| 1. |
- Brauer, Kirk I, et al.
(författare)
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Hypoproteinemia does not alter plasma volume expansion in response to a 0.9% saline bolus in awake sheep
- 2010
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Ingår i: CRITICAL CARE MEDICINE. - : Williams and Wilkins. - 0090-3493 .- 1530-0293. ; 38:10, s. 2011-2015
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To test the hypothesis that hypoproteinemia reduces plasma volume expansion produced by a bolus of crystalloid solution given to awake sheep. Design: Prospective and observational. Setting: Laboratory. Subjects: Five female merino sheep (n = 5) weighing 37 +/- 3 kg were anesthetized. Interventions: Each animal was subjected to a 5-day test period: day 1: 50 mL/min 0.9% saline infusion over 20 mins. Days 2-4: daily plasmapheresis and replacement of the shed plasma with 6 L of 0.9% saline were performed in increments. Measurements and Main Results: Fractional plasma volume expansion after rapid infusion of saline on days 1 and 5 was calculated from changes in hemoglobin concentration. There was a significant reduction in total plasma protein concentration after plasmapheresis (p andlt; .05). Colloid osmotic pressures were also significantly lowered (p andlt; .05). A crystalloid infusion of 0.9% saline did not alter any of these values compared with baseline. The hemodynamic measurements did not show significant differences between the experiments. The plasma volume expansion reached approximately 20% at the end of infusion and stayed at 10-15% during the experiments. No difference was found in plasma volume expansion produced by a bolus of 50 mL/min of 0.9% in the hypoproteinemic state when compared with the euproteinemic state (p = .61). No difference in cumulative urinary output was found between the two states. Conclusions: In contrast to our hypothesis, severe acute hypoproteinemia does not reduce plasma volume expansion in response to 50 mL/min 0.9% saline infusion in nonspleenectomized sheep when compared with the resultant plasma volume expansion after a 50 mL/min of 0.9% infusion in the euproteinemic state.
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| 2. |
- Hahn, Robert G, et al.
(författare)
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Isoflurane inhibits compensatory intravascular volume expansion after hemorrhage in sheep
- 2006
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Ingår i: Anesthesia and Analgesia. - : Lippincott Williams & Wilkins. - 0003-2999 .- 1526-7598. ; 103:2, s. 350-358
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Tidskriftsartikel (refereegranskat)abstract
- After hemorrhage, blood volume is partially restored by transcapillary refill, a process of spontaneous compensatory intravascular volume expansion that we hypothesized would be inhibited by anesthesia. Six chronically instrumented sheep were subjected to four randomly ordered experiments while conscious or during anesthesia with isoflurane. After plasma volume measurement (indocyanine green), 15% or 45% of the blood volume was withdrawn. To quantify transcapillary refill, mass balance and kinetic calculations utilized repeated measurements of hemoglobin concentration, assuming that transcapillary refill would dilute hemoglobin concentration. After 15% hemorrhage, mean arterial blood pressure remained stable in both conscious and isoflurane-anesthetized sheep (normotensive hemorrhage) but decreased after 45% hemorrhage (hypotensive hemorrhage). After either normotensive or hypotensive hemorrhage, transcapillary refill occurred more rapidly during the first 40 min than during the next 140 min (P < 0.001). In conscious sheep, at 180 min, 57% and 42% of the bled volume had been restored after normotensive and hypotensive hemorrhage, respectively, in contrast to only 13% and 27% (P < 0.001) in isoflurane-anesthetized sheep. A novel kinetic model implicated hemodynamic factors in rapid, early transcapillary refill and decreased plasma oncotic pressure in subsequent slower filling. We conclude that isoflurane inhibits transcapillary refill after both normotensive and hypotensive hemorrhage in sheep.
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| 3. |
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| 4. |
- Leire, Charlotte, et al.
(författare)
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Online teaching going massive: input and outcomes
- 2016
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 123, s. 230-233
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Tidskriftsartikel (refereegranskat)abstract
- The proliferation of massive open online courses is a recent phenomenon in higher education. At the International Institute for Industrial Environmental Economics at Lund University in Sweden, emerging pedagogical approaches in e-learning have long been embraced, allowing for valuable experience with new educational technologies applied in education for sustainability. In 2014, the Institute was given a formal task to develop a massive open online course on “Greening the Economy: Lessons from Scandinavia”, thereby utilizing existing capacities and experiences while experiencing new challenges revealed by courses of larger scale. This article presents the background to the Institute's undertaking with massive open online courses and the range of expectations from the main stakeholders. The article discusses massive open online courses as a novel venue for e-learning in sustainability education as regards learning activities, design and content. It concludes that while the initial experience of such a course has been positive, in order to better cater to the learner groups, continued attention needs to be paid to course design, teacher capacity and in particular an examination of learner motivations.
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| 5. |
- Richter, Jessika Luth, et al.
(författare)
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Greening the global classroom: experiences using MOOCs to advance sustainability education
- 2015
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Ingår i: Global Cleaner Production and Sustainable Consumption Conference Proceedings.
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Konferensbidrag (refereegranskat)abstract
- The proliferation of massive open online courses (MOOCs) has been a phenomenon in higher education but only recently the subject of academic literature. MOOCs combine the traditional ideas of cohort and guided learning with open access and a truly global classroom. With over twenty thousand learners attracted to such courses, we argue that they can be a powerful tool in advancing sustainability education in terms of global reach. Like traditional education, the quality of the education delivered by MOOCs is influenced by their design and this is also integral to their success in promoting deeper learning of sustainability topics. However, designing a quality course and ensuring genuine learning experiences in this open and massive context is not without challenges. We describe our practical experience with curriculum design, production and delivery of a MOOC with a wide sustainability focus of "Greening the Economy: Lessons from Scandinavia". The background of students taking the MOOC, motivations and reasons for seeking this type of sustainability education and perceived benefits from this MOOC and other MOOCs with topics related to sustainability are discussed. Combining pedagogical approaches in the form of teacher-led lectures and quizzes for basic understanding with more constructivist forum discussions and peer assessment created the opportunity for the MOOC to not only disseminate knowledge about sustainability issues, but also encourage discussion, peer interaction, and deeper engagement with these issues. An interesting aspect of this reciprocal learning was the collected insights from learners in the form of case studies and survey responses. The promise, as well as potential issues, of MOOCs in contributing to the goals of sustainability education and lifelong learning are discussed and reflected upon.
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| 6. |
- Rockström, Johan, et al.
(författare)
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A safe operating space for humanity
- 2009
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 461:7263, s. 472-475
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Rockström, Johan, et al.
(författare)
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Planetary Boundaries : Exploring the Safe Operating Space for Humanity
- 2009
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Ingår i: Ecology & Society. - 1708-3087. ; 14:2, s. 32-
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems. We have identified nine planetary boundaries and, drawing upon current scientific understanding, we propose quantifications for seven of them. These seven are climate change (CO2 concentration in the atmosphere <350 ppm and/or a maximum change of +1 W m(-2) in radiative forcing); ocean acidification (mean surface seawater saturation state with respect to aragonite >= 80% of pre-industrial levels); stratospheric ozone (<5% reduction in O-3 concentration from pre-industrial level of 290 Dobson Units); biogeochemical nitrogen (N) cycle (limit industrial and agricultural fixation of N-2 to 35 Tg N yr(-1)) and phosphorus (P) cycle (annual P inflow to oceans not to exceed 10 times the natural background weathering of P); global freshwater use (<4000 km(3) yr(-1) of consumptive use of runoff resources); land system change (<15% of the ice-free land surface under cropland); and the rate at which biological diversity is lost (annual rate of <10 extinctions per million species). The two additional planetary boundaries for which we have not yet been able to determine a boundary level are chemical pollution and atmospheric aerosol loading. We estimate that humanity has already transgressed three planetary boundaries: for climate change, rate of biodiversity loss, and changes to the global nitrogen cycle. Planetary boundaries are interdependent, because transgressing one may both shift the position of other boundaries or cause them to be transgressed. The social impacts of transgressing boundaries will be a function of the social-ecological resilience of the affected societies. Our proposed boundaries are rough, first estimates only, surrounded by large uncertainties and knowledge gaps. Filling these gaps will require major advancements in Earth System and resilience science. The proposed concept of "planetary boundaries" lays the groundwork for shifting our approach to governance and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative externalities, toward the estimation of the safe space for human development. Planetary boundaries define, as it were, the boundaries of the "planetary playing field" for humanity if we want to be sure of avoiding major human-induced environmental change on a global scale.
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| 8. |
- Rodhe, Peter M
(författare)
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Mathematical modelling of clinical applications in fluid therapy
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: This thesis presents a new application of fluid kinetic analysis using mathematical tools to evaluate fluid therapy problems. Several models were developed to mathematically handle fluid distribution concerning bleeding and anaesthesia, arterio-venous differences in plasma dilution, peripheral fluid accumulation and differences in fluid distribution among young and elderly patients. Non-linear regression models were used to fit equations to sampled haemoglobin data. Methods: I: Six chronically instrumented sheep were subjected to four randomly ordered experiments while conscious or during anesthesia with isoflurane. After plasma volume measurement 15% or 45% of the blood volume was withdrawn. To quantify transcapillary refill, mass balance and kinetic calculations utilized repeated measurements of haemoglobin concentration. II: Fifteen volunteers received an intravenous (iv) infusion of 15 mL/kg of lactated Ringer s solution during 10 min. Simultaneous arterial and venous blood haemoglobin (Hb) samples were obtained and Hb concentrations measured. III: Ten healthy female non-pregnant volunteers participated. The protocol included an infusion of acetated Ringer s solution, 25 ml/kg over 30 minutes. Blood samples were repeatedly. A standard bladder catheter was continuously monitoring urine excretion. Plasma dilution, peripheral accumulation and urine output were modelled simultaneously. IV: Twenty four volunteers participated. Two age groups, a young group (age 18-25) and an elderly group (age 70-90) were formed. On separate occasions, the subjects in both groups were given a crystalloid 25 mg/ml glucose solution, either orally (ORAL) or intravenously (IV) in a crossover design with at least two weeks in between. On each occasion, the subjects got 7 ml/kg of the crystalloid solution during 15 minutes. Results: I: After either normotensive or hypotensive hemorrhage, transcapillary refill occurred more rapidly during the first 40 min than during the next 140 min (p < 0.001). In conscious sheep, at 180 min, 57% and 42% of the bled volume had been restored after normotensive and hypotensive hemorrhage, respectively, in contrast to only 13% and 27% (p < 0.001) in isoflurane-anesthetized sheep. Using parameters derived from kinetic analysis, simulations illustrate that both the hydrostatic and colloid osmotic forces are weaker in the presence of isoflurane than in the awake state. II: The AV difference in plasma dilution was only positive during the infusion and for 2.5 min thereafter, which represents the period of net flow of fluid from plasma to tissue. Kinetic analysis showed that volume expansion of the peripheral fluid space began to decrease 14 min (arterial blood) and 20 min (venous blood) after the infusion ended. III: Maximum urinary output rate was found to be 19 (13 31) ml/min. The subjects were likely to accumulate three times as much of the infused fluid peripherally as centrally; Elimination efficacy, Eeff, was 24 (5 35) and the basal elimination kb was 1.11 (0.28 2.90). The total time delay Ttot of urinary output was estimated to 17 (11 - 31) min. IV: The lag-time of glucose given orally was estimated to be 17 (8 25) min for the younger group and 18 (13 22) min for the elderly. For fluid, the lag-time was estimated to 29 (21 - 34) min for the younger and 25 (16 39) min for the elderly. Conclusions: Final conclusion is that mathematical modelling of clinical applications can be done in several different clinical settings and will improve the understanding of fluid distribution. It is possible to continuously model fluid behaviour in the body as seen in Papers II-III. This should enhance the understanding of accumulating oedema in the body which is an apparent problem for all clinicians.
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| 9. |
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| 10. |
- Sicardi Salomón, Z., et al.
(författare)
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Progressive decrease in glucose clearance during surgery
- 2006
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley-Blackwell. - 0001-5172 .- 1399-6576. ; 50:7, s. 848-854
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Anaesthesia and surgery reduce the clearance of glucose. We studied how surgical procedures of different magnitude affect the clearance of a glucose load.METHODS: An intravenous infusion of 10 ml/kg/h of 2.5% buffered glucose was given over 80 min to 26 patients with a mean age of 50 years. The infusion started with the skin incision during minor surgery (inguinal hernia repair), medium-range surgery (laparoscopic cholecystectomy) and major surgery (aortic surgery, gastrectomy or colorectal surgery). General anaesthesia was induced in all patients and was supplemented by thoracic epidural analgesia for those undergoing major surgery. Plasma glucose was measured repeatedly for comparison of the clearance and endogenous glucose production during and after the infusion.RESULTS: Metabolic changes affected the shape of the plasma glucose curves more than the peak values. In those undergoing minor surgery, the clearance after the infusion was 65% of that recorded during the actual administration of glucose. The corresponding values for medium-range and major surgery were 37% and 60%, respectively (P < 0.001). The limited decrease in clearance in major surgery can probably be attributed to the epidural analgesia. In all three groups, the estimated endogenous glucose production decreased by the same magnitude as the clearance. The volume of distribution for glucose averaged 10.3 l.CONCLUSION: The hyperglycaemic effect of anaesthesia and surgery was not fully expressed within 80 min, regardless of the extent of surgery, and therefore appears to develop slowly. Even minor surgical trauma affected the metabolism of glucose.
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