Helium-oxygen reduces the production of carbon dioxide during weaning from mechanical ventilation

<p>Abstract</p> <p>Background</p> <p>Prolonged weaning from mechanical ventilation has a major impact on ICU bed occupancy and patient outcome, and has significant cost implications.</p> <p>There is evidence in patients around the period of extubation that helium-oxygen leads to a reduction in the work of breathing. Therefore breathing helium-oxygen during weaning may be a useful adjunct to facilitate weaning. We hypothesised that breathing helium-oxygen would reduce carbon dioxide production during the weaning phase of mechanical ventilation.</p> <p>Materials/patients and methods</p> <p>We performed a prospective randomised controlled single blinded cross-over trial on 19 adult intensive care patients without significant airways disease who fulfilled criteria for weaning with CPAP. Patients were randomised to helium-oxygen and air-oxygen delivered during a 2 hour period of CPAP ventilation. Carbon dioxide production (VCO₂) was measured using a near patient main stream infrared carbon dioxide sensor and fixed orifice pneumotachograph.</p> <p>Results</p> <p>Compared to air-oxygen, helium-oxygen significantly decreased VCO₂production at the end of the 2 hour period of CPAP ventilation; there was a mean difference in CO₂production of 48.9 ml/min (95% CI 18.7-79.2 p = 0.003) between the groups. There were no significant differences in other respiratory and haemodynamic parameters.</p> <p>Conclusion</p> <p>This study shows that breathing a helium-oxygen mixture during weaning reduces carbon dioxide production. This physiological study supports the need for a clinical trial of helium-oxygen mixture during the weaning phase of mechanical ventilation with duration of weaning as the primary outcome.</p> <p>Trial registration</p> <p>ISRCTN56470948</p

Ground-based FTIR measurements of O3- and climate-related gases in the free troposphere and lower stratosphere

In the frame of the EC project UFTIR (Time series of Upper Free Troposphere observations from a European ground-based FTIR network), a common strategy for an optimal determination of the chemical composition in the free troposphere and lower stratosphere with ground-based Fourier-transform infrared (FTIR) spectrometers is being developed. The project focuses on 6 target species that are O3, CO, CH4, N2O, C2H6 and CHClF2 (HCFC-22). The strategy consists in selecting the most appropriate parameters to retrieve vertical concentration profiles from solar FTIR spectra. Among the important parameters are the spectral microwindows: they have been optimised to maximise the information content and to minimize the influence of poorly known spectroscopic data and interfering species

Divided Loyalists or Conditional Cooperators? Creating Consensus about Cooperation in Multiple Simultaneous Social Dilemmas

The current social dilemma literature lacks theoretical consensus regarding how individuals behave when facing multiple simultaneous social dilemmas. The divided-loyalty hypothesis, from organizational theory, predicts that cooperation will decline as individuals experience multiple social dilemmas with different compared to the same group members. The conditional-cooperation hypothesis, from behavioral economics, predicts that cooperation will increase as individuals experience multiple social dilemmas with different compared to the same group members. We employ a laboratory experiment to create consensus between these literatures and find support for the conditional-cooperation hypothesis. The positive effect of interacting with different group members comes from participants having an opportunity to shift their cooperative behavior from the less cooperative to the more cooperative group

Assessing uncertainty associated with the monitoring and evaluation of spatially managed areas

Marine spatial planning (MSP) is advocated to support an ecosystem approach to marine management, as it allows consideration of multiple management objectives including marine conservation. The monitoring and evaluation of both implemented marine plans and the planning process itself is susceptible to various uncertainties. Here, uncertainties related to a stepwise monitoring and evaluation framework for spatially managed areas were characterised and quantified with the help of two modified and developed tools. In particular, Walker-type and pedigree matrices were utilised to assess both the sources and respective relative levels of uncertainty present in the assessment of nine European case studies that conducted a stepwise monitoring and evaluation process applying a common framework. Across the southern and northern European case studies major sources of uncertainty were found in relation to the knowledge base, management scenarios with related objectives and data availability. Although case studies made flexible use of the framework to account for the particularities of the local realms, the revealed pattern of associated uncertainty was highly consistent across the case studies. The scored pedigree matrices showed that the criteria ‘stakeholder engagement’ and ‘cross validation’ had greatest influence on the overall robustness of the case study assessments. The observed distribution of median pedigree scores was within acceptable ranges with respect to simulated possible score distributions. In addition, a sensitivity analysis revealed that the scoring of the pedigree criteria by five or more experts would result in less variable interquartile ranges of respective median scores. In conclusion, the developed complementary tools showed great flexibility in characterising and assessing uncertainty despite context-dependent differences among case studies such as geographical area, quality of available data, level of spatial management implementation or management objectives. Moreover, the obtained findings allow prioritising efforts and future research to support an iterative monitoring and evaluation of marine spatial plans

Assessing uncertainty associated with the monitoring and evaluation of spatially managed areas

Marine spatial planning (MSP) is advocated to support an ecosystem approach to marine management, as it allows consideration of multiple management objectives including marine conservation. The monitoring and evaluation of both implemented marine plans and the planning process itself is susceptible to various uncertainties. Here, uncertainties related to a stepwise monitoring and evaluation framework for spatially managed areas were characterised and quantified with the help of two modified and developed tools. In particular, Walker-type and pedigree matrices were utilised to assess both the sources and respective relative levels of uncertainty present in the assessment of nine European case studies that conducted a stepwise monitoring and evaluation process applying a common framework. Across the southern and northern European case studies major sources of uncertainty were found in relation to the knowledge base, management scenarios with related objectives and data availability. Although case studies made flexible use of the framework to account for the particularities of the local realms, the revealed pattern of associated uncertainty was highly consistent across the case studies. The scored pedigree matrices showed that the criteria ‘stakeholder engagement’ and ‘cross validation’ had greatest influence on the overall robustness of the case study assessments. The observed distribution of median pedigree scores was within acceptable ranges with respect to simulated possible score distributions. In addition, a sensitivity analysis revealed that the scoring of the pedigree criteria by five or more experts would result in less variable interquartile ranges of respective median scores. In conclusion, the developed complementary tools showed great flexibility in characterising and assessing uncertainty despite context-dependent differences among case studies such as geographical area, quality of available data, level of spatial management implementation or management objectives. Moreover, the obtained findings allow prioritising efforts and future research to support an iterative monitoring and evaluation of marine spatial plans

Publishing in the academy of management journals

Perhaps you are a doctoral student, mapping out how to parcel your dissertation; perhaps you are a junior scholar, strategizing your research plan; perhaps you are a senior scholar, who is thinking about what you want to say to the field. No matter what stage you are at as a management researcher, you might be looking to the Academy of Management (AOM) journals as a natural home for any and all of these creative research pursuits. However, it might not always be crystal clear how you should craft your work for the AOM journals, what contribution you might make at each journal, and consequently to which journal you should target your intellectual contributions

Publishing in the academy of management journals

Perhaps you are a doctoral student, mapping out how to parcel your dissertation; perhaps you are a junior scholar, strategizing your research plan; perhaps you are a senior scholar, who is thinking about what you want to say to the field. No matter what stage you are at as a management researcher, you might be looking to the Academy of Management (AOM) journals as a natural home for any and all of these creative research pursuits. However, it might not always be crystal clear how you should craft your work for the AOM journals, what contribution you might make at each journal, and consequently to which journal you should target your intellectual contributions

Publishing in the academy of management journals

Perhaps you are a doctoral student, mapping out how to parcel your dissertation; perhaps you are a junior scholar, strategizing your research plan; perhaps you are a senior scholar, who is thinking about what you want to say to the field. No matter what stage you are at as a management researcher, you might be looking to the Academy of Management (AOM) journals as a natural home for any and all of these creative research pursuits. However, it might not always be crystal clear how you should craft your work for the AOM journals, what contribution you might make at each journal, and consequently to which journal you should target your intellectual contributions