Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42\ub74% vs 44\ub72%; absolute difference \u20131\ub769 [\u20139\ub758 to 6\ub711] p=0\ub767; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5\u20138] vs 6 [5\u20138] cm H2O; p=0\ub70011). ICU mortality was higher in MICs than in HICs (30\ub75% vs 19\ub79%; p=0\ub70004; adjusted effect 16\ub741% [95% CI 9\ub752\u201323\ub752]; p<0\ub70001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0\ub780 [95% CI 0\ub775\u20130\ub786]; p<0\ub70001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status. Funding: No funding

Noninvasive vascular occlusion with HIFU for venous insufficiency treatment: preclinical feasibility experience in rabbits

International audienceVenous insufficiency is a common disease arising when veins of the lower limb become incompetent. A conventional surgical strategy consists in stripping the incompetent veins. However, this treatment option is invasive and carries complication risks. In the present study, we propose noninvasive high-intensity focused ultrasound (HIFU) to treat lower limbs venous insufficiency, in particular incompetent perforating veins (mean diameter between 2-6 mm). Sonication parameters were designed by numerical simulations using the k-Wave toolbox to ensure continuous coagulation of a vein with a diameter superior or equal to 2 mm. The selected ultrasound exposures were 4 seconds pulses in continuous wave mode. Two types of sonication were studied: (1) fixed pulses and (2) moving pulses at constant speed (0.75 mm.s-1) across the vein. The potential of these exposures to thermally occlude veins were investigated in vivo on rabbit saphenous veins. The impact of vein compression during ultrasonic exposure was also investigated. Fifteen rabbits were used in these trials. A total of 27 saphenous veins (mean diameter 2.0 ± 0.6 mm) were sonicated with a transducer operated at 3 MHz. After a mean 15 days follow-up, rabbits were euthanized and venous samples were extracted and sent for histologic assessment. Only samples with the vein within the HIFU lesion were considered for analysis. Simulated thermal damage distribution demonstrated that fixed pulses and moving pulses respectively placed every 1.5 and 0.5 mm along the vein and delivered at an acoustic power of 85 W and for 4 seconds were able to induce continuous thermal damages along the vein segments.Experimentally, both treatment parameters (1) and (2) have proven effective to occlude veins with a success rate of 82%. Occlusion was always observed when compression was applied. Our results demonstrate that HIFU can durably and non-invasively occlude veins of diameters comparable to human veins

Buyer beware? : does the information provided with herbal products available over the counter enable safe use?

Background: Herbal products obtained over the counter are commonly used in Europe, North America and Australia. Although there is concern about a lack of information provided to consumers to allow the safe use of these products, there has been no published research to confirm these fears. In this study, we evaluated written information provided with commonly used herbal products in the UK in advance of a European Union Directive issued in April 2011 that tightened regulations for some herbal products, including requirements to provide safety information. Methods: Five commonly used herbal products were purchased from pharmacies, health food shops and supermarkets: St John’s wort, Asian ginseng, echinacea, garlic and ginkgo. Written information provided with the products (on the package or on a leaflet contained in the package) was evaluated for inclusion of each of the key safety messages included in the monographs of the US National Center for Complementary and Alternative Medicine. Specifically, we looked for information on precautions (such as Asian ginseng not being suitable for people with diabetes), interactions with conventional medicines (such as St John’s wort with the contraceptive pill and warfarin) and side effects (such as ginkgo and allergic reactions). Results: Our analysis showed that, overall, 51 (75%) of 68 products contained none of the key safety messages. This included 4 of 12 St John’s wort products, 12 of 12 ginkgo products, 6 of 7 Asian ginseng products, 20 of 21 garlic products and 9 of 13 echinacea products. The two products purchased that are registered under the new European Union regulations (for St John’s wort) contained at least 85% of the safety messages. Conclusions: Most of the herbal medicine products studied did not provide key safety information which consumers need for their safe use. The new European Union legislation should ensure that St John’s wort and echinacea products will include the previously missing information in due course. The legislation does not apply to existing stock. Depending on therapeutic claims made by manufacturers, garlic, ginkgo and Asian ginseng products may not be covered by the legislation and can continue to be bought without the safety information. Also, consumers will still be able to buy products over the internet from locations outside European Union jurisdiction. Potential purchasers need to know, in both the short term and the long term, how to purchase herbal products which provide the information they need for the safe use of these products

Rhodium-catalyzed, efficient deutero- and tritiosilylation of carbonyl compounds from hydrosilanes and deuterium or tritium

A cationic rhodium compound which is an active catalyst for both the hydrogen isotope exchange in hydrosilanes and the hydrosilylation of carbonyl compounds permits, in a one-flask, two-step procedure, efficient deutero- and tritiosilylations using SiEt3H under D2 (0.5 bar) or T2, at low catalyst loadings (0.1-0.5 mol %). © 2011 American Chemical Society.Peer Reviewe

A micromechanical model for the prediction of the lamina longitudinal compression strength of composite laminates

This paper describes a new numerical model for the prediction of the lamina longitudinal compression strength. The model assumes failure occurs by fibre microbuckling and takes into account initial fibre misalignments and matrix non-linear stress-strain behaviour. The results obtained with the 2D-base and the 3D-extended formulations agree quite well. with those of Finite Element models presented in a previous paper. Model predictions were compared with experimental data supplied by the authors' partners in a Joint Research Project. The 3D formulation proved to be the most accurate. Agreement with the experimental data is satisfactory, particularly in view of the numerous relevant variables and inevitable simplifications implicit in the models.BRITE/EURAM - BRE2-CT92-031

Modelling lamina longitudinal compression strength of carbon fibre composite laminates

The determination of the lamina longitudinal compression strength remains an unsolved problem. Non-valid failure modes are commonly observed in compression tests of unidirectional specimens. Micromechanical modelling has also proven to be a difficult task. It is believed that failure is initiated by fibre microbuckling, and that non-linear matrix behaviour and fibre misalignments play a major role. The main obstacles are thus the non-linear nature of the phenomenon and the scarcity of material data. Here 2D and 3D Finite Element models are presented. The Finite Element Method can easily deal with non-linear problems. The models are computationally inexpensive and can be easily implemented on a commercial code. A sensitivity analysis was performed using realistic input data. The model predictions are well above the unreliable experimental values so far available. Further, the most important variables were found to be the fibre misalignment angle and the matrix yield stress. The fibre spatial arrangement also affects the predicted results. Reliable strength data are essential to validate the models here presented. Nevertheless this study shows that accurate predictions should be expected to prove difficult, mainly because of the complex matrix stress-strain behaviour and the statistical nature of fibre misalignments and spatial distribution. In addition, the important role of the matrix in model results raises the question of the existence of a unique lamina longitudinal compression strength (LLCS). Lay-up dependent transverse and shear stresses acting on the load aligned laminae should accordingly yield lay-up dependent LLCSs, which is confirmed by experimental data.BRITE/EURAM - BRE2-CT92-031