BackgroundInsertion of a central venous catheter (CVC) is common practice in critical care medicine. Complications arising from CVC placement are mostly due to a pneumothorax or malposition. Correct position is currently confirmed by chest x-ray, while ultrasonography might be a more suitable option. We performed a meta-analysis of the available studies with the primary aim of synthesizing information regarding detection of CVC-related complications and misplacement using ultrasound (US).MethodsThis is a systematic review and meta-analysis registered at PROSPERO (CRD42016050698). PubMed, EMBASE, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were searched. Articles which reported the diagnostic accuracy of US in detecting the position of CVCs and the mechanical complications associated with insertion were included. Primary outcomes were specificity and sensitivity of US. Secondary outcomes included prevalence of malposition and pneumothorax, feasibility of US examination, and time to perform and interpret both US and chest x-ray. A qualitative assessment was performed using the QUADAS-2 tool.ResultsWe included 25 studies with a total of 2548 patients and 2602 CVC placements. Analysis yielded a pooled specificity of 98.9 (95% confidence interval (CI): 97.8–99.5) and sensitivity of 68.2 (95% CI: 54.4–79.4). US examination was feasible in 96.8% of the cases. The prevalence of CVC malposition and pneumothorax was 6.8% and 1.1%, respectively. The mean time for US performance was 2.83 min (95% CI: 2.77–2.89 min) min, while chest x-ray performance took 34.7 min (95% CI: 32.6–36.7 min). US was feasible in 97%. Further analyses were performed by defining subgroups based on the different utilized US protocols and on intra-atrial and extra-atrial misplacement. Vascular US combined with transthoracic echocardiography was most accurate.ConclusionsUS is an accurate and feasible diagnostic modality to detect CVC malposition and iatrogenic pneumothorax. Advantages of US over chest x-ray are that it can be performed faster and does not subject patients to radiation. Vascular US combined with transthoracic echocardiography is advised. However, the results need to be interpreted with caution since included studies were often underpowered and had methodological limitations. A large multicenter study investigating optimal US protocol, among other things, is needed.Electronic supplementary materialThe online version of this article (10.1186/s13054-018-1989-x) contains supplementary material, which is available to authorized users.
Background Diaphragm ultrasonography is rapidly evolving in both critical care and research. Nevertheless, methodologically robust guidelines on its methodology and acquiring expertise do not, or only partially, exist. Therefore, we set out to provide consensus-based statements towards a universal measurement protocol for diaphragm ultrasonography and establish key areas for research. Methods To formulate a robust expert consensus statement, between November 2020 and May 2021, a two-round, anonymous and online survey-based Delphi study among experts in the field was performed. Based on the literature review, the following domains were chosen: “Anatomy and physiology”, “Transducer Settings”, “Ventilator Impact”, “Learning and expertise”, “Daily practice” and “Future directions”. Agreement of ≥ 68% (≥ 10 panelists) was needed to reach consensus on a question. Results Of 18 panelists invited, 14 agreed to participate in the survey. After two rounds, the survey included 117 questions of which 42 questions were designed to collect arguments and opinions and 75 questions aimed at reaching consensus. Of these, 46 (61%) consensus was reached. In both rounds, the response rate was 100%. Among others, there was agreement on measuring thickness between the pleura and peritoneum, using > 10% decrease in thickness as cut-off for atrophy and using 40 examinations as minimum training to use diaphragm ultrasonography in clinical practice. In addition, key areas for research were established. Conclusion This expert consensus statement presents the first set of consensus-based statements on diaphragm ultrasonography methodology. They serve to ensure high-quality and homogenous measurements in daily clinical practice and in research. In addition, important gaps in current knowledge and thereby key areas for research are established. Trial registration The study was pre-registered on the Open Science Framework with registration digital object identifier https://doi.org/10.17605/OSF.IO/HM8UG.
OBJECTIVES This study was designed to assess the prognostic value of a new comprehensive coronary computed tomography angiography (CTA) score compared with the stenosis severity component of the Coronary Artery Disease-Reporting and Data System (CAD-RADS).BACKGROUND Current risk assessment with coronary CTA is mainly focused on maximal stenosis severity.Integration of plaque extent, location, and composition in a comprehensive model may improve risk stratification.METHODS A total of 2,134 patients with suspected but without known CAD were included. The predictive value of the comprehensive CTA score (ranging from 0 to 42 and divided into 3 groups: 0 to 5, 6 to 20, and >20) was compared with the CAD-RADS combined into 3 groups (0% to 30%, 30% to 70% and $70% stenosis). Its predictive performance was internally and externally validated (using the 5-year follow-up dataset of the CONFIRM [Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter Registry] registry, n ¼ 1,971). RESULTSPatients mean age was 55 AE 13 years, mean follow-up 3.6 AE 2.8 years, and 130 events (myocardial infarction or death) occurred. The new, comprehensive CTA score showed strong and independent predictive value using the Cox proportional hazard analysis. A model including clinical variables plus comprehensive CTA score showed better discrimination of events compared with a model consisting of clinical variables plus CAD-RADS (0.768 vs. 0.742, p ¼ 0.001). Also, the comprehensive CTA score correctly reclassified a significant proportion of patients compared with the CAD-RADS (net reclassification improvement 12.4%, p < 0.001). Good predictive accuracy was reproduced in the external validation cohort.CONCLUSIONS The new comprehensive CTA score provides better discrimination and reclassification of events compared with the CAD-RADS score based on stenosis severity only. The score retained similar prognostic accuracy when externally validated. Anatomic risk scores can be improved with the addition of extent, location, and compositional measures of atherosclerotic plaque. Comprehensive CTA risk score calculator is available at:
The development of structure -property relationships are described for new commercial grade internal olefin sulfonates (marketed as the ENORDET TM O series) and laboratory scale alcohol-alkoxy-sulfate surfactants for use in chemical flooding. Surfactant structure was characterised by an in-house developed liquid chromatography mass spectrometry (LC-MS) technique and properties focused on oil/water microemulsion phase behaviour. Such relationships are important to match the surfactant formulation to particular reservoir conditions (temperature, salinity and crude oil). The relationship between IOS structure (by LC-MS) and optimal salinity (by phase tests) has been modeled by the empirical HLB number and by a semi-empirical molecular model. An IOS 24-28 based surfactant system gave excellent microemulsion performance with several, regionally different crude oils and an initial correlation of performance with the composition crude oils has been made. The IOS surfactants described have been produced on a pilot scale and with consistent quality. This commercially available family, and the commercially available alcohol-alkoxy-sulfate family, cover most of the salinity and temperature reservoir conditions expected, though for high temperature and high salinity reservoirs, alcohol based sulfonates will most likely be required. Finally, the chemistry of production of the IOS surfactants and their handling properties are summarised. Part 2 of this paper (SPE-129769-PP) describes work to formulate an IOS mixture that was subsequently used in a successful ASP field test. SPE 129766There is a body of work that describes the testing protocols and properties required to screen suitable EOR surfactants 6, 8, 9 . Reference 6 is also an excellent recent review of the surfactant EOR literature. Through the well-established relationship between the microemulsion phase behaviour and IFT it is common in the industry to screen surfactants and their formulations for low IFT through laboratory-based oil / water phase behaviour tests 8, 9 .The current paper will describe microemulsion phase behaviour for the IOS family and several alcohol-alkoxy-sulfates and discuss structure-property correlations to allow selection of surfactant(s) for specific reservoir conditions. It will also cover the chemistry of the manufacturing processes of the surfactants and the handling and flow properties of the surfactants produced. Chemistry and production of IOS surfactantsThe process chemistry and resulting products from reaction of high molecular weight internal olefins with SO 3 was first studied in Shell's laboratories in the 1990s, this work being part of a program to identify potential new detergent molecules 10,11 . The knowledge gained during that period has been of great help to identify the optimum process conditions to make IOS products for surfactant EOR application. IOS products have been produced based on four Internal Olefin (IO) carbon cuts, with nominal ranges C15-18, C19-23, C20-24 and C24-28.The production of an IOS consists of three ...
Background-Epicardial adipose tissue located close to the atrial wall can change the electric conduction of the left atrium, potentially leading to atrial fibrillation (AF). The aim of this study was to assess whether an increased atrial adipose tissue mass posterior to the left atrium is related to AF independent of demographical and cardiovascular risk factors.
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