203 research outputs found
DNS of the interaction between a shock wave and a turbulent shear flow
No full textDirect numerical simulation is used to study the interaction of a Mach 1.5 shock wave and various types of anisotropic turbulent flows. We compare the interaction of isotropic, axisymmetric and sheared turbulences (sometimes combined), with a specific interest for the sheared situation
DNS of the interaction between a shock wave and a turbulent shear flow: some effects of anisotropy
No full textDirect numerical simulation is used to study the interaction of a Mach 1.5 shock wave and various types of anisotropic turbulent flows. We compare the interaction of isotropic, axisymmetric and sheared turbulences (sometimes combined), with a specific interest for the sheared situation. The sign and magnitude of the correlation between the velocity and temperature fluctuations are found to have a crucial influence on the kinetic energy amplification across the shock. A decrease in magnitude is observed during the interaction for the velocity cross-correlation. The balance equation of this quantity is investigated and the terms responsible for this behaviour are identified. The shear stress effect upon fluctuating vorticity and the dissipation length scale is also presented. Thermodynamic fluctuations are finally analyzed, showing the departure from the isentropic state in the sheared situation compared to the isotropic one
sj-docx-1-cjk-10.1177_20543581221145073 – Supplemental material for Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients
No full textSupplemental material, sj-docx-1-cjk-10.1177_20543581221145073 for Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients by Antoine Marchiset, Valerie Serazin, Omar Ben Hadj Salem, Claire Pichereau, Lionel Lima Da Silva, Siu-Ming Au, Christophe Barbier, Yann Loubieres, Jan Hayon, Julia Gross, Herve Outin and Matthieu Jamme in Canadian Journal of Kidney Health and Disease</p
sj-docx-2-cjk-10.1177_20543581221145073 – Supplemental material for Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients
No full textSupplemental material, sj-docx-2-cjk-10.1177_20543581221145073 for Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients by Antoine Marchiset, Valerie Serazin, Omar Ben Hadj Salem, Claire Pichereau, Lionel Lima Da Silva, Siu-Ming Au, Christophe Barbier, Yann Loubieres, Jan Hayon, Julia Gross, Herve Outin and Matthieu Jamme in Canadian Journal of Kidney Health and Disease</p
sj-jpg-4-cjk-10.1177_20543581221145073 – Supplemental material for Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients
No full textSupplemental material, sj-jpg-4-cjk-10.1177_20543581221145073 for Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients by Antoine Marchiset, Valerie Serazin, Omar Ben Hadj Salem, Claire Pichereau, Lionel Lima Da Silva, Siu-Ming Au, Christophe Barbier, Yann Loubieres, Jan Hayon, Julia Gross, Herve Outin and Matthieu Jamme in Canadian Journal of Kidney Health and Disease</p
sj-docx-3-cjk-10.1177_20543581221145073 – Supplemental material for Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients
No full textSupplemental material, sj-docx-3-cjk-10.1177_20543581221145073 for Risk Factors of AKI in Acute Respiratory Distress Syndrome: A Time-Dependent Competing Risk Analysis on Severe COVID-19 Patients by Antoine Marchiset, Valerie Serazin, Omar Ben Hadj Salem, Claire Pichereau, Lionel Lima Da Silva, Siu-Ming Au, Christophe Barbier, Yann Loubieres, Jan Hayon, Julia Gross, Herve Outin and Matthieu Jamme in Canadian Journal of Kidney Health and Disease</p
A study of sheared turbulence/shock interaction: velocity fluctuations and enstrophy behaviour
No full textDirect Numerical Simulations of the idealized interaction of a normal shock wave with several turbulent shear flows are conducted. We analyse the behaviours of velocity and vorticity fluctuations and compare them to what happens in the isotropic situation. Investigation of the budgets of these quantities allows to isolate the mechanisms underlying the physics of the interaction, and reveals the importance of enthalpic production and baroclinic torque in such flows
Insuffisance rénale aiguë en réanimation : facteurs de risque d'origine iatrogène et devenir à long terme
No full textAcute kidney injury (AKI) is a common complication observed in half of intensive care unit patients. Associated with a poor short-term outcome, AKI seems to be associated with an increased risk of chronic kidney disease (CKD) in survivors. Due to the diversity of pathophysiological processes involved in the development of AKI and the identification of risk factors that are mostly inaccessible to human intervention, the therapeutic management of AKI remains limited.The aim of this study is twofold: (1) to confirm the long-term impact of AKI and (2) to identify iatrogenic risk factors potentially involved in the development of AKI.We analysed several databases composed of ICU patients and used statistical methods adapted to the longitudinal format and the competition situation.We identified AKI as an independent factor in the occurrence of CKD. Among the risk factors analysed, we found an impact of invasive mechanical ventilation via positive end-expiratory pressure, central venous pressure and hypercapnia on the risk of developing AKI. We observed that trajectories of chloremia, in particular increasing ones, were more associated with AKI. We reported for the first time the negative renal impact of amoxicillin urinary crystal.In total, our work has confirmed the long-term renal impact of AKI, including in patients who recover their renal function at discharge. Among the therapeutic interventions performed in the ICU: mechanical ventilation, changes in blood chloride levels and the use of high-dose antibiotics seem to increase the risk of renal failure.L'insuffisance rénale aiguë (IRA) est une complication observée chez 50% des patients admis en réanimation. Impactant fortement le pronostic à court terme, l'IRA semble aussi associé à un sur risque de maladie rénale chronique (MRC). Du fait de l'importante diversité des processus physiopathologiques impliqués dans le développement de l'IRA et l'identification de facteur de risque majoritairement non accessibles à une intervention humaine, la gestion thérapeutique de l'IRA reste à ce jour limitée.L'objectif de ce travail est double : (1) confirmer l'impact à long terme de l'IRA et (2) identifier des facteurs de risque iatrogène potentiellement impliqué dans le développement de l'IRA. Pour cela, plusieurs bases de données composées essentiellement de patients admis en unité de soins critiques ont été analysée à partir de méthodes statistiques adaptées au format longitudinal de certaines covariables et à la situation de compétition.Nous avons identifié que l'IRA est un facteur indépendant de survenue de MRC. Parmi les facteurs de risque analysés, nous avons mis en évidence un impact de la ventilation mécanique invasive via la pression expiratoire positive, la pression veineuse centrale et l'hypercapnie sur le risque de développer une IRA. Nous avons observé que certaines trajectoires de chlorémie, en particulier celles croissantes étaient plus associées à l'IRA. Nous avons rapporté pour la 1ère fois l'impact négatif au niveau rénal de la formation de critaux d'amoxicilline.Au total, notre travail a permi de confirmer l'impact renal à long terme de l'IRA y compris chez les patients récupérant ad integrum une fonction rénale. Parmi les interventions thérapeutiques réalisées en réanimation : la ventilation mécanique, les modifications de chlorémie et l'utilisation de forte dose d'antibiotiques semblent majorer le risque de défaillance rénale
Acute kidney injury in intensive care unit : Iatrogenic risk factors and long-term prognosis
No full textL'insuffisance rénale aiguë (IRA) est une complication observée chez 50% des patients admis en réanimation. Impactant fortement le pronostic à court terme, l'IRA semble aussi associé à un sur risque de maladie rénale chronique (MRC). Du fait de l'importante diversité des processus physiopathologiques impliqués dans le développement de l'IRA et l'identification de facteur de risque majoritairement non accessibles à une intervention humaine, la gestion thérapeutique de l'IRA reste à ce jour limitée.L'objectif de ce travail est double : (1) confirmer l'impact à long terme de l'IRA et (2) identifier des facteurs de risque iatrogène potentiellement impliqué dans le développement de l'IRA. Pour cela, plusieurs bases de données composées essentiellement de patients admis en unité de soins critiques ont été analysée à partir de méthodes statistiques adaptées au format longitudinal de certaines covariables et à la situation de compétition.Nous avons identifié que l'IRA est un facteur indépendant de survenue de MRC. Parmi les facteurs de risque analysés, nous avons mis en évidence un impact de la ventilation mécanique invasive via la pression expiratoire positive, la pression veineuse centrale et l'hypercapnie sur le risque de développer une IRA. Nous avons observé que certaines trajectoires de chlorémie, en particulier celles croissantes étaient plus associées à l'IRA. Nous avons rapporté pour la 1ère fois l'impact négatif au niveau rénal de la formation de critaux d'amoxicilline.Au total, notre travail a permi de confirmer l'impact renal à long terme de l'IRA y compris chez les patients récupérant ad integrum une fonction rénale. Parmi les interventions thérapeutiques réalisées en réanimation : la ventilation mécanique, les modifications de chlorémie et l'utilisation de forte dose d'antibiotiques semblent majorer le risque de défaillance rénale.Acute kidney injury (AKI) is a common complication observed in half of intensive care unit patients. Associated with a poor short-term outcome, AKI seems to be associated with an increased risk of chronic kidney disease (CKD) in survivors. Due to the diversity of pathophysiological processes involved in the development of AKI and the identification of risk factors that are mostly inaccessible to human intervention, the therapeutic management of AKI remains limited.The aim of this study is twofold: (1) to confirm the long-term impact of AKI and (2) to identify iatrogenic risk factors potentially involved in the development of AKI.We analysed several databases composed of ICU patients and used statistical methods adapted to the longitudinal format and the competition situation.We identified AKI as an independent factor in the occurrence of CKD. Among the risk factors analysed, we found an impact of invasive mechanical ventilation via positive end-expiratory pressure, central venous pressure and hypercapnia on the risk of developing AKI. We observed that trajectories of chloremia, in particular increasing ones, were more associated with AKI. We reported for the first time the negative renal impact of amoxicillin urinary crystal.In total, our work has confirmed the long-term renal impact of AKI, including in patients who recover their renal function at discharge. Among the therapeutic interventions performed in the ICU: mechanical ventilation, changes in blood chloride levels and the use of high-dose antibiotics seem to increase the risk of renal failure
Erratum to: Multiple imputation is better than KDIGO guidelines for estimating unknown baseline renal function
No full text- …
