Search results for "Pressure"

Research update for articles published in EJCI in 2016

2018

The association of an excessive blood pressure increase with exercise (i.e., an increase in systolic blood pressure with exercise ≥95th percentile) with lower risk of subsequent events in patients with known or suspected coronary artery disease has been consistently verified even in those with baseline hypertension. Nonetheless, this negative association, also confirmed in another study on a Japanese population, might depend on peak VO2, such that the prognostic value of blood pressure response might be limited in patients with preserved exercise capacity. In addition, a hypertensive response with exercise (defined as a systolic blood pressure ≥220 mmHg during the test) has also been associ…

Comparison of 3 ionisation methods - electron ionisation, chemical ionisation and atmospheric pressure photoionisation - for the characterisation of …

2021

International audience; Gas chromatography (GC) is a reproducible, robust, selective and sensitive method to analyse volatile organic compounds (VOCs) in a wide range of applications. The separated analytes are generally characterised by mass spectrometry (MS) under vacuum conditions. The main ionisation method is the Electron Ionisation (EI): high energy exchanges occur, causing reproducible molecular fragmentations. Chemical Ionisation (CI) is another ionisation method where a reactive gas (i.e. methane or ammonia) is ionised to form reactant ions. GC-MS can also be conducted under atmospheric pressure. Atmospheric Pressure PhotoIonisation (APPI) is the most recent source [1]. Emitted pho…

Lung density distribution in dynamic CT correlates with oxygenation in ventilated pigs with lavage ARDS † †This study contains parts of the doctoral …

2003

Background Fast dynamic computed tomography (dCT) has been used to assess regional dynamics of lung inflation and deflation processes. The aim of this study was to relate ventilation-induced changes in lung density distribution, as measured over several respiratory cycles by dCT, to oxygenation and shunt fraction in a lavage acute respiratory distress syndrome model. Methods Six anaesthetized pigs underwent pressure-constant ventilation (F I O2=1.0, inspiratory:expiratory ratio=1:1) before and after induction of lung damage by saline lavage. Mean airway pressure ( P a μ w μ ) was varied (8, 13, 18, 23, 28, 33, and 38 cm H2O) in random order. At each P a μ w μ level, dCT acquisitions were pe…

Quantification of atelectatic lung volumes in two different porcine models of ARDS.

2006

BACKGROUND: Cyclic recruitment during mechanical ventilation contributes to ventilator associated lung injury. Two different pathomechanisms in acute respiratory distress syndrome (ARDS) are currently discussed: alveolar collapse vs persistent flooding of small airways and alveoli. We compare two different ARDS animal models by computed tomography (CT) to describe different recruitment and derecruitment mechanisms at different airway pressures: (i) lavage-ARDS, favouring alveolar collapse by surfactant depletion; and (ii) oleic acid ARDS, favouring alveolar flooding by capillary leakage. METHODS: In 12 pigs [25 (1) kg], ARDS was randomly induced, either by saline lung lavage or oleic acid (…

Multirotations-CT und ARDS

2001

Purpose Aim of the study was to investigate alveolar inspiration and expiration using multiscan CT. Results of a visual assessment using a scoring system were compared with density ranges known to represent alveolar ventilation best. Method Pigs were examined before and after lavage-induced ARDS. All animals were examined using dynamic multiscan CT. The visual assessment was done by a scoring system proposed by Gattinoni. The results were compared with planimetric determination of defined density ranges. Results In the healthy lung, the visual analysis showed higher scores at lower airway pressures with a marked gradient, whereas at higher pressures neither opacities nor gradients were obse…

Do ventilatory parameters influence outcome in patients with severe acute respiratory infection? Secondary analysis of an international, multicentre1…

2021

Purpose: To investigate the possible association between ventilatory settings on the first day of invasive mechanical ventilation (IMV) and mortality in patients admitted to the intensive care unit (ICU) with severe acute respiratory infection (SARI). Materials and methods: In this pre-planned sub-study of a prospective, multicentre observational study, 441 patients with SARI who received controlled IMV during the ICU stay were included in the analysis. Results: ICU and hospital mortality rates were 23.1 and 28.1%, respectively. In multivariable analysis, tidal volume and respiratory rate on the first day of IMV were not associated with an increased risk of death; however, higher driving pr…

Mechanical ventilation parameters in critically ill COVID-19 patients: a scoping review

2021

Abstract Background The mortality of critically ill patients with COVID-19 is high, particularly among those receiving mechanical ventilation (MV). Despite the high number of patients treated worldwide, data on respiratory mechanics are currently scarce and the optimal setting of MV remains to be defined. This scoping review aims to provide an overview of available data about respiratory mechanics, gas exchange and MV settings in patients admitted to intensive care units (ICUs) for COVID-19-associated acute respiratory failure, and to identify knowledge gaps. Main text PubMed, EMBASE, and MEDLINE databases were searched from inception to October 30, 2020 for studies providing at least one v…

InBO3 and ScBO3 at high pressures: an ab initio study of elastic and thermodynamic properties

2016

We have theoretically investigated the elastic properties of calcite-type orthoborates ABO(3) (A= Sc and In) at high pressure by means of ab initio total-energy calculations. From the elastic stiffness coefficients, we have obtained the elastic moduli (B, G and E), Poisson's ratio (nu), B/G ratio, universal elastic anisotropy index (A(U)), Vickers hardness, and sound wave velocities for both orthoborates. Our simulations show that both borates are more resistive to volume compression than to shear deformation (B > G). Both compounds are ductile and become more ductile, with an increasing elastic anisotropy, as pressure increases. We have also calculated some thermodynamic properties, like D…

Abdominal Compartment Syndrome (ACS) After Surgical Abdominal Aortic Aneurysm (AAA) Repair

2009

Hypotensive Hemostasis in Patients Presenting with Ruptured Aortic Aneurysm

2017

Hypotensive hemostasis in aortic rupture has been showed to be feasible and advantageous, especially in trauma patients. To date, there are no randomized studies on hypotensive hemostasis in patients with ruptured abdominal aortic aneurysm (rAAA), but observational studies indicate similar advantages when hypotensive hemostasis is used for endovascular aneurysm repair (EVAR) as in trauma patients. Actually, in EVAR for rAAA, a target systolic blood pressure of 90 mmHg or even lower is considered safe in conscious patients. Fluids should be administrated judiciously with the sole aim of maintaining adequate cardiac output and tissue oxygenation, whereas vasoactive pressors or dilatators may …