Thermo-electric energy storage using co2 transcritical cycles and ground heat storage

Multi-megawatt thermo-electric energy storage based on thermodynamic cycles is a promising alternative to PSH (Pumped-Storage Hydroelectricity) and CAES (Compressed Air Energy Storage) systems. The size and cost of the heat storage are the main drawbacks of this technology but using the ground as a heat reservoir could be an interesting and cheap solution. In that context, the aim of this work is i) to assess the performance of a massive electricity storage concept based on CO2 transcritical cycles and ground heat exchangers, and ii) to carry out the preliminary design of the whole system. This later includes a heat pump transcritical cycle as the charging process and a transcritical Rankine cycle of 1 – 10 MWe as the discharging process. A steady-state thermodynamic model is realized and several options, including regenerative or multi-stage cycles, are investigated. In addition, a one-dimensional design model of the geothermal heat exchanger network is used to optimize the number of wells for the ground heat storage. The results show the strong dependency between the charging and discharging cycles, and how the use of regenerative heat exchangers and a two-phase expander (in the charging cycle) could increase the system efficiency and lower the investment cost.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Pre-ejection period by radial artery tonometry supplements echo doppler findings during biventricular pacemaker optimization

<p>Abstract</p> <p>Background</p> <p>Biventricular (Biv) pacemaker echo optimization has been shown to improve cardiac output however is not routinely used due to its complexity. We investigated the role of a simple method involving computerized pre-ejection time (PEP) assessment by radial artery tonometry in guiding Biv pacemaker optimization.</p> <p>Methods</p> <p>Blinded echo and radial artery tonometry were performed simultaneously in 37 patients, age 69.1 ± 12.8 years, left ventricular (LV) ejection fraction (EF) 33 ± 10%, during Biv pacemaker optimization. Effect of optimization on echo derived velocity time integral (VTI), ejection time (ET), myocardial performance index (MPI), radial artery tonometry derived PEP and echo-radial artery tonometry derived PEP/VTI and PEP/ET indices was evaluated.</p> <p>Results</p> <p>Significant improvement post optimization was achieved in LV ET (286.9 ± 37.3 to 299 ± 34.6 ms, p < 0.001), LV VTI (15.9 ± 4.8 cm to 18.4 ± 5.1 cm, p < 0.001) and MPI (0.57 ± 0.2 to 0.45 ± 0.13, p < 0.001) and in PEP (246.7 ± 36.1 ms to 234.7 ± 35.5 ms, p = 0.003), PEP/ET (0.88 ± 0.21 to 0.79 ± 0.17, p < 0.001), and PEP/VTI (17.3 ± 7 to 13.78 ± 4.7, p < 0.001). The correlation between comprehensive echo Doppler and radial artery tonometry-PEP guided optimal atrioventricular delay (AVD) and optimal interventricular delay (VVD) was 0.75 (p < 0.001) and 0.69 (p < 0.001) respectively. In 29 patients with follow up assessment, New York Heart Association (NYHA) class reduced from 2.5 ± 0.8 to 2.0 ± 0.9 (p = 0.004) at 1.8 ± 1.4 months.</p> <p>Conclusion</p> <p>An acute shortening of PEP by radial artery tonometry occurs post Biv pacemaker optimization and correlates with improvement in hemodynamics by echo Doppler and may provide a cost-efficient approach to assist with Biv pacemaker echo optimization.</p

Simple scoring system to predict in-hospital mortality after surgery for infective endocarditis

BACKGROUND: Aspecific scoring systems are used to predict the risk of death postsurgery in patients with infective endocarditis (IE). The purpose of the present study was both to analyze the risk factors for in-hospital death, which complicates surgery for IE, and to create a mortality risk score based on the results of this analysis. METHODS AND RESULTS: Outcomes of 361 consecutive patients (mean age, 59.1\ub115.4 years) who had undergone surgery for IE in 8 European centers of cardiac surgery were recorded prospectively, and a risk factor analysis (multivariable logistic regression) for in-hospital death was performed. The discriminatory power of a new predictive scoring system was assessed with the receiver operating characteristic curve analysis. Score validation procedures were carried out. Fifty-six (15.5%) patients died postsurgery. BMI >27 kg/m2 (odds ratio [OR], 1.79; P=0.049), estimated glomerular filtration rate 55 mm Hg (OR, 1.78; P=0.032), and critical state (OR, 2.37; P=0.017) were independent predictors of in-hospital death. A scoring system was devised to predict in-hospital death postsurgery for IE (area under the receiver operating characteristic curve, 0.780; 95% CI, 0.734-0.822). The score performed better than 5 of 6 scoring systems for in-hospital death after cardiac surgery that were considered. CONCLUSIONS: A simple scoring system based on risk factors for in-hospital death was specifically created to predict mortality risk postsurgery in patients with IE

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure &lt; 100 mmHg (n = 1127), estimated glomerular filtration rate &lt; 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Aspergillose invasive chez l'immunocompétent en réanimation (à propos de deux cas)

L'aspergillose invasive (AI) en réanimation chez l'immunocompétent a une incidence mal connue et une mortalité élevée. Le diagnostic est difficile : clinique aspécifique, imagerie et histologie de réalisation délicate, outils biologiques non validés. Nous présentons dans ce travail les cas de deux patients immunocompétents décédés d'AI après un choc septique. Chez l'immunocompétent, le caractère nosocomial de l'AI est controversé. Une colonisation communautaire avec invasion à l'occasion de l'altération de l'immunité n'est pas exclue. De nouveaux facteurs de risque sont discutés : pathologie pulmonaire chronique, cirrhose, corticoïdes, catécholamines et surtout immunisupression post-agressive. Chirurgie, sepsis, états de choc, polytraumatisme sont autant de situations à risque. Le monitorage du statut immunitaire (dosage des récepteurs mHLA-DR, polymorphisme des récepteurs à Aspergillus) permettra peut-être dans l'avenir d'identifier les hôtes potentiels en vue d'une immunothérapie.RENNES1-BU Santé (352382103) / SudocSudocFranceF

Étude du couplage ventriculo-artériel à l'effort chez les insuffisants cardiaques à fraction d'éjection conservée et altérée

Introduction : L'insuffisance cardiaque (IC) est associée à des anomalies de la fonction ventriculaire et vasculaire entraînant un couplage ventriculo-artériel défavorable. L'objectif de ce travail et d'analyser l'adaptation de ces paramètres à l'effort chez des IC systolique (IC-Sys) et à fraction d'éjection conservée (IC-FEc) en les comparant à une population témoin. Matériel et méthode : Un groupe de 15 témoins a été comparé à 23 IC-FEc (FEVG>45%) et 23 IC-Sys (FEVG < 30%) stables, traités, en rythme sinusal, au repos et pendant un effort de 30 W en position couchée. La relation pression volume télésystolique (RPVTS) a été approchée par le calcul des élastances télésystolique (Ees) et artérielle (Ea) par échographie. Les pressions de remplissage et la relaxation ventriculaire ont été évaluées par Doppler tissulaire et la fonction vasculaire carotidienne par le module élastique de Peterson (Ep). Résultats : Les IC-Sys étaient plus jeunes avec des pressions artérielles (PA) basses et les IC-FEc étaient plus hypertendus. Les IC présentent plus de facteurs de risque cardiovasculaire et une thérapeutique cardiovasculaire plus importante par rapport aux témoins. Les IC étaient peu différents des témoins au repos, en terme de post-charge (Ea, Ep). La contractilité était abaissée chez les IC-Sys et quelque que soit la FEVG, les IC ont des pressions de remplissage élevées au repos. A l'effort, les IC-FEc révèlent une augmentation majeure de la rigidité vasculaire proximale (Ep : 1,96+-0,33 vs 4,28+-0,33 kPa10 , p<0,05), sans réserve en précharge, ceci étant partiellement compensé par l'utilisation de leur réserve contractile. La RPVTS est déviée vers le haut chez les IC-FEc, et en haut à droite chez les témoins révélant une adaptation par les conditions de charge. Les IC-Sys révèlent une augmentation intermédiaire de la rigidité vasculaire proximale, sans réserve en précharge, compensée par l'utilisation de leur réserve contractile. La RPVTS est déviée vers le haut et la gauche chez les IC-FEc. Conclusion : Cette étude montre pour la première fois que les IC démasquent une rigidité artérielle proximale augmentée à l'effort, susceptible d'altérer le couplage ventriculo-artériel. Ce phénomène est prépondérant chez les IC-FEc. La réserve contractile des patients IC est présente et utilisée précocement en raison de l'absence de réserve de précharge.AMIENS-BU Santé (800212102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Etude du couplage ventriculo artériel chez l'insuffisant cardiaque chronique stable par le système SphygmoCor

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF