The use of the laryngeal tube disposable by paramedics during out-of-hospital cardiac arrest: a prospectively observational study (2008–2012

Summary: In the previous and the current guidelines of the European Resuscitation Council (ERC), endotracheal intubation (ETI), as an instrument for ventilation during resuscitation, was confirmed as less important for paramedics not trained in this method. For those, during resuscitation, the laryngeal tube is recommended by the ERC as a supraglottic airway device. The present study investigated prospectively the use of the laryngeal tube disposable (LT-D) by paramedics in prehospital emergency cases. Methods: During a 42-month period (Sept 2008–Feb 2012), we prospectively registered all prehospital cardiac arrest situations in which the LT-D had been applied by paramedics (from one emergency medical service in Germany). Results: During the defined period, 133 attempts, recorded on standardised data sheets, were enrolled into the investigation. Three were excluded from the study because of use during a trauma situation. Therefore, 130 patients were evaluated in this study. For this, the LT-D was used in 98% of all cases during resuscitation, and in about 2% of other emergencies (eg, trauma). With regard to resuscitation, adequate ventilation/oxygenation was described as possible in 83% of all included cases. In 66% of all cases, no problems concerning the insertion of the LT-D were described by the paramedics. No significant problems were reported in 93%. In 7% (n=9 cases), no insertion of the LT-D was possible. Instead of bag-mask-valve ventilation, the LT-D was used as a first-line airway device in about 66%. Between the two defined groups, no statistically significant differences were found (p>0.05). Conclusions: As an alternative airway device during resuscitation, recommended by the ERC in 2005 and 2010, the LT-D may enable ventilation rapidly and, as in most of our described cases, effectively. Additionally, by using the LT-D in a case of cardiac arrest, a reduced ‘hands-off time’ and, therefore, a high chest compression rate may be possible. Our investigation showed that the LT-D was often used as an alternative to bag-mask-ventilation and to ETI as well. However, we were able to describe more problems in the use of the LT-D than earlier investigations. Therefore, in future, more studies concerning the use of alternative airway devices in comparison with ETI and/or video-laryngoscopy seem to be necessary

Mineralogical and geochemical analysis of Fe-phases in drill-cores from the Triassic Stuttgart Formation at Ketzin CO₂ storage site before CO₂ arrival

Reactive iron (Fe) oxides and sheet silicate-bound Fe in reservoir rocks may affect the subsurface storage of CO2 through several processes by changing the capacity to buffer the acidification by CO2 and the permeability of the reservoir rock: (1) the reduction of three-valent Fe in anoxic environments can lead to an increase in pH, (2) under sulphidic conditions, Fe may drive sulphur cycling and lead to the formation of pyrite, and (3) the leaching of Fe from sheet silicates may affect silicate diagenesis. In order to evaluate the importance of Fe-reduction on the CO2 reservoir, we analysed the Fe geochemistry in drill-cores from the Triassic Stuttgart Formation (Schilfsandstein) recovered from the monitoring well at the CO2 test injection site near Ketzin, Germany. The reservoir rock is a porous, poorly to moderately cohesive fluvial sandstone containing up to 2–4 wt% reactive Fe. Based on a sequential extraction, most Fe falls into the dithionite-extractable Fe-fraction and Fe bound to sheet silicates, whereby some Fe in the dithionite-extractable Fe-fraction may have been leached from illite and smectite. Illite and smectite were detected in core samples by X-ray diffraction and confirmed as the main Fe-containing mineral phases by X-ray absorption spectroscopy. Chlorite is also present, but likely does not contribute much to the high amount of Fe in the silicate-bound fraction. The organic carbon content of the reservoir rock is extremely low (<0.3 wt%), thus likely limiting microbial Fe-reduction or sulphate reduction despite relatively high concentrations of reactive Fe-mineral phases in the reservoir rock and sulphate in the reservoir fluid. Both processes could, however, be fuelled by organic matter that is mobilized by the flow of supercritical CO2 or introduced with the drilling fluid. Over long time periods, a potential way of liberating additional reactive Fe could occur through weathering of silicates due to acidification by CO2

Mass balance of the Greenland and Antarctic ice sheets from 1992 to 2020

Ice losses from the Greenland and Antarctic ice sheets have accelerated since the 1990s, accounting for a significant increase in the global mean sea level. Here, we present a new 29-year record of ice sheet mass balance from 1992 to 2020 from the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE). We compare and combine 50 independent estimates of ice sheet mass balance derived from satellite observations of temporal changes in ice sheet flow, in ice sheet volume, and in Earth's gravity field. Between 1992 and 2020, the ice sheets contributed 21.0±1.9g€¯mm to global mean sea level, with the rate of mass loss rising from 105g€¯Gtg€¯yr-1 between 1992 and 1996 to 372g€¯Gtg€¯yr-1 between 2016 and 2020. In Greenland, the rate of mass loss is 169±9g€¯Gtg€¯yr-1 between 1992 and 2020, but there are large inter-annual variations in mass balance, with mass loss ranging from 86g€¯Gtg€¯yr-1 in 2017 to 444g€¯Gtg€¯yr-1 in 2019 due to large variability in surface mass balance. In Antarctica, ice losses continue to be dominated by mass loss from West Antarctica (82±9g€¯Gtg€¯yr-1) and, to a lesser extent, from the Antarctic Peninsula (13±5g€¯Gtg€¯yr-1). East Antarctica remains close to a state of balance, with a small gain of 3±15g€¯Gtg€¯yr-1, but is the most uncertain component of Antarctica's mass balance. The dataset is publicly available at 10.5285/77B64C55-7166-4A06-9DEF-2E400398E452 (IMBIE Team, 2021)