Ion‐microprobe 206Pb/238U geochronology and trace element geochemistry of the unpolished rims and sectioned interiors of zircons from Yellowstone caldera's oldest post‐caldera lavas provide insight into the magmatic system during the prelude and aftermath of the caldera‐forming Lava Creek supereruption. The post‐caldera lavas compose the Upper Basin Member of the Plateau Rhyolite and fall into two groups based on zircon crystallization age: early lavas with zircon ages between ~750 and 550 ka and late lavas with zircon ages between ~350 and 250 ka. Zircons from the early‐erupted East Biscuit Basin flow yield U‐Pb dates and trace element compositions, which when considered with the Pb isotopic compositions of their coexisting feldspars and pyroxenes, point to an isotopically distinct parental melt present during crystallization of the Lava Creek magma but untapped by the supereruption. Distinct zircon crystallization ages and Pb‐isotope compositions of major minerals between the early and late Upper Basin Member groups suggest contrasting sources in the magma reservoir. As proxies for melt evolution, the zircons indicate that Yellowstone's post‐caldera rhyolites became more evolved between mid‐ to late‐Pleistocene time, during the same interval that melting of hydrothermally altered wall rock and recharge by new silicic magmas changed in their relative roles. The results from this study indicate that discrete and ephemeral bodies of silicic magma, at times within a mush dominated reservoir and including during the prelude to the Lava Creek eruption, have characterized Yellowstone's subvolcanic reservoir.
Membrane pressure monitoring during extracorporeal membrane oxygenation (ECMO) is integral to monitoring circuit health. We compared a disposable vascular pressure device (DVPD) to the transducer pressure bag arterial line (TPBAL) monitoring system to determine whether the DVPD can reliably and accurately monitor membrane pressures during venovenous extracorporeal membrane oxygenation (VV ECMO). We analyzed existing quality assurance data collected at a single center as part of routine circuit performance monitoring and process improvement on a convenience sample of four VV ECMO circuits. We placed and zeroed a DVPD in line with the pre- and postmembrane TPBAL setups in coordination with a standard transducer setup. We recorded DVPD and TPBAL pressure measurements every 4 hours for 2.5 days on the four separate VV ECMO circuits. We compared the standard and DVPD pressures using Bland–Altman plots and methods that accounted for repeated measures in the same subject. We recorded 58 pre/postmembrane pressures. Mean membrane pressure values were similar in the DVPD (pre: 208 mmHg [SD, 50.8]; post: 175 mmHg [46.3]) compared to the standard TPBAL setup (pre: 205 mmHg [52.0]; post: 177 mmHg [46.3]). Using Bland–Altman methods, premembrane pressures were found to be 2.2 mmHg higher (95% confidence interval [CI]: −5.3 to 9.7) in the standard TPBAL setup compared to DVPD and 1.8 mmHg higher (95% CI: −5.3 to 8.9) than the postmembrane pressures. The DVPD provided an accurate measurement of circuit pressure as compared to the TPBAL setup. Across the range of pre- and postmembrane pressures, both methods reliably agreed. Future trials should investigate DVPD accuracy in different environments such as prehospital field cannulation or critical care transport of ECMO patients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.