Mg, Ca and Sr isotope dynamics in a small forested catchment underlain by paragneiss: The role of geogenic, atmospheric, and biogenic sources of base cations

Knowledge of the origin of magnesium (Mg) and calcium (Ca) in soil solutions and catchment runoff helps to predict forest ecosystems’ vulnerability to deficiencies in essential nutrients in an era of climate change, environmental pollution and bark-beetle calamities. Here we discuss isotope aspects of Mg, Ca and strontium (Sr) cycling in a spruce-forested headwater catchment in a relatively unpolluted part of Central Europe. We investigated to what extent Mg and Ca isotope signatures of runoff reflect the isotope compositions of specific Mg- and Ca-rich minerals that easily dissolve during the weathering of paragneiss, and compared the isotope variability of Mg and Ca in fresh bedrock minerals, soils and other ecosystem reservoirs. We also compared conclusions from Mg and Ca isotope systematics with inferences from catchment input–output mass budgets. Long-term input–output monitoring in the studied catchment situated near the Czech–German border (Central Europe) revealed 3.5–7 times higher outputs of Mg, Ca, and Sr via surface runoff relative to their present-day atmospheric inputs. It follows that hydrological exports of recent atmospheric Mg, Ca and Sr are minor. Release of geogenic base cations into the runoff results from the interplay between mineral abundances, concentrations of the studied elements in the minerals, and their dissolution rates. Chemical depletion fractions for the studied elements from bedrock to the soil were 50–70 %, and the losses of dominant soluble minerals in the soil were 30–80 %. Exports of residual Mg, Ca and Sr following partial incorporation of these elements into secondary phyllosilicates are probably low because newly-formed clay minerals are not abundant in the soil. Residual Ca following preferential incorporation of isotopically light Ca into growing tree biomass may contribute to the isotopically heavy runoff Ca. Isotope ratios of base cations were obtained for six minerals (plagioclase, orthoclase, biotite, muscovite, apatite, and ilmenite). Mineral fractions differ greatly in δ²⁶Mg and δ⁴⁴Ca values and ⁸⁷Sr/⁸⁶Sr ratios. 80–97 % of each of the three studied base cations are present in the bedrock in a single relatively easily dissolvable mineral: Mg in biotite, and Ca and Sr in plagioclase. The isotope composition of Mg in biotite was similar to the isotope composition of Mg in runoff. The isotope compositions of Ca and Sr in plagioclase were also similar to Ca and Sr isotope compositions in runoff. Thus, the dominant geogenic source of each of the studied elements (Mg, Ca and Sr) in the investigated paragneiss catchment can be represented by one relatively soluble mineral.ISSN:0016-7061ISSN:1872-625

Intraoperative transfusion practices in Europe

Transfusion of allogeneic blood influences outcome after surgery. Despite widespread availability of transfusion guidelines, transfusion practices might vary among physicians, departments, hospitals and countries. Our aim was to determine the amount of packed red blood cells (pRBC) and blood products transfused intraoperatively, and to describe factors determining transfusion throughout Europe. We did a prospective observational cohort study enrolling 5803 patients in 126 European centres that received at least one pRBC unit intraoperatively, during a continuous three month period in 2013. The overall intraoperative transfusion rate was 1.8%; 59% of transfusions were at least partially initiated as a result of a physiological transfusion trigger- mostly because of hypotension (55.4%) and/or tachycardia (30.7%). Haemoglobin (Hb)- based transfusion trigger alone initiated only 8.5% of transfusions. The Hb concentration [mean (sd)] just before transfusion was 8.1 (1.7) g dl and increased to 9.8 (1.8) g dl after transfusion. The mean number of intraoperatively transfused pRBC units was 2.5 (2.7) units (median 2). Although European Society of Anaesthesiology transfusion guidelines are moderately implemented in Europe with respect to Hb threshold for transfusion (7-9 g dl), there is still an urgent need for further educational efforts that focus on the number of pRBC units to be transfused at this threshold

Intraoperative transfusion practices in Europe

© 2016 The Author. Published by Oxford University Press on behalf of the British Journal of Anaesthesia.Background: Transfusion of allogeneic blood influences outcome after surgery. Despite widespread availability of transfusion guidelines, transfusion practices might vary among physicians, departments, hospitals and countries. Our aim was to determine the amount of packed red blood cells (pRBC) and blood products transfused intraoperatively, and to describe factors determining transfusion throughout Europe. Methods: We did a prospective observational cohort study enrolling 5803 patients in 126 European centres that received at least one pRBC unit intraoperatively, during a continuous three month period in 2013. Results: The overall intraoperative transfusion rate was 1.8%; 59% of transfusions were at least partially initiated as a result of a physiological transfusion trigger- mostly because of hypotension (55.4%) and/or tachycardia (30.7%). Haemoglobin (Hb)- based transfusion trigger alone initiated only 8.5% of transfusions. The Hb concentration [mean (sd)] just before transfusion was 8.1 (1.7) g dl-1 and increased to 9.8 (1.8) g dl-1 after transfusion. The mean number of intraoperatively transfused pRBC units was 2.5 (2.7) units (median 2). Conclusions: Although European Society of Anaesthesiology transfusion guidelines are moderately implemented in Europe with respect to Hb threshold for transfusion (7-9 g dl-1), there is still an urgent need for further educational efforts that focus on the number of pRBC units to be transfused at this threshold

Intraoperative transfusion practices and perioperative outcome in the European elderly: A secondary analysis of the observational ETPOS study

The demographic development suggests a dramatic growth in the number of elderly patients undergoing surgery in Europe. Most red blood cell transfusions (RBCT) are administered to older people, but little is known about perioperative transfusion practices in this population. In this secondary analysis of the prospective observational multicentre European Transfusion Practice and Outcome Study (ETPOS), we specifically evaluated intraoperative transfusion practices and the related outcomes of 3149 patients aged 65 years and older. Enrolled patients underwent elective surgery in 123 European hospitals, received at least one RBCT intraoperatively and were followed up for 30 days maximum. The mean haemoglobin value at the beginning of surgery was 108 (21) g/l, 84 (15) g/l before transfusion and 101 (16) g/l at the end of surgery. A median of 2 [1–2] units of RBCT were administered. Mostly, more than one transfusion trigger was present, with physiological triggers being preeminent. We revealed a descriptive association between each intraoperatively administered RBCT and mortality and discharge respectively, within the first 10 postoperative days but not thereafter. In our unadjusted model the hazard ratio (HR) for mortality was 1.11 (95% CI: 1.08–1.15) and the HR for discharge was 0.78 (95% CI: 0.74–0.83). After adjustment for several variables, such as age, preoperative haemoglobin and blood loss, the HR for mortality was 1.10 (95% CI: 1.05–1.15) and HR for discharge was 0.82 (95% CI: 0.78–0.87). Preoperative anaemia in European elderly surgical patients is undertreated. Various triggers seem to support the decision for RBCT. A closer monitoring of elderly patients receiving intraoperative RBCT for the first 10 postoperative days might be justifiable. Further research on the causal relationship between RBCT and outcomes and on optimal transfusion strategies in the elderly population is warranted. A thorough analysis of different time periods within the first 30 postoperative days is recommended