4,070 research outputs found
Oxygen therapy in critical illness: precise control of arterial oxygenation and permissive hypoxemia
No full textObjective: the management of hypoxemia in critically ill patients is challenging. Whilst the harms of tissue hypoxia are well recognized, the possibility of harm from excess oxygen administration, or other interventions targeted at mitigating hypoxemia, may be inadequately appreciated. The benefits of attempting to fully reverse arterial hypoxemia may be outweighed by the harms associated with high concentrations of supplemental oxygen and invasive mechanical ventilation strategies. We propose two novel related strategies for the management of hypoxemia in critically ill patients. First, we describe precise control of arterial oxygenation involving the specific targeting of arterial partial pressure of oxygen or arterial hemoglobin oxygen saturation to individualized target values, with the avoidance of significant variation from these levels. The aim of precise control of arterial oxygenation is to avoid the harms associated with inadvertent hyperoxia or hypoxia through careful and precise control of arterial oxygen levels. Secondly, we describe permissive hypoxemia: the acceptance of levels of arterial oxygenation lower than is conventionally tolerated in patients. The aim of permissive hypoxemia is to minimize the possible harms caused by restoration of normoxemia while avoiding tissue hypoxia. This review sets out to discuss the strengths and limitations of precise control of arterial oxygenation and permissive hypoxemia as candidate management strategies in hypoxemic critically ill patients. Design: we searched PubMed for references to "permissive hypoxemia/hypoxaemia" and "precise control of arterial oxygenation" as well as reference to "profound hypoxemia/hypoxaemia/hypoxia," "severe hypoxemia/hypoxaemia/hypoxia." We searched personal reference libraries in the areas of critical illness and high altitude physiology and medicine. We also identified large clinical studies in patients with critical illness characterized by hypoxemia such as acute respiratory distress syndrome. Subjects: studies were selected that explored the physiology of hypoxemia in healthy volunteers or critically ill patients. Setting: the data were subjectively assessed and combined to generate the narrative. Results: inadequate tissue oxygenation and excessive oxygen administration can be detrimental to outcome but safety thresholds lack definition in critically ill patients. Precise control of arterial oxygenation provides a rational approach to the management of arterial oxygenation that reflects recent clinical developments in other settings. Permissive hypoxemia is a concept that is untested clinically and requires robust investigation prior to consideration of implementation. Both strategies will require accurate monitoring of oxygen administration and arterial oxygenation. Effective, reliable measurement of tissue oxygenation along with the use of selected biomarkers to identify suitable candidates and monitor harm will aid the development of permissive hypoxemia as viable clinical strategy. Conclusions: implementation of precise control of arterial oxygenation may avoid the harms associated with excessive and inadequate oxygenation. However, at present there is no direct evidence to support the immediate implementation of permissive hypoxemia and a comprehensive evaluation of its value in critically ill patients should be a high research priority
Redemption in the work of Francis Stuart
No full textThe idea of redemption is central to an understanding of the work
of Francis Stuart. Through an examination of its development and
expression, it is possible to demonstrate the integrity of his work and
its distinctive qualities. Such a demonstration is necessary because
Stuart's writing has been subjected to comparatively little scholarly
inquiry, although reviews of his work, especially that produced since
1949, suggest that it is impressive and important.
First, a general background to Stuart's work, a discussion of the
special problems associated with reading it, and a summary of his corpus
is provided. This indicates that the idea of redemption is important to
his earliest writing. The state of redemption is shown to be a
necessary apotheosis for Stuart's outcast heroes; it involves spiritual
suffering through which may be found a sense of reintegration and a
higher reality. This is expressed through interrelated themes such as
those of gambler, artist and ordinary man; mystic and criminal; sacred
and profane love; and spirituality and the mundane. The nature of the
redemptive experience is further elaborated by distinctive, complex
motifs, especially the hare, the ark and the woman-Christ. Their
recurrence provides an important element in the unity of Stuart's work.
Because Stuart's idea of the outcast raises important biographical
questions, an examination of the relationship between Stuart's life and
his work is made. Finally, the way in which the idea of redemption
exists in the language structures of Stuart's novels is examined, with
especial reference to his most recent work, The High Consistory. The
thesis shows that the development of the these of redemption
demonstrates the integrity of Stuart's work
Defoe's Foes:The Author as Character
No full textThe most famous fictional Defoe features in J. M. Coetzee’s Foe (1986), in which he conjures Robinson Crusoe out of a memoir by a “true” castaway. Harrumphing across the country alongside the modern-day narrator of Stuart Campbell’s Daniel Defoe’s Railway Journey (2017), a surreal iteration quite literally leaps out of the pages of a Penguin Classics edition of his real-life counterpart’s travel writing. Setting aside a long tradition of neo-Georgian novels in which Defoe cameos as a seventeenth-century spy, a Defoe-as-character only for all intents and purposes, this chapter attends to two complex cases in the genre of author fictions: Coetzee’s Foe and Campbell’s Defoe
Ethnic identity, political identity and ethnic conflict: simulating the effect of congruence between the two identities on ethnic violence and conflict
No full textThis thesis outlines and presents an alternative hypothetical process to the emergence of ethnic conflict. Ethnic conflicts, rather than being dependent upon pre-existing 'ancient hatreds', are instead the result of a congruence between ethnic and political identity which grants individuals the ability to use ethnicity to identify and eliminate political threats. This hypothesis is formed by the examination of three case studies of ethnic conflict: Lebanon, Northern Ireland and Croatia. This hypothesis is then formalised and tested using an agent based simulation in which agent interactions are dependent upon ethnic and political identity and the congruence between the two. As predicted there was a strong positive correlation between how accurately ethnic identity reflected political identity and the level of ethnically motivated violence in the simulation, although the relationship was not linear. Furthermore the effect of a shift in congruence was found to be roughly comparable to the effect of initialising agents with a moderate level of pre-existing ethnic antagonism
Why some exotic species are deeply integrated into local cultures while others are reviled
No full textOne key challenge for invasive species management is finding support from local communities. Without local support, management plans can be severely compromised. What makes people support or reject management of invasive species can be linked to their perception of the target invasive species. In other words, it can be harder to control invasive species that are assimilated into the local community. We identify five factors associated with how quickly invasive species can become culturally assimilated. These factors are arrival time, economic impact, aesthetic value, effect on human health, and origin of nonnative species and of human immigrants. We suggest that understanding how these factors contribute to the incorporation of nonnative species into local cultures is important in determining effective control measures. In this vein, publicly accessible educational programs explaining the problems that invasive species produce will be required to implement effective invasive species management.Fil: Nuñez, Martin Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Dimarco, Romina Daniela. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Instituto de Investigaciones Forestales y Agropecuarias Bariloche. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Simberloff, Daniel. University of Tennessee; Estados Unido
sj-pdf-1-ajs-10.1177_03635465231164400 – Supplemental material for Medial Patellofemoral Ligament Reconstruction Using Allografts in Skeletally Immature Patients
No full textSupplemental material, sj-pdf-1-ajs-10.1177_03635465231164400 for Medial Patellofemoral Ligament Reconstruction Using Allografts in Skeletally Immature Patients by Martin Husen, Todd A. Milbrandt, Veeraj Shah, Aaron J. Krych, Michael J. Stuart and Daniel B.F. Saris in The American Journal of Sports Medicine</p
Effects of perioperative oxygen concentration on oxidative stress in adult surgical patients: a systematic review
No full textBackground: the fraction of inspired oxygen (FIO2) administered during general anaesthesia varies widely despite in-ternational recommendations to administer FIO20.8 to all anaesthetised patients to reduce surgical site infections (SSIs).Anaesthetists remain concerned that high FIO2administration intraoperatively may increase harm, possibly throughincreased oxidative damage. In previous systematic reviews associations between FIO2and SSIs have been inconsistent,but none have examined how FIO2affects perioperative oxidative stress. We aimed to address this uncertainty byreviewing the available literature.Methods: EMBASE, MEDLINE, and Cochrane databases were searched from inception to March 9, 2020 for RCTscomparing higher with lower perioperative FIO2and quantifying oxidative stress in adults undergoing noncardiac sur-gery. Candidate studies were independently screened by two reviewers and references hand-searched. Methodologicalquality was assessed using the Cochrane Collaboration Risk of Bias tool.Results:from 19 438 initial results, seven trials (n¼422) were included. Four studies reported markers of oxidative stressduring Caesarean section (n¼328) and three reported oxidative stress during elective colon surgery (n¼94). Risk of biaswas low (four studies) to moderate (three studies). Pooled results suggested high FIO2was associated with greatermalondialdehyde, protein-carbonyl concentrations and reduced xanthine oxidase concentrations, together with reducedantioxidant markers such as superoxide dismutase and total sulfhydryl levels although total antioxidant status wasunchanged.Conclusions: higher FIO2may be associated with elevated oxidative stress during surgery. However, limited studies havespecifically reported biomarkers of oxidation. Given the current clinical controversy concerning perioperative oxygentherapy, further research is urgently needed in this area
Oxygen targets in the intensive care unit during mechanical ventilation for acute respiratory distress syndrome: a rapid review
No full textBackground: supplemental oxygen is frequently administered to patients with acute respiratory distress syndrome (ARDS), including ARDS secondary to viral illness such as coronavirus disease 19 (COVID-19). An up-to-date understanding of how best to target this therapy (e.g. arterial partial pressure of oxygen (PaO2) or peripheral oxygen saturation (SpO2) aim) in these patients is urgently required.Objectives: to address how oxygen therapy should be targeted in adults with ARDS (particularly ARDS secondary to COVID-19 or other respiratory viruses) and requiring mechanical ventilation in an intensive care unit, and the impact oxygen therapy has on mortality, days ventilated, days of catecholamine use, requirement for renal replacement therapy, and quality of life.Search methods: we searched the Cochrane COVID-19 Study Register, CENTRAL, MEDLINE, and Embase from inception to 15 May 2020 for ongoing or completed randomized controlled trials (RCTs).Selection criteria: two review authors independently assessed all records in accordance with standard Cochrane methodology for study selection. We included RCTs comparing supplemental oxygen administration (i.e. different target PaO2 or SpO2 ranges) in adults with ARDS and receiving mechanical ventilation in an intensive care setting. We excluded studies exploring oxygen administration in patients with different underlying diagnoses or those receiving non-invasive ventilation, high-flow nasal oxygen, or oxygen via facemask.Data collection and analysis: one review author performed data extraction, which a second review author checked. We assessed risk of bias in included studies using the Cochrane 'Risk of bias' tool. We used the GRADE approach to judge the certainty of the evidence for the following outcomes; mortality at longest follow-up, days ventilated, days of catecholamine use, and requirement for renal replacement therapy.Main results: we identified one completed RCT evaluating oxygen targets in patients with ARDS receiving mechanical ventilation in an intensive care setting. The study randomized 205 mechanically ventilated patients with ARDS to either conservative (PaO2 55 to 70 mmHg, or SpO2 88% to 92%) or liberal (PaO2 90 to 105 mmHg, or SpO2 ≥ 96%) oxygen therapy for seven days. Overall risk of bias was high (due to lack of blinding, small numbers of participants, and the trial stopping prematurely), and we assessed the certainty of the evidence as very low. The available data suggested that mortality at 90 days may be higher in those participants receiving a lower oxygen target (odds ratio (OR) 1.83, 95% confidence interval (CI) 1.03 to 3.27). There was no evidence of a difference between the lower and higher target groups in mean number of days ventilated (14.0, 95% CI 10.0 to 18.0 versus 14.5, 95% CI 11.8 to 17.1); number of days of catecholamine use (8.0, 95% CI 5.5 to 10.5 versus 7.2, 95% CI 5.9 to 8.4); or participants receiving renal replacement therapy (13.7%, 95% CI 5.8% to 21.6% versus 12.0%, 95% CI 5.0% to 19.1%). Quality of life was not reported.Authors' conclusion: we are very uncertain as to whether a higher or lower oxygen target is more beneficial in patients with ARDS and receiving mechanical ventilation in an intensive care setting. We identified only one RCT with a total of 205 participants exploring this question, and rated the risk of bias as high and the certainty of the findings as very low. Further well-conducted studies are urgently needed to increase the certainty of the findings reported here. This review should be updated when more evidence is available.</p
Increased gastric-end tidal P(CO2) gap during exercise at high altitude measured by gastric tonometry
No full textUsing automated air gastric tonometry, the hypothesis that gastric perfusion is reduced while exercising at high altitude was explored. This prospective observational study of 5 well acclimatized healthy volunteers was performed during a medical research expedition to Chamlang base camp (5000 m), Hongu valley, Nepal. We used gastric tonometry at rest and during graded submaximal exercise. The end tidal partial pressure of carbon dioxide was subtracted from the gastric mucosal partial pressure of carbon dioxide to calculate the P(CO2) gradient, which is a marker of gastric mucosal perfusion. When compared with rest, there was no increase in the mean P(CO2) gradient at the lower work rate (0.22 vs. 0.18, p 0.10), but an increase was seen between rest and the higher work rate (0.22 vs. 0.77, p = 0.04). We conclude that exercising while at high altitude can lead to a raised P(CO2) gradient when gastric tonometry is performed, indicating reduced perfusion. This may represent reduced gastric mucosal perfusion under these conditions
Now for the long term: the report of the Oxford Martin Commission for Future Generations
No full textThis report is the product of a year long process of research and debate undertaken by a group of eminent leaders on the successes and failures in addressing global challenges over recent decades.
As the world slowly emerges from the devastating Financial Crisis, it is time to reflect on the lessons of this turbulent period and think afresh about how to prevent future crises.
The Oxford Martin Commission for Future Generations focuses on the increasing short-termism of modern politics and our collective inability to break the gridlock which undermines attempts to address the biggest challenges that will shape our future. In Now for the Long Term, they urge decision-makers to overcome their pressing daily preoccupations to tackle problems that will determine the lives of today’s and tomorrow’s generations. Dr James Martin, the founder of the Oxford Martin School, highlights that humanity is at a crossroads. This could be our best century ever, or our worst. The outcome will depend on our ability to understand and harness the extraordinary opportunities as well as manage the unprecedented uncertainties and risks.
The report identifies what these challenges are, explains how progress can be made, and provides practical recommendations. The Commission outlines an agenda for the long term. The case for action is built in three parts. The first, Possible Futures , identifies the key drivers of change and considers how we may address the challenges that will dominate this
century. Next, in Responsible Futures, the Commission draws inspiration from previous examples of where impediments to action have been overcome, and lessons from where progress has been stalled. We then consider the characteristics of our current national and global society that frustrate progress. The final part, Practical Futures, sets out the principles for action and offers illustrative recommendations which show how we can build a sustainable, inclusive and resilient future for all.
 
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