temperature sensors and also signal conditioning modules. In this study, some results of flow, cardiac frequencies, pressures, and temperature were evaluated according to physiologic ventricular states. The results were compared with literature data. In further works, performance investigations will be conducted on a ventricular assist device and endoprosthesis. Also, this device should allow for evaluation of several kinds of vascular diseases.

Single Axis Controlled Hybrid Magnetic Bearing for Left Ventricular Assist Device: Hybrid Core and Closed Magnetic Circuit

In previous studies, we presented main strategies for suspending the rotor of a mixed-flow type (centrifugal and axial) ventricular assist device (VAD), originally presented by the Institute Dante Pazzanese of Cardiology (IDPC), Brazil. Magnetic suspension is achieved by the use of a magnetic bearing architecture in which the active control is executed in only one degree of freedom, in the axial direction of the rotor. Remaining degrees of freedom, excepting the rotation, are restricted only by the attraction force between pairs of permanent magnets. This study is part of a joint project in development by IDPC and Escola Politecnica of Sao Paulo University, Brazil. This article shows advances in that project, presenting two promising solutions for magnetic bearings. One solution uses hybrid cores as electromagnetic actuators, that is, cores that combine iron and permanent magnets. The other solution uses actuators, also of hybrid type, but with the magnetic circuit closed by an iron core. After preliminary analysis, a pump prototype has been developed for each solution and has been tested. For each prototype, a brushless DC motor has been developed as the rotor driver. Each solution was evaluated by in vitro experiments and guidelines are extracted for future improvements. Tests have shown good results and demonstrated that one solution is not isolated from the other. One complements the other for the development of a single-axis-controlled, hybrid-type magnetic bearing for a mixed-flow type VAD.

Magnetic suspension of the rotor of a ventricular assist device of mixed flow type

This work presents results of preliminary studies concerning application of magnetic bearing in a ventricular assist device (VAD) being developed by Dante Pazzanese Institute of Cardiology-IDPC (Sao Paulo, Brazil). The VAD-IDPC has a novel architecture that distinguishes from other known VADs. In this, the rotor has a conical geometry with spiral impellers, showing characteristics that are intermediate between a centrifugal VAD and an axial VAD. The effectiveness of this new type of blood pumping principle was showed by tests and by using it in heart surgery for external blood circulation. However, the developed VAD uses a combination of ball bearings and mechanical seals, limiting the life for some 10 h, making impossible its long-term use or its use as an implantable VAD. As a part of development of an implantable VAD, this work aims at the replacement of ball bearings by a magnetic bearing. The most important magnetic bearing principles are studied and the magnetic bearing developed by Escola Politecnica of Sao Paulo University (EPUSP-MB) is elected because of its very simple architecture. Besides presenting the principle of the EPUSP-MB, this work presents one possible alternative for applying the EPUSP-MB in the IDPC-VAD.

A new approach to heart valve tissue engineering: mimicking the heart ventricle with a ventricular assist device in a novel bioreactor

The `biomimetic` approach to tissue engineering usually involves the use of a bioreactor mimicking physiological parameters whilst supplying nutrients to the developing tissue. Here we present a new heart valve bioreactor, having as its centrepiece a ventricular assist device (VAD), which exposes the cell-scaffold constructs to a wider array of mechanical forces. The pump of the VAD has two chambers: a blood and a pneumatic chamber, separated by an elastic membrane. Pulsatile air-pressure is generated by a piston-type actuator and delivered to the pneumatic chamber, ejecting the fluid in the blood chamber. Subsequently, applied vacuum to the pneumatic chamber causes the blood chamber to fill. A mechanical heart valve was placed in the VAD`s inflow position. The tissue engineered (TE) valve was placed in the outflow position. The VAD was coupled in series with a Windkessel compliance chamber, variable throttle and reservoir, connected by silicone tubings. The reservoir sat on an elevated platform, allowing adjustment of ventricular preload between 0 and 11 mmHg. To allow for sterile gaseous exchange between the circuit interior and exterior, a 0.2 mu m filter was placed at the reservoir. Pressure and flow were registered downstream of the TE valve. The circuit was filled with culture medium and fitted in a standard 5% CO(2) incubator set at 37 degrees C. Pressure and flow waveforms were similar to those obtained under physiological conditions for the pulmonary circulation. The `cardiomimetic` approach presented here represents a new perspective to conventional biomimetic approaches in TE, with potential advantages. Copyright (C) 2010 John Wiley & Sons, Ltd.

Particle-Image Velocimetry Study of a Pediatric Ventricular Assist Device

Particle-image velocimetry (PIV) was used to visualize the flow within an optically transparent pediatric ventricular assist device (PVAD) under development in our laboratory The device studied is a diaphragm type pulsatile pump with an ejection volume of 30 ml per beating cycle intended for temporary cardiac assistance as a bridge to transplantation or recovery in children. Of particular interest was the identification of flow patterns, including regions of stagnation and/or strong turbulence that often promote thrombus formation and hemolysis, which can degrade the usefulness of such devices. For this purpose, phase-locked PIV measurements were performed in planes parallel to the diaphram that drives the flow in the device. The test fluid was seeded with 10 Am polystyrene spheres, and the motion of these particles was used to determine the instantaneous flow velocity distribution in the illumination plane. These measurements revealed that flow velocities up to 1.0 m/s can occur within the PVAD. Phase-averaged velocity fields revealed the fixed vortices that drive the bulk flow within the device, though significant cycle-to-cycle variability was also quite apparent in the instantaneous velocity distributions, most notably during the filling phase. This cycle-to-cycle variability can generate strong turbulence that may contribute to greater hemolysis. Stagnation regions have also been observed between the input and output branches of the prototype, which can increase the likelihood of thrombus formation. [DOI: 10.1115/1.4001252]

Cavopulmonary anastomosis improves left ventricular assist device support in acute biventricular failure

Objective: Right ventricular failure during left ventricular assist device (WAD) support can result in severe hemodynamic compromise with high mortality. This study investigated the acute effects of cavopulmonary anastomosis on right ventricular loading and WAD performance in a model of severe biventricular failure. Methods: LVAD support was performed by means of centrifugal pump implantation in 14 anesthetized dogs (20-30 kg) with severe biventricular failure obtained by ventricular fibrillation induction. Animals were randomized to be submitted to classical cavopulmonary anastomosis (Glenn shunt) or to control group and were maintained under WAD support for 2 h. Left and right atrial, right ventricular and systemic pressures were monitored, white total pulmonary flow was simultaneously recorded by transonic flowmeters located on the superior vena cava and pulmonary trunk. Blood gas and venous lactate determinations were also obtained. Results: Ventricular fibrillation maintenance resulted in acute WAD performance impairment after 90 min in the control group, while animals with Glenn circuit maintained normal WAD pump flow (55 +/- 13 ml kg(-1) min(-1) vs 21 +/- 4 ml kg(-1) min(-1), p < 0.001) and better peripheral perfusion (blood lactate of 29 +/- 10 pg/ml vs 46 +/- 9 pg/ml, p < 0.001). Left and right atrial pressures did not change significantly, while right ventricular pressure was tower in animals with Glenn circuit (13 +/- 3 mmHg vs 22 +/- 8 mmHg, p = 0.005). Right ventricular unloading with Glenn shunt also resulted in superior total pulmonary flow (59 +/- 13 ml kg(-1) min(-1) vs 17 +/- 3 ml kg(-1) min(-1), p < 0.001). Conclusion: The concomitant use of cavopulmonary anastomosis during LVAD support in a model of severe biventricular failure limited right ventricular overloading and resulted in better hemodynamic performance. (C) 2008 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Factors that prevent or assist the integration of assistive technology into the workplace for people with spinal cord injuries: Perspectives of the users and their employers and co-workers

Examined the barriers faced by people with Spinal Cord Injuries (SCI) when integrating their Assistive Technology (AT) into the workplace, as well as factors that contribute to successful integration. In-depth interviews were taken with 5 men (aged 37-50 yrs) with SCI, 3 of their employers and 2 co-workers. Results indicate that in addition to the barriers previously outlined in the literature related to funding the technology, time delays, information availability, training and maintenance, other issues were highlighted. Implications for service providers are considered in relation to these barriers and the factors that prompted successful integration. The author discusses limitations of the study and makes recommendations for future research. (PsycINFO Database Record (c) 2007 APA, all rights reserved)

O censo Suas como processo de aprimoramento e institucionaliza????o da pol??tica de assist??ncia social no Brasil

O Censo Suas ?? um processo de monitoramento que coleta dados por meio de um formul??rio eletr??nico preenchido pelas secretarias e conselhos de Assist??ncia Social. ?? realizado anualmente desde 2007, por meio de uma a????o integrada entre a Secretaria de Assist??ncia Social e a Secretaria de Avalia????o e Gest??o da Informa????o. Esse processo alcan??ou sua maturidade com a incorpora????o de novos question??rios para a coleta de informa????es sobre ??rg??os gestores, Conselhos e entidades privadas de Assist??ncia Social. Em 2010, 99,2% dos munic??pios preencheram 28.519 question??rios. Assim, a Assist??ncia Social aprimorou seu processo de tomada de decis??o, expandindo a rede e a cobertura dos servi??os. Com os indicadores e as metas de desenvolvimento dos Centros de Refer??ncia de Assist??ncia Social (Cras), apurados com base no Censo, foram retroalimentados a????es e projetos de assist??ncia social, institu??dos processos gradativos de adequa????o dos servi??os ??s normas e constitu??dos processos de planejamento para melhoria da gest??o e do controle social do Sistema ??nico de Assist??ncia Social (Suas)

Rede Suas: o sistema nacional de informa????o da assist??ncia social

A Rede SUAS ?? o sistema de informa????o do Sistema ??nico de Assist??ncia Social ??? SUAS e tem a fun????o de responder ??s novas necessidades de informa????o e comunica????o no ??mbito do SUAS, que ?? a regula????o ampliada da Constitui????o Federal de 88, no que tange ?? pol??tica p??blica de assist??ncia social, integrante do sistema brasileiro de seguridade social. Considerada como um instrumento de gest??o colegiada, a Rede SUAS inaugurou para os trabalhadores, gestores e entidades da ??rea, a tarefa de redimensionar a cultura de gest??o, at?? ent??o vivenciada, com a instala????o de aplicativos que geram novos ??ndices de agilidade e transpar??ncia, dando suporte aos processos e procedimentos previstos na Pol??tica Nacional de Assist??ncia Social, 2004, PNAS e na norma operacional b??sica do SUAS/2005. O projeto resolve duas quest??es centrais para a ??rea: a revers??o das tend??ncias que caracterizaram experi??ncias anteriores de gest??o e a necess??ria associa????o dos instrumentos e condi????es tecnol??gicas de produ????o, recebimento, tratamento, armazenamento e entrega de dados e informa????o, com as opera????es de gest??o, financiamento e controle social da pol??tica p??blica de assist??ncia social

A integra????o do Programa Bolsa Fam??lia e da Assist??ncia Social: um olhar sobre a gest??o municipal do Programa

O presente trabalho tem como objetivo entender como se deu a integra????o do Programa Bolsa Fam??lia com a assist??ncia social, tendo em vista que na maior parte dos munic??pios a gest??o do PBF est?? sob a responsabilidade das Secretarias Municipais de Assist??ncia Social. Ao analisar o PBF, foi poss??vel notar duas principais caracter??sticas: 1) descentraliza????o e 2) intersetorialidade. No caso da primeira, as responsabilidades s??o descentralizadas para estados e munic??pios. A implementa????o do PBF dependeu de processos de negocia????o e coordena????o federativa, constru??das a partir de mecanismos volunt??rios de ades??o e pactua????o. J?? com rela????o ?? segunda caracter??stica, o PBF ?? um programa de transfer??ncia de renda com condicionalidades, assim, ele se articula com as ??reas de sa??de e educa????o, que fazem o acompanhamento das condicionalidades das fam??lias benefici??rias. A assist??ncia social tem participa????o nas duas caracter??sticas. Na descentraliza????o, a assist??ncia foi aos poucos incorporando a gest??o municipal do PBF. Quanto ?? integra????o na intersetorialidade do Programa, a assist??ncia social tem o papel de ofertar o acompanhamento familiar ??s fam??lias que n??o cumprem os compromissos da agenda de sa??de ou a frequ??ncia escolar, no acompanhamento das condicionalidades. Para analisar as formas como a assist??ncia social participa da gest??o do PBF foram elaboradas tipologias de estrutura de gest??o do programa. O trabalho tamb??m contou com a an??lise de quatro fontes de dados diferentes: duas quantitativas (Censo SUAS 2011 e Relat??rio de Ades??o dos Munic??pios ao PBF) e duas qualitativas (relat??rios de visitas municipais e question??rios aplicados aos gestores municipais ou t??cnicos do PBF). Com base nas tipologias e nos dados analisados, dentro da assist??ncia foram encontrados tr??s modelos diferentes: gest??o do PBF como uma unidade central no ??rg??o gestor, gest??o do PBF com equipe exclusiva no CRAS e gest??o do PBF sob responsabilidade do PAIF. A partir das pesquisas e das observa????es, foi poss??vel identificar que em 93% dos munic??pios a gest??o do PBF est?? como responsabilidade do ??rg??o gestor da assist??ncia, nos demais a gest??o ?? responsabilidade do gabinete do prefeito ou de outras ??reas, como sa??de, educa????o, finan??as, administra????o ou outras. O trabalho localizou ainda quatro espa??os onde a assist??ncia social participa da gest??o do PBF de forma integrada: 1) Cadastro ??nico, 2) transfer??ncia fundo a fundo para o IGD, 3) Protocolo de Gest??o Integrada de Servi??os Benef??cios e Transfer??ncia de Renda no ??mbito do SUAS, e seus desdobramentos, e 4) presen??a do PBF nas Comiss??es, F??runs e Conselhos de Assist??ncia Social. Ao final, constatou-se que as fontes utilizadas na pesquisa n??o detalham como ?? a participa????o da assist??ncia na gest??o do PBF. Tendo em vista que na maior parte dos munic??pios a assist??ncia ?? a respons??vel pela gest??o do Programa, as considera????es finais trazem a recomenda????o de o Censo SUAS ser o instrumento que pode fornecer insumos para avalia????o de gest??o do PBF, facilitando o planejamento de a????es e di??logos com as equipes municipais

Projeto b??sico: oficina de planejamento estrat??gico para elabora????o do Plano de A????o da Secretaria Nacional de Assist??ncia Social do Minist??rio do Desenvolvimento Social e Combate ?? Fome

Contrata????o de servi??os t??cnicos profissionais especializados de treinamento e aperfei??oamento de pessoal para a realiza????o de Oficina, Sob Medida, de planejamento estrat??gico para elabora????o do Plano de A????o 2013 da Secretaria Nacional Assist??ncia Social (SNAS) do Minist??rio do Desenvolvimento Social e Combate ?? Fome (MDS)

Texto para discuss??o 46: a hegemonia do SUS e a rela????o p??blico/privado na assist??ncia hospitalar

Este artigo procura discutir quest??es sobre o SUS e os limites dos dados dispon??veis para respond??-las, apresentando uma nova agrega????o dos dados de pacientes internados em Belo Horizonte

A implementa????o do sistema ??nico de assist??ncia social nos munic??pios: resultados e determinantes

O objetivo ?? desenvolver uma avalia????o dos resultados da implementa????o municipal da pol??tica de Assist??ncia Social ap??s a cria????o do Sistema ??nico de Assist??ncia Social. Questiona-se se o processo de mudan??a apresenta impacto na melhoria da gest??o municipal, se a cria????o do Sistema surtiu resultados positivos do ponto de vista da equidade entre as prefeituras e quais poss??veis determinantes de eventuais incrementos na execu????o local da assist??ncia social ap??s essa mudan??a institucional. Foram elaborados dois indicadores que procuram refletir aspectos centrais da pol??tica em todos os munic??pios do pa??s: a capacidade administrativa e a provis??o de servi??os assistenciais. Al??m da an??lise explorat??ria desses indicadores, o artigo utiliza an??lise de regress??o m??ltipla para mensurar os determinantes da eventual evolu????o da execu????o municipal da pol??tica. O pressuposto a ser testado ?? de que fatores de natureza pol??tica tamb??m exercem influ??ncia nos desempenhos das prefeituras. Como resultado, a an??lise descritiva indicou que o Sistema foi bem sucedido no incremento das duas dimens??es de AS analisadas, melhorias das regi??es mais pobres do pa??s, como tamb??m na redu????o da disparidade m??dia entre os munic??pios na dimens??o de provis??o de servi??os assistenciais