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https://www.readbyqxmd.com/read/29629989/an-open-loop-physiologic-model-based-decision-support-system-can-provide-appropriate-ventilator-settings
#1
Dan Stieper Karbing, Savino Spadaro, Nilanjan Dey, Riccardo Ragazzi, Elisabetta Marangoni, Francesca Dalla Corte, Federico Moro, David Lodahl, Niklas Schurmann Hansen, Robert Winding, Stephen Edward Rees, Carlo Alberto Volta
OBJECTIVES: To evaluate the physiologic effects of applying advice on mechanical ventilation by an open-loop, physiologic model-based clinical decision support system. DESIGN: Prospective, observational study. SETTING: University and Regional Hospitals' ICUs. PATIENTS: Varied adult ICU population. INTERVENTIONS: Advice were applied if accepted by physicians for a period of up to 4-8 hours. MEASUREMENTS AND MAIN RESULTS: Seventy-two patients were included for data analysis...
April 6, 2018: Critical Care Medicine
https://www.readbyqxmd.com/read/29617382/measuring-co2-and-ch4-with-a-portable-gas-analyzer-closed-loop-operation-optimization-and-assessment
#2
Jeremy Wilkinson, Christoph Bors, Florian Burgis, Andreas Lorke, Pascal Bodmer
The use of cavity ring-down spectrometer (CRDS) based portable greenhouse gas analyzers (PGAs) in closed-loop configuration to measure small sample volumes (< 1 l) for CH4 and CO2 concentrations is increasing and offers certain advantages over conventional measurement methods in terms of speed as well as the ability to measure directly in field locations. This first systematic assessment of the uncertainties, problems and issues associated with achieving reliable and repeatable measurement with this technique presents the adaptation, measurement range, calibration and maintenance, accuracy and issues of efficient operation, for one example instrument...
2018: PloS One
https://www.readbyqxmd.com/read/29570208/sheep-can-be-used-as-animal-model-of-regional-myocardial-remodelling-and-controllable-work
#3
Jürgen Duchenne, Piet Claus, Efstathios D Pagourelias, Razvan O Mada, Joeri Van Puyvelde, Kathleen Vunckx, Eric Verbeken, Olivier Gheysens, Filip Rega, Jens-Uwe Voigt
BACKGROUND: A-V-sequential pacing has been shown to induce reversible conduction delay and subsequent asymmetric remodelling of the left ventricle (LV) in dogs and pigs. Both species have disadvantages in animal experiments. Therefore aim of this study focusses at developing a more feasible and easy-to-use animal model in sheep. METHODS: Dual-chamber pacing (DDD) pacemakers (right atrium + right ventricular free wall) were surgically implanted in 13 sheep. All animals underwent 8 weeks of chronic rapid pacing at 180 bpm...
March 23, 2018: Cardiology Journal
https://www.readbyqxmd.com/read/29551977/high-spatial-resolution-multi-organ-finite-element-modeling-of-ventricular-arterial-coupling
#4
Sheikh Mohammad Shavik, Zhenxiang Jiang, Seungik Baek, Lik Chuan Lee
While it has long been recognized that bi-directional interaction between the heart and the vasculature plays a critical role in the proper functioning of the cardiovascular system, a comprehensive study of this interaction has largely been hampered by a lack of modeling framework capable of simultaneously accommodating high-resolution models of the heart and vasculature. Here, we address this issue and present a computational modeling framework that couples finite element (FE) models of the left ventricle (LV) and aorta to elucidate ventricular-arterial coupling in the systemic circulation...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29548538/right-heart-function-interacts-with-left-ventricular-remodeling-after-crt-a-pressure-volume-loop-study
#5
Alexander Schmeisser, Thomas Rauwolf, Ali Ghanem, Thomas Groscheck, Daniela Adolf, Frank Grothues, Katharina Fischbach, Ortrud Kosiek, Christof Huth, Siegfried Kropf, Stefan Lange, Blerim Luani, Jan Smid, Marc Henning Schäfer, Jens Schreiber, Ivan Tanev, Fabian Wengler, Naira Beniki Yeritsyan, Paul Steendijk, Ruediger C Braun-Dullaeus
BACKGROUND: Right ventricular (RV) dysfunction is recognized as a cardinal prognostic marker in systolic heart failure patients. Conflicting data exist on the interaction of RV function and left ventricular (LV) reverse remodeling after cardiac resynchronization therapy (CRT). This prospective monocentric trial was set up to assess the predictive value of baseline RV function and corresponding RV-pulmonary artery (PA) coupling on LV reverse remodeling after CRT. METHODS: 110 patients with a CRT indication were prospectively enrolled...
March 8, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29546747/principles-of-hemodynamic-for-mechanical-circulatory-support-patho-physiological-key-aspects-of-assisted-pci
#6
Eloisa Basile, Giulio Russo, Antonio M Leone
It is essential to understand the pathophysiology of cardiogenic shock and the possible deterioration of contractile function during high-risk PCI in order to select those patients who could benefit from mechanical support thus choosing the most suitable device in every situation. Percutaneous Ventricular Assist Devices (pVAD) provide hemodynamic support by improving cardiac output and mean arterial pressure, but their specific features result in different hemodynamic effects and degrees of myocardial ischemic protection and LV unloading...
March 15, 2018: Minerva Cardioangiologica
https://www.readbyqxmd.com/read/29545259/distinct-hemodynamic-changes-after-interventional-mitral-valve-edge-to-edge-repair-in-different-phenotypes-of-heart-failure-an-integrated-hemodynamic-analysis
#7
Benedikt Schrage, Daniel Kalbacher, Michael Schwarzl, Nicole Rübsamen, Christoph Waldeyer, Peter Moritz Becher, Eike Tigges, Daniel Burkhoff, Stefan Blankenberg, Edith Lubos, Ulrich Schäfer, Dirk Westermann
BACKGROUND: Percutaneous mitral valve edge-to-edge repair (pMVR) with a MitraClip is beneficial for the clinical symptoms of patients irrespective of the ejection fraction (EF). Nevertheless, the consequences on hemodynamics are poorly understood. Therefore, we used data from noninvasive pressure-volume loops to investigate the left ventricular (LV) remodeling of patients after pMVR dependent on their baseline EF. METHODS AND RESULTS: In 130 patients with successful pMVR, the end-diastolic pressure-volume relationship (EDPVR) and end-systolic pressure-volume relationship were estimated noninvasively from echocardiographic data...
March 15, 2018: Journal of the American Heart Association
https://www.readbyqxmd.com/read/29517515/left-ventricular-unloading-during-veno-arterial-ecmo-a-simulation-study
#8
Dirk W Donker, Daniel Brodie, José P S Henriques, Michael Broomé
Veno-arterial extracorporeal membrane oxygenation (VA ECMO) is widely used in cardiogenic shock. It provides systemic perfusion, but left ventricular (LV) unloading is suboptimal. Using a closed-loop, real-time computer model of the human cardiovascular system, cardiogenic shock supported by peripheral VA ECMO was simulated and effects of various adjunct LV unloading interventions were quantified. After VA ECMO initiation (4 L/min) in cardiogenic shock (baseline), hemodynamics improved (mean arterial pressure (MAP) increased to 85 mmHg), while LV overload occurred (10% increase in end-diastolic volume (EDV), and 5 mmHg increase in pulmonary capillary wedge pressure (PCWP))...
March 6, 2018: ASAIO Journal: a Peer-reviewed Journal of the American Society for Artificial Internal Organs
https://www.readbyqxmd.com/read/29512293/adaptation-to-acute-pulmonary-hypertension-in-pigs
#9
Mare Mechelinck, Marc Hein, Sven Bellen, Rolf Rossaint, Anna B Roehl
The extent of right ventricular compensation compared to the left ventricle is restricted and varies among individuals, which makes it difficult to define. While establishing a model of acute pulmonary hypertension in pigs we observed two different kinds of compensation in our animals. Looking deeper into the hemodynamic data we tried to delineate why some animals could compensate and others could not. Pulmonary hypertension (mean pressure 45 mmHg) was induced gradually by infusion of a stable thromboxane A2 analogue U46619 in a porcine model (n = 22)...
March 2018: Physiological Reports
https://www.readbyqxmd.com/read/29474668/real-time-left-ventricular-pressure-volume-loops-during-percutaneous-central-arteriovenous-anastomosis
#10
Sebastian Ewen, Lucas Lauder, Michael Böhm, Felix Mahfoud
No abstract text is available yet for this article.
February 20, 2018: European Heart Journal
https://www.readbyqxmd.com/read/29449367/load-independent-systolic-and-diastolic-right-ventricular-function-in-heart-failure-with-preserved-ejection-fraction-as-assessed-by-resting-and-handgrip-exercise-pressure-volume-loops
#11
Karl-Philipp Rommel, Maximilian von Roeder, Christian Oberueck, Konrad Latuscynski, Christian Besler, Stephan Blazek, Thomas Stiermaier, Karl Fengler, Volker Adams, Marcus Sandri, Axel Linke, Gerhard Schuler, Holger Thiele, Philipp Lurz
BACKGROUND: Although systolic right ventricular (RV) dysfunction has been shown to be a potent predictor for adverse outcomes in patients with heart failure with preserved ejection fraction (HFpEF), RV functional abnormalities in the course of the syndrome are not well characterized. We, therefore, sought to assess load-independent and load-dependent systolic and diastolic characteristics of RV function in stable outpatients with HFpEF. METHODS AND RESULTS: We invasively obtained RV and left ventricular pressure-volume loops in 24 HFpEF patients and 9 patients without heart failure symptoms with a conductance catheter during basal conditions and handgrip exercise...
February 2018: Circulation. Heart Failure
https://www.readbyqxmd.com/read/29437172/closed-loop-feedback-control-for-microfluidic-systems-through-automated-capacitive-fluid-height-sensing
#12
L R Soenksen, T Kassis, M Noh, L G Griffith, D L Trumper
Precise fluid height sensing in open-channel microfluidics has long been a desirable feature for a wide range of applications. However, performing accurate measurements of the fluid level in small-scale reservoirs (<1 mL) has proven to be an elusive goal, especially if direct fluid-sensor contact needs to be avoided. In particular, gravity-driven systems used in several microfluidic applications to establish pressure gradients and impose flow remain open-loop and largely unmonitored due to these sensing limitations...
February 13, 2018: Lab on a Chip
https://www.readbyqxmd.com/read/29420355/inotropic-effects-of-nicorandil-on-cardiac-contractility-assessed-by-left-ventricular-pressure-volume-relationship-analyses-in-anesthetized-monkeys
#13
Tomomichi Ishizaka, Yu Yoshimatsu, Yu Maeda, Katsuyoshi Chiba, Kazuhiko Mori
Nicorandil is a representative antianginal drug that has dual properties of a nitrate and adenosine triphosphate-sensitive potassium (KATP) channel agonist; however, its effects on integrated cardiac function have not been fully understood. This study was conducted to clarify the functional, hemodynamic, and electrophysiological effects of nicorandil using ventricular pressure-volume loop analysis in isoflurane-anesthetized monkeys. Nicorandil was given intravenously at therapeutic doses of 0.2 and 2 mg/kg over 10 minutes to cynomolgus monkeys (n = 5) with a pause of 10 minutes between the 2 doses...
February 2018: Journal of Cardiovascular Pharmacology
https://www.readbyqxmd.com/read/29411336/central-sleep-apnea-with-cheyne-stokes-breathing-in-heart-failure-from-research-to-clinical-practice-and-beyond
#14
K Terziyski, A Draganova
Characterized by periodic crescendo-decrescendo pattern of breathing alternating with central apneas, Central sleep apnea (CSA) with Cheyne-Stokes Breathing represents a highly prevalent, yet underdiagnosed comorbidity in chronic heart failure (CHF). A diverse body of evidence demonstrates increased morbidity and mortality in the presence of CSB. CSB has been described in both CHF patients with preserved and reduced ejection fraction, regardless of drug treatment. Risk factors for CSB are older age, male gender, high BMI, atrial fibrillation and hypocapnia...
February 7, 2018: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/29400533/anomalous-features-in-the-potential-energy-landscape-of-a-waterlike-monatomic-model-with-liquid-and-glass-polymorphism
#15
Gang Sun, Limei Xu, Nicolas Giovambattista
We study the potential energy landscape (PEL) of a waterlike monatomic liquid that exhibits a liquid-liquid phase transition (LLPT) and glass-glass transformation (GGT). We identify two anomalous features of the PEL that give origin to both phenomena. Specifically, during the pressure-induced LLPT and GGT, (i) the inherent structures (IS) energy becomes a concave function of volume, and (ii) the IS pressure exhibits a van der Waals-like loop. We argue that features (i) and (ii) imply that the GGT is a (nonequilibrium) first-order phase transition, analogous to the LLPT...
January 19, 2018: Physical Review Letters
https://www.readbyqxmd.com/read/29394944/windkessel-model-of-hemodynamic-state-supported-by-a-pulsatile-ventricular-assist-device-in-premature-ventricle-contraction
#16
Keun Her, Joon Yeong Kim, Ki Moo Lim, Seong Wook Choi
BACKGROUND: Counter-pulsation control (CPC) by ventricular assist devices (VADs) is believed to reduce cardiac load and increase coronary perfusion. However, patients with VADs have a higher risk of arrhythmia, which may cause the CPC to fail. Consequently, CPC has not been applied by VADs in clinical practice. The phase-locked loop (PLL) algorithm for CPC is readily implemented in VADs; however, it requires a normal, consistent heartbeat for adequate performance. When an arrhythmia occurs, the algorithm maintains a constant pumping rate despite the unstable heartbeat...
February 2, 2018: Biomedical Engineering Online
https://www.readbyqxmd.com/read/29365118/initial-in-vitro-testing-of-a-paediatric-continuous-flow-total-artificial-heart
#17
Kiyotaka Fukamachi, Jamshid H Karimov, David J Horvath, Gengo Sunagawa, Nicole A Byram, Barry D Kuban, Nader Moazami
OBJECTIVES: Mechanical circulatory support has become standard therapy for adult patients with end-stage heart failure; however, in paediatric patients with congenital heart disease, the options for chronic mechanical circulatory support are limited to paracorporeal devices or off-label use of devices intended for implantation in adults. Congenital heart disease and cardiomyopathy often involve both the left and right ventricles; in such cases, heart transplantation, a biventricular assist device or a total artificial heart is needed to adequately sustain both pulmonary and systemic circulations...
January 19, 2018: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/29350681/aav-9-mediated-phosphatase-1-inhibitor-1-overexpression-improves-cardiac-contractility-in-unchallenged-mice-but-is-deleterious-in-pressure-overload
#18
D M Schwab, L Tilemann, R Bauer, M Heckmann, A Jungmann, M Wagner, J Burgis, C Vettel, H A Katus, A El-Armouche, O J Müller
The downregulation of β-adrenergic receptors (β-AR) and decreased cAMP-dependent protein kinase activity in failing hearts results in decreased phosphorylation and inactivation of phosphatase-inhibitor-1 (I-1), a distal amplifier element of β-adrenergic signaling, leading to increased protein phosphatase 1 activity and dephosphorylation of key phosphoproteins, including phospholamban. Downregulated and hypophosphorylated I-1 likely contributes to β-AR desensitization; therefore its modulation is a promising approach in heart failure treatment...
January 2018: Gene Therapy
https://www.readbyqxmd.com/read/29330837/computer-simulated-modeling-of-healthy-and-diseased-right-ventricular-and-pulmonary-circulation
#19
Jody Chou, Joseph B Rinehart
We have previously developed a simulated cardiovascular physiology model for in-silico testing and validation of novel closed-loop controllers. To date, a detailed model of the right heart and pulmonary circulation was not needed, as previous controllers were not intended for use in patients with cardiac or pulmonary pathology. With new development of controllers for vasopressors, and looking forward, for combined vasopressor-fluid controllers, modeling of right-sided and pulmonary pathology is now relevant to further in-silico validation, so we aimed to expand our existing simulation platform to include these elements...
January 12, 2018: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/29310997/neurohormonal-imbalance-a-neglected-problem-and-potential-therapeutic-target-in-acute-heart-failure
#20
Steven R Goldsmith, Bradley A Bart, Ileana L Pin A
Decompensated or acute heart failure (AHF) is characterized by increased ventricular and atrial pressures which may lead to and be caused by circulatory congestion. Unless due to a primary decrease in cardiac function, congestion arises from volume expansion or vasoconstriction. In turn, volume expansion and vasoconstriction are due to neurohormonal imbalance since both result from activation of the sympathetic nervous system, the renin-angiotensin-aldosterone axis and excess secretion of arginine vasopressin...
December 16, 2017: Current Problems in Cardiology
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