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A prospective international observational prevalence study on prone positioning of ARDS patients: the APRONET (ARDS Prone Position Network) study
IntroductionWhile prone positioning (PP) has been shown to improve patient survival in moderate to severe acute respiratory distress syndrome (ARDS) patients, the rate of application of PP in clinical practice still appears low.AimThis study aimed to determine the prevalence of use of PP in ARDS patients (primary endpoint), the physiological effects of PP, and the reasons for not using it (secondary endpoints).MethodsThe APRONET study was a prospective international 1-day prevalence study performed four times in April, July, and October 2016 and January 2017. On each study day, investigators in each ICU had to screen every patient. For patients with ARDS, use of PP, gas exchange, ventilator settings and plateau pressure (Pplat) were recorded before and at the end of the PP session. Complications of PP and reasons for not using PP were also documented. Values are presented as median (1st–3rd quartiles).ResultsOver the study period, 6723 patients were screened in 141 ICUs from 20 countries (77% of the ICUs were European), of whom 735 had ARDS and were analyzed. Overall 101 ARDS patients had at least one session of PP (13.7%), with no differences among the 4 study days. The rate of PP use was 5.9% (11/187), 10.3% (41/399) and 32.9% (49/149) in mild, moderate and severe ARDS, respectively (P = 0.0001). The duration of the first PP session was 18 (16–23) hours. Measured with the patient in the supine position before and at the end of the first PP session, PaO2/FIO2 increased from 101 (76–136) to 171 (118–220) mmHg (P = 0.0001) driving pressure decreased from 14 [11–17] to 13 [10–16] cmH2O (P = 0.001), and Pplat decreased from 26 [23–29] to 25 [23–28] cmH2O (P = 0.04). The most prevalent reason for not using PP (64.3%) was that hypoxemia was not considered sufficiently severe. Complications were reported in 12 patients (11.9%) in whom PP was used (pressure sores in five, hypoxemia in two, endotracheal tube-related in two ocular in two, and a transient increase in intracranial pressure in one).ConclusionsIn conclusion, this prospective international prevalence study found that PP was used in 32.9% of patients with severe ARDS, and was associated with low complication rates, significant increase in oxygenation and a significant decrease in driving pressure.
Journal Article
Research on Position Error Prediction and Compensation of Direct Drive Turntable Based on WOABP Network
A method to identify the position error of direct drive numerical control turntable by measuring current and eccentric load is proposed, and the position error model of direct drive numerical control turntable based on whale Optimized BP (WOABP) neural network is established. The test-bed is built to measure the current, eccentric load and position error. The measured current and eccentric load are trained by WOABP neural network, and the position error of direct drive numerical control turntable is obtained. By comparing the original error, the error obtained by BP neural network and the error obtained by WOABP neural network, the effectiveness of WOABP neural network model is verified. The position error of direct drive numerical control turntable is compensated by the error obtained by the model.
Journal Article
Variety of General Position Problems in Graphs
Let X be a vertex subset of a graph G . Then$$u, vın V(G)$$u , v ∈ V ( G ) are X -positionable if$$V(P)\\cap X \\subseteq \\{u,v\\}$$V ( P ) ∩ X ⊆ u , v holds for any shortest u , v -path P . If each two vertices from X are X -positionable, then X is a general position set. The general position number of G is the cardinality of a largest general position set of G and has been already well investigated. In this paper a variety of general position problems is introduced based on which natural pairs of vertices are required to be X -positionable. This yields the total (resp. dual, outer) general position number. It is proved that the total general position sets coincide with sets of simplicial vertices, and that the outer general position sets coincide with sets of mutually maximally distant vertices. It is shown that a general position set is a dual general position set if and only if its complement is convex. Several sufficient conditions are presented that guarantee that a given graph has no dual general position set. The total general position number, the outer general position number, and the dual general position number of arbitrary Cartesian products are determined.
Journal Article
Designing alliance networks: the influence of network position, environmental change, and strategy on firm performance
Alliance networks are strategic decisions involving trade-offs between two stylized structural design choices: prominent and entrepreneurial. Prominent alliance networks emphasize benefits arising out of multiple access and affiliation to other prominent firms in the network. An entrepreneurial position, on the other hand, emphasizes brokerage and diversity benefits arising out of access to nonredundant and diverse information. We demonstrate that the performance benefits of each type of alliance network are contingent on environmental change and strategy, and are thus time dependent. Following an environmental change event in the steel industry, alliance networks that were more entrepreneurial performed better, while those that were more prominent suffered performance decline. However, when the change was radical, both types of alliance networks were negatively related to performance. We suggest that following a radical change, industry alliance networks may not have the requisite information necessary for quick and effective strategic responses. Firms pursuing an analyzer strategy performed better when emphasizing a prominent, and to a lesser extent, entrepreneurial alliance network. However, firms that develop an alliance network high on both prominent and entrepreneurial structural positions had lower relative performance. Our results indicate the need for managers to assess their alliance portfolio over time and redesign it based on environmental and strategic contingencies.
Journal Article
Combining education and income into a socioeconomic position score for use in studies of health inequalities
Background
In studies of social inequalities in health, there is no consensus on the best measure of socioeconomic position (SEP). Moreover, subjective indicators are increasingly used to measure SEP. The aim of this paper was to develop a composite score for SEP based on weighted combinations of education and income in estimating subjective SEP, and examine how this score performs in predicting inequalities in health-related quality of life (HRQoL).
Methods
We used data from a comprehensive health survey from Northern Norway, conducted in 2015/16 (
N
= 21,083). A composite SEP score was developed using adjacent-category logistic regression of subjective SEP as a function of four education and four household income levels. Weights were derived based on these indicators’ coefficients in explaining variations in respondents’ subjective SEP. The composite SEP score was further applied to predict inequalities in HRQoL, measured by the EQ-5D and a visual analogue scale.
Results
Education seemed to influence SEP the most, while income added weight primarily for the highest income category. The weights demonstrated clear non-linearities, with large jumps from the middle to the higher SEP score levels. Analyses of the composite SEP score indicated a clear social gradient in both HRQoL measures.
Conclusions
We provide new insights into the relative contribution of education and income as sources of SEP, both separately and in combination. Combining education and income into a composite SEP score produces more comprehensive estimates of the social gradient in health. A similar approach can be applied in any cohort study that includes education and income data.
Journal Article