Introduction: Venoarterial extracorporeal membrane oxygenation (VA ECMO) is widely used in the treatment of circulatory failure, but repeatedly, its negative effects on the left ventricle (LV) have been observed. The purpose of this study is to assess the influence of ex- tracorporeal blood flow (EBF) on systemic hemodynamic changes and LV performance parameters during VA ECMO therapy of decompensated heart failure. Methods: Porcine models of low-output chronic and acute heart failure were developed by long-term fast cardiac pacing and coronary hypoxemia, respectively. Profound signs of circulatory decompensation were defined by reduced cardiac output and tissue hypoperfusion. Sub- sequently, under total anesthesia and artificial ventilation, VA ECMO was introduced. LV performance and organ specific parameters were recorded at different levels of EBF using an LV pressure-volume loop analysis, arterial flow probes on carotid and subclavian arteries, and transcutaneous probes positioned to measure cerebral and forelimb regional tissue oxygen saturations. Results: Conditions of severely decompensated heart failure led to systemic hypotension, low tissue and mixed venous oxygen saturations, and increase in LV end-diastolic pressure. By increasing the EBF from minimal flow to 5 L/min, we observed a...

Mortality in infarct-related cardiogenic shock (CS) remains high, reaching 40–50%. In refractory CS, active mechanical circulatory support devices including veno-arterial extracorporeal membrane oxygenation (VA-ECMO) are rapidly evolving. However, supporting evidence of VA-ECMO therapy in infarct-related CS is low. The current review aims to give an overview on the basics of VA-ECMO therapy, current evidence, ongoing trials, patient selection and potential complications.

Current Possibilities in Use of a Centrifugal Pump in the Cardiac Sugery Abstract Currently, the most commonly used technical solution for pumping blood during extracorporeal circulation during cardiac surgery, as well as for some types of ECMO (extracorporeal membrane oxygenation) are either a roller pump or centrifugal pump. Due to its advantages the centrifugal pump is mainly used for prolonged extracorporeal circulation in cardiac surgery and as a heart and / or lung support system. In current literature there is a lack of compelling scientific evidence that would clearly support its use in a routine cardiac surgery. The aim of our study was to compare both types of currently used blood pumps in longer cardiac procedures with deep hypothermic circulation arrest. In a randomized clinical study we had selected a group of patients that underwent a pulmonary endarterectomy (PEA) in order to demonstrate the positive effects of the centrifugal pump on the postoperative inflammatory reactions. There were no statistically significant differences between these two pumps when other clinical and laboratory parameters were observed. Based on the hypothesis that significant temperature changes during cardiac procedure with a deep hypothermia can affect sealing pressure of the endotracheal tube cuff, we performed a...

Current Possibilities in Use of a Centrifugal Pump in the Cardiac Sugery Abstract Currently, the most commonly used technical solution for pumping blood during extracorporeal circulation during cardiac surgery, as well as for some types of ECMO (extracorporeal membrane oxygenation) are either a roller pump or centrifugal pump. Due to its advantages the centrifugal pump is mainly used for prolonged extracorporeal circulation in cardiac surgery and as a heart and / or lung support system. In current literature there is a lack of compelling scientific evidence that would clearly support its use in a routine cardiac surgery. The aim of our study was to compare both types of currently used blood pumps in longer cardiac procedures with deep hypothermic circulation arrest. In a randomized clinical study we had selected a group of patients that underwent a pulmonary endarterectomy (PEA) in order to demonstrate the positive effects of the centrifugal pump on the postoperative inflammatory reactions. There were no statistically significant differences between these two pumps when other clinical and laboratory parameters were observed. Based on the hypothesis that significant temperature changes during cardiac procedure with a deep hypothermia can affect sealing pressure of the endotracheal tube cuff, we performed a...

Introduction: Left-ventricular (LV) distension and consequent pulmonary congestion are complications frequently discussed in patients with severe LV dysfunction treated with veno- arterial extracorporeal membrane oxygenation (VA ECMO). The goal of this study was to describe the influence of high VA ECMO flows to LV distension, lung hemodynamics, and lung fluid accumulation. Methods of LV decompression were studied to prevent lung edema. Methods: In all experiments porcine models under general anesthesia were used. The effects of high extracorporeal blood flow (EBF) on LV heart work were assessed in a chronic heart failure model. The effects of LV afterload on lung fluid accumulation were evaluated by electrical impedance tomography (EIT) on acute heart failure models. Phase and frequency filtration and mathematical analysis were applied to the raw EIT data. Subsequently, mini- invasive techniques of LV decompression were evaluated for LV work. Results: The stepwise increases of VA ECMO flow improved both hemodynamic and oxygenation parameters. Nevertheless, it also caused distension and increased work of LV. The rise in EBF led to increased pulmonary capillary wedge pressure and lung fluid accumulation assessed by EIT in heart failure. The methods for LV decompression (Impella pump, atrial...

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Made available in DSpace on 2016-01-26T12:51:54Z (GMT). No. of bitstreams: 1 josefranciscogandolfi_tese.pdf: 946147 bytes, checksum: 007d161afcdde952537f95c14f87bb0c (MD5) Previous issue date: 2006-03-06 / Introduction: Extracorporeal pulmonary assistance has been proposed as an invasive alternative to the conventional treatment when adequate oxygenation becomes impossible by mechanical ventilation. Extracorporeal membrane oxygenation (ECMO) attained using assisted circulation may cause hemolysis, coagulation disorders, an inflammatory response and complications inherent to a high-risk high-cost procedure. The objective of this work was to evaluate the efficacy, both in vitro and ex vivo, of a low-resistance oxygenator in ECMO without assisted circulation. Material and Method: Initially, different prototypes of the low-resistance membrane oxygenator were developed to test the influence of the of inlet and outlet conditions of the blood, the area, the quantity and placement of the fibers in the oxygenation process and the removal of carbon dioxide gas (CO2). In the in vitro tests when bovine blood was utilized, the mean flow, volume of blood needed to fill the oxygenator and for priming, oxygen saturation, carbon dioxide gas exchange and the pressure gradient were measured. For the ex vivo experiments, five Santa Inês sheep, weighing between 5 and 33 kg, were used. In each animal, variations in respect to the oxygen saturation, the PO2 and the PCO2 were studied in the systemic blood at the outlet of the oxygenator and of the venous blood using oxygen flow rates of 0.5L/min, 1.0 L/min and 1.5 L/min. Results: The oxygenator had an excellent mechanical performance, which was seen by the PO2, PCO2 and oxygen saturation of the blood at the outlet of the oxygenator. From the clinical point of view, the improvement in the PO2 and oxygen saturation and the reduction in PCO2 of the systemic arterial blood (femoral artery of the sheep), were evident in the five sheep. A tendency of better results was seen when the weight was less than 10kg. Translating these relationships in terms of blood flow and total volume, the best results appeared when the blood flow in the oxygenator/volume proportion was 20% or greater, establishing this cutoff point as the ideal flow necessary for the best performance of the oxygenator. Conclusion: The in vitro and ex vivo performance tests achieved with the low-resistance membrane oxygenator used in arteriovenous extracorporeal circulation without the assistance of a propulsion pump, proved that this device is capable of providing oxygen and removing carbon dioxide from the blood in sufficient quantities to maintain the tested parameters at acceptable limits when ventilation is prejudiced. / Introdução: A assistência pulmonar extracorpórea tem sido proposta como uma alternativa invasiva ao tratamento convencional, quando a oxigenação adequada torna-se impossível pelo uso de ventilação mecânica. A oxigenação extracorpórea por membrana (ECMO) realizada com auxílio circulatório pode produzir hemólise, distúrbios da coagulação, resposta inflamatória e complicações inerentes a um procedimento de alto risco e elevado custo. O objetivo deste trabalho foi avaliar a eficácia in vitro e ex vivo de um oxigenador de baixa resistência em ECMO sem auxílio circulatório. Material e Método: Inicialmente foram desenvolvidos diferentes protótipos do oxigenador de membrana de baixa resistência para testar a influência das condições de entrada e saída do sangue, área, quantidade e disposição das fibras no processo de oxigenação e remoção de gás carbônico (CO2). Nos testes in vitro, utilizando-se sangue bovino, foram avaliados fluxo médio, volume de sangue necessário para preencher o oxigenador ou priming, saturação de oxigênio e transferência de gás carbônico e o gradiente de pressão. Nos experimentos ex vivo foram utilizados cinco carneiros da raça Santa Inês, pesando entre 5 a 33 Kg. Em cada animal foram estudadas as variações com relação à saturação de O2, PO2 e PCO2, no sangue sistêmico, na saída do oxigenador e no sangue venoso com fluxos de oxigênio no oxigenador 0,5 L/min, 1,0 e 1,5 L/min. Resultados: O oxigenador demonstrou excelente desempenho mecânico, o que pode ser verificado pelos valores de PO2, PCO2 e SatO2 do sangue na saída do oxigenador. Do ponto de vista clínico, a melhora de PO2 e SO2 e a redução de PCO2 no sangue arterial sistêmico (artéria femoral do carneiro) foram evidentes nos cinco experimentos. Foi possível observar uma tendência para melhores resultados com pesos inferiores a 10,0 kg. Traduzindo-se essas relações em termos de fluxo sanguíneo e volemia total, os melhores resultados apareceram com proporção fluxo sangüíneo no oxigenador/volemia, de 20% ou maior, podendo-se estabelecer esse limite de corte, como fluxo ideal necessário para bom desempenho do oxigenador. Conclusão: Os testes de performance in vitro e desempenho ex vivo, realizados com o oxigenador de membrana de baixa resistência ao fluxo, para uso em circulação extracopórea arteriovenosa, sem o auxílio de bomba propulsora, mostraram resultados suficientes para concluir que tais dispositivos são capazes de fornecer Oxigênio e retirar gás Carbônico do sangue em quantidades suficientes para manter tais parâmetros em níveis aceitáveis, quando a ventilação está prejudicada.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.