Analysis of the hydrodynamic profile in different roller pumps models used in cardiopulmonary bypass

OBJECTIVE: Among the equipments used in cardiopulmonary bypass the roller pumps have great importance with various models available from several manufacturers. The calibration is an important factor in hemolysis rates and its potential is different in each. Researchers do not always approach details on the pump bed profiles assuming that the standardized calibration settings ensure equal and comparable values for all models of roller pumps. We have mainly two methods for calibration of pumps which also interferes on the hemolytic potential. In both of them, the characteristics of fluid impulsion defined by the pump bed design are not considered. The aim of this study is to compare the hydrodynamic profile of three models of roller pumps available in the Brazilian market. METHODS: The rollers occlusion was performed by measures of drop and dynamic calibration. Two different silicone diameter tubes were used (3/8 x 1/16 and 1/2 x 3/32 inches). RESULTS: The profiles showed differences in their variances, P<0.01 for drop rate measures and P<0.0001 for dynamic calibration. Different changes in pressure were found between the pumps analyzed (P<0.002). CONCLUSION: The measures of occlusion are dependent on the design of the pump bed and comparisons involving roller pumps should be performed with caution. Blood tests should be performed to verify the influence of changes in hemolysis pressure.OBJETIVO: Dentre os equipamentos utilizados em circulação extracorpórea, as bombas de rolete têm grande importância, com diversos modelos disponíveis de vários fabricantes. A calibração é um fator importante nas taxas de hemólise e o seu potencial difere em cada uma delas. Pesquisadores nem sempre abordam detalhes sobre os perfis do leito rígido, supondo que as formas padronizadas de calibração garantem valores iguais e comparáveis para todos os modelos de bombas de rolete. Dispomos principalmente de dois métodos para a calibração das bombas, o que também interfere com o potencial hemolítico. Nenhum dos métodos considera as características de impulsão do fluído, definido pela forma construtiva do leito rígido. O objetivo é avaliar o perfil hidrodinâmico de três modelos de bombas de roletes disponíveis no mercado brasileiro. MÉTODOS: A oclusão dos roletes foi feita por medidas de velocidade de queda e calibração dinâmica. Foram utilizados dois diferentes diâmetros de tubos de silicone (3/8 x 1/16 e 1/2 x 3/32 polegadas). RESULTADOS: Os perfis apresentaram diferenças em suas variâncias. P<0,01 para medidas de velocidade de queda e P<0,0001 para medidas de calibração dinâmica. Foram encontradas diferenças nas variações de pressão entre as bombas analisadas (P<0,002). CONCLUSÃO: As medidas de oclusão são dependentes da forma do leito rígido e comparações envolvendo bombas de rolete devem ser feitas com cautela. Testes com sangue deveriam ser realizados para verificar a influência das variações de pressão na hemólise.18819

Hemodynamic Disorders Related To Beating Heart Surgery Using Cardiac Stabilizers: Experimental Study.

To study in swine the hemodynamic changes secondary to the use of stabilizers for off-pump coronary artery bypass graft surgeries by means of both a suction device Octopus and a compression device (Speroni). Ten swine underwent median sternotomy. Monitoring of ECG, continuous cardiac output, mean arterial pressure, mean pulmonary artery pressure, mean right and left atrial pressures, and right and left ventricular diastolic pressure were performed. Stroke volume and systemic vascular resistance were calculated. Both stabilizers were studied placed on three vessels: anterior interventricular branch, posterior interventricular branch, and marginal branch of the circumflex branch. Each animal was randomly designed to application regarding the type of stabilizer and the target artery. The measurements were carried out 5 minutes before and after the stabilizer application. In the anterior interventricular branch changes have occurred only with the compression device, thus reducing cardiac output, stroke volume, and mean arterial pressure, but increasing the systemic vascular resistance. In the posterior interventricular branch changes have occurred with the compression device (Speroni), reducing cardiac output and stroke volume, but increasing the heart rate. With the suction device (octopus) there was an increase of both heart rate and systemic vascular resistance, but a decrease in stroke volume. In the marginal branch of the circumflex branch there was a decrease of cardiac output, stroke volume, and mean arterial pressure with both stabilizers. Also, there was a decrease in the mean pulmonary artery pressure and an increase in the mean right atrial pressure with the compression device (Speroni). Both stabilizers have caused hemodynamic changes. The compression device (Speroni) is more associated with changes than the suction device (Octopus).22407-1

Operation and performance of the ATLAS Tile Calorimeter in Run 1

The Tile Calorimeter is the hadron calorimeter covering the central region of the ATLAS experiment at the Large Hadron Collider. Approximately 10,000 photomultipliers collect light from scintillating tiles acting as the active material sandwiched between slabs of steel absorber. This paper gives an overview of the calorimeter’s performance during the years 2008–2012 using cosmic-ray muon events and proton–proton collision data at centre-of-mass energies of 7 and 8TeV with a total integrated luminosity of nearly 30 fb−1. The signal reconstruction methods, calibration systems as well as the detector operation status are presented. The energy and time calibration methods performed excellently, resulting in good stability of the calorimeter response under varying conditions during the LHC Run 1. Finally, the Tile Calorimeter response to isolated muons and hadrons as well as to jets from proton–proton collisions is presented. The results demonstrate excellent performance in accord with specifications mentioned in the Technical Design Report

Desenvolvimento e padronização de modelo experimental com coração isolado de suinos utilizando circulação parabiotica

Orientador : Domingo Marcolino BraileDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências MédicasResumo: o desenvolvimento de modelos experimentais permitem o estudo de diferentes fánnacos ou elucidação de fenômenos observados na prática clínica.O modelo de corações isolados tem sido a base para a investigação de fenômenos no miocárdio. A utilização de corações perfundidos por sangue tem vantagens sobre os modelos perfundidos por soluções cristalóides. A utilização de circulação cruzada (parabiótica) entre um anima1suporte e o coração isolado de um segundo animal foi descrita no início deste século. Contudo, só mais recentemente este modelo vem sendo usado e pouca descrição sobre os seu preparo e variáveis do modelo são encontradas na literatura. Objetivo: Descrever e padronizar modelo experimental com circulação parabiótica de coração isolado em SUÍnos Metodologia: Utilizamos suinos para desenvolver modelo de coração isolado perfundido por sangue. O coração isolado é perfundido com sangue arterial de um segundo animal suporte. O coração isolado foi submetido a isquemia regional durante 30 minutos, seguido de isquemiaglobal por 90 minutos e reperfusão por mais 90 minutos. No coração isolado foram definidos parâmetros úteis para a mensuração do desempenho ventricuJar com diferentes índices medidos diretamente ou indiretamente da pressão intraventricuJar. Resultados: O coração submetido a isquemia regional e global apresentou piora na maioria dos parâmetros medidos. Os parâmetros menos discriminativos foram a dP/dTmáxnormalizada pela pressão desenvolvida e a dP/dT minnorma ~dapela pressão desenvolvida.A elastância foi o parâmetro mais sensível durante o período de reperfusão, demonstrando perda da função ventricu1armuito precocemente na reperfusão. Conclusões: o modelo demonstrou-seestável, reprodutívele permite estudo de diversas variáveis no coraçãoisolado. A preparação desenvolvida permite o estudo de fenômenos de isquemia e reperfusão, os mais diferentes fármacos, intervenções cirúrgicas. Apresenta vantagens sobre os modelos clássicos que utilizam soluções cristalóides como perfusato, pois a utilização de circulação parabiótica coloca o coração isolado muito próximo daquele que é submetido a cirurgia cardíaca com circulação extracorpóreaAbstract: The experimental models development allow to study di:fferent drogs or elucidation of different pbenomena observed in the clinical practice. The isolated hearts model has been being the base for myocardium phenomena investigation .The blood perfused hearts has advantages on the crystalloid perfused isolated hearts .The cross circulation utilization (parabiotic) between an support anima1and the isolated heart ftom second anim was describe at the beginning of this century. However, more recently this model has been used and little description 3OOutyour prepare and variables of the model are found in the literature. Objective: Describe and to standardize experimental model with parabiotic circulation of iso1atedheart in swines. Methodology: We use swines to develop isolated blood perfused heart modeL The isolated heart is perfused with arterial blood ftom second anima1as support. The isolated heart was submitted regional ischaemia for 30 minutes, followed by global ischaemia for 90 minutes and reperfusion plus 90 minutes. In the isolated heart were going defined useful parameters for measurement of the ventricuJar performance with di:fferent measured índices directly or indirectly ftom mtraventricular pressure . Results: The submitted isolated hearts to regional and global ischaemia presented worsening in the measured parameters majorlty. The less discriminative parameters went to dP/dT máx normalized by the developedpressureanddP/dTminnormalizedbythe developedpressure. Elastance was the most sensible parameter during reperfusion period, demonstrating ventricular function loss much precociously in reperfusion. Conclusions: The model it demonstrated stable, reproducible and allows severa! variables study in the isolated heart. The developed preparation allows study of ischaemia and reperfusion phenomena, the most different drugs, surgical interventions, etc. It introduces advantages on the classical models which use crystal1oidsolutions how perfusate, because the parabiotic circulation utilization places the isolated heart very elose to which is submitted to cardiac surgery with extracorporeal circulationMestradoMestre em Cirurgi

Estudo comparativo entre solução cardioplegica cristaloide e microcardioplegia sanguinea normotermica em corações agudamente isquemico

Orientador: Domingo Marcolino BraileTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias MedicasResumo: Introdução: Diversos métodos de proteção miocárdica tem sido utilizados. O uso de soluções sanguíneas modificadas com glutarnato e aspartato tem aumentado. Sua utilização em situações de isquemia aguda possibilita uma melhora da função contrátil, "ressuscitando" músculo préviamente lesado. A diluição preconizada na literatura está ao redor de 25% de hematócrito. O presente trabalho avalia solução cardioplégica sanguínea com diluição de 1% em normotermia, denominada microcardioplegia. Material e Método: Foram utilizados suínos da raça Large-White com modelo de coração isolado perfundido por sangue de animal suporte. Foram designados 3 grupos (n = 7 por grupo) com os seguintes tratamentos: Grupo controle (CO), solução St Thomas (ST), solução sanguínea contínua normotérmica (SG). Após um período de estabilização medidas de pressão sistólica (PS), pressão diastólica (PD), pressão desenvolvida (PD), stress (cr)da parede, elastância, rigidez passiva eram realizadas. Os corações eram submetidos a 30 minutos de isquemiaregional com o pinçamento da artéria interventricular anterior e, então, a noventa minutos de isquemia global empregando-se os três diferentes tratamentos neste período. No início da isquemia global a pinça da coronária era retirada. Os corações eram novamente reperfundidos. Após 3 minutos de reperfusão eram desfibrilados, quando necessário. Medidas eram realizadas a cada 30 minutos, até noventa minutos de reperfusão. Resultados: O grupo SG apresentou melhor recuperação da função ventricular em diversos parâmetros mensurados. O grupo ST foi inferior ao grupo SG, mas foi superior ao grupo CO em alguns parâmetros analisados. Houve maior necessidade de desfibrilações para o restabelecimentodos batimentos coordenados nos grupos ST eCO. Não houve diferença quanto à porcentagem de peso úmido entre os grupos SG e ST, mas foi maior no grupo CO. Conclusão: A utilização de microcardioplegia sanguínea promove proteção supenor quando comparado a isquemia global ou cardioplegia cristalóide em corações agudamente isquêmicos. O modelo empregado está muito próximo da situação clínica por utilizar sangue como perfusatoAbstract: Objective: There are several methods of myocardial protection. Blood solutions modified with glutamate and aspartate are increasingly being used and in the case of acute ischemia, they enhance the contractile function 'resuscitating' the injured musc1e. The dilution recommended in the literature is approximately 25% of the hematocrit. This present study evaluates a 1% diluted normothermic blood cardioplegic solution denominated "microcardioplegia". Materiais and Methods: In this study, Large-White pigs were used as models of an isolated heart perfused by blood from the support animal. The animals were designated into three groups with seven animaIs per group (n=7) and the following treatments were applied: Control Group (CO), 8t. Thomas solution (ST), continuous normothermic blood solution (8G). After a period of stability, the following measurements were taken: systolic pressure (SP), diastolic pressure (DP), developed pressure (DP), wall stress (0"),elasticity and passive rigidity. The hearts were subjected to 30 minutes of regional ischemia by c1ampingthe anterior interventricular artery and then 90 minutes of global ischemia during which the three above specified treatments were applied. The coronary c1ampwas removed at onset of global ischemia. The hearts were once again reperfused and after three minutes of reperfusion were defibrillated whenever needed. Measurements were taken every 30 minutes for up to 90 minutes of reperfusion. Results: The SG group presented the best recovery ofventricular function in relation to the various parameters measured. The performance of the ST group was inferior to tOOtof the SG group, but was superior to the CO group with regard to some of the parameters. The need for defibrillation to reestablish heart rate was higher in the ST and CO groups. No difference was observed between the groups SG and ST with regard to percentage of weight ofhumidity, but it was higher in the CO group. Conclusion: The use of blood microcardioplegia promotes greater protection in acute ischemic hearts when compared with global ischemia or crystalloid cardioplegia. The model used in this study is very similar to the actual clinicalcondition as it utilizes blood as the perfusateDoutoradoDoutor em Cirurgi

The effect on hemolysis of the raceway profile of roller pumps used in cardiopulmonary bypass

This study aims at the influence on hemolysis of the differences between the maximum and minimum amplitudes of pressure in the outlet of three roller pump models adjusted by dynamic calibration method. Tests were performed with silicone tubes (1/2 x 3/16 inches) in fluid analogous to blood and fresh bovine blood from slaughterhouse. Tests with analogous solution to blood were performed varying the dynamic calibration pressure between 78 and 500 mm Hg. Tests with fresh bovine blood were performed with the three pumps simultaneously, and pressure differences and free hemoglobin in the plasma were measured during 360 minutes. Tests with both analogous solution to blood and fresh bovine blood showed differences of mean pressures of pump 2 related to pumps 1 and 3 (p < 0.01). The different models of roller pumps analyzed presented differences in pressure amplitudes (p < 0.01) and hemolysis (p < 0.01) adjusted for the same dynamic calibration pressure. Raceway profile of pump 2 resulted in smaller pressure amplitude, implying lower hemolysis rate compared with pumps 1 and 35814045School of Medical Sciences, University of Campinas (UNICAMP), Campina

Postoperative Period of Myocardial Revascularization Surgery: Retrospective Cohort Study of a Single Center

ABSTRACT Introduction: Risk factors and postoperative complications can worsen the condition of patients undergoing coronary artery bypass grafting; some of these factors and complications are closely related to mortality rate. Objective: To describe clinical factors and outcomes related to mortality of patients undergoing coronary artery bypass grafting and on invasive mechanical ventilation. Methods: This is a single-center retrospective data analysis of patients who underwent coronary artery bypass grafting on invasive mechanical ventilation between 2013 and 2019. Data regarding clinical characteristics, postoperative complications, intensive care unit and mechanical ventilation time, and their relationship with mortality were analyzed. Results: Four hundred seventy-two patients who underwent coronary artery bypass grafting entered the study. Their mean age was 62.3 years, and mean body mass index was 27.3. The mortality rate was 4%. Fifty percent of the patients who had ventilator-associated pneumonia died. Considering the patients who underwent hemotherapy and hemodialysis, 20% and 33% died, respectively. Days of intensive care unit stay and high Acute Physiology and Chronic Health Evaluation score and Simplified Acute Physiology Score were significantly related to death. Conclusion: Factors and clinical conditions such as the patients’ age, associated comorbidities, the occurrence of ventilator-associated pneumonia, length of stay in the intensive care unit, and mechanical ventilation time are related to higher mortality in patients undergoing coronary artery bypass grafting