Preferences for the measurement and supplementation of magnesium, phosphate and zinc in ICUs: The international WhyTrace survey.

BACKGROUND: Patients admitted to the Intensive Care Unit (ICU) often have low magnesium, phosphate and zinc levels. Monitoring of serum concentrations and supplementation may be important, but there is no consensus on optimal practice. The objective of the WhyTrace survey was to describe current practice regarding the measurement and supplementation of magnesium, phosphate and zinc in ICUs. METHODS: A 54-item electronic questionnaire was developed in accordance with SURGE, SUrvey Reporting GuidelinE, to address international clinical practice in the ICU. National investigators recruited ICUs in ten countries with one physician responding per ICU using a unique e-mail distributed survey-link. RESULTS: The questionnaire was sent to clinicians in 336 ICUs of whom 283 (84%) responded. In 62% of the ICUs, a standard procedure was in place regarding the measurement of serum magnesium levels, in 58% for phosphate and in 9% for zinc. Zinc was never or rarely measured in 64% of ICUs. The frequency of requesting serum levels varied from twice daily to once weekly. Regarding supplementation, 66% of ICUs had a standard procedure for magnesium, 63% for phosphate and 15% for zinc. Most procedures recommended supplementation when serum levels were below the lower reference level, but some used the upper reference levels as the threshold for supplementation and others decided on a case-by-case basis. CONCLUSION: The practice of measuring and supplementing magnesium, phosphate and zinc differed substantially between ICUs. Our findings indicate that there is a need for high-quality prospective data on frequencies of measurements, treatment goals and effects of supplementation on patient-important outcomes.

Long-range symmetry breaking in embedded ferroelectrics.

The characteristic functionality of ferroelectric materials is due to the symmetry of their crystalline structure. As such, ferroelectrics lend themselves to design approaches that manipulate this structural symmetry by introducing extrinsic strain. Using in situ dark-field X-ray microscopy to map lattice distortions around deeply embedded domain walls and grain boundaries in BaTiO3, we reveal that symmetry-breaking strain fields extend up to several micrometres from domain walls. As this exceeds the average domain width, no part of the material is elastically relaxed, and symmetry is universally broken. Such extrinsic strains are pivotal in defining the local properties and self-organization of embedded domain walls, and must be accounted for by emerging computational approaches to material design.

Single-photon ionization of organic molecules beyond 10 kDa.

The volatilization and soft ionization of complex neutral macromolecules at low energies has remained an outstanding challenge for several decades. Most volatilization techniques in mass spectrometry produce ions already in the source and most of them lead to particle velocities in excess of several hundred meters per second. For many macromolecules, post-ionization is inefficient since electronic or optical excitations can be followed by competing non-ionizing internal conversion, electron recapture, or fragmentation processes. Here, we explore the laser-assisted volatilization of neutral perfluoroalkyl-functionalized tetraphenylporphyrins as well as their single-photon ionization using vacuum ultraviolet (VUV) light at 157 nm. A systematic investigation of the ionization curves allows us to determine the molecular velocity distribution and ionization cross sections. We demonstrate the detection of single photon ionized intact organic molecules in excess of 10 kDa from a slow molecular beam.

Extracorporeal membrane oxygenation for acute respiratory distress syndrome: is the configuration mode an important predictor for the outcome?

Extracorporeal membrane oxygenation (ECMO) is increasingly applied as rescue-therapy for patients with severe acute respiratory distress syndrome (ARDS). Here, we evaluate the effect of different configuration strategies (venovenous vs. venoarterial vs. veno-venoarterial) on the outcome. From 2006 to 2008, 30 patients received ECMO for severe ARDS. Patients were divided into three groups according to the configuration: veno-venous (vv; n = 11), venoarterial (va; n=8) or veno-venoarterial (vva; n = 11). Data were prospectively collected and endpoint was 30-day mortality. To identify independent risk factors, univariate analysis was performed for clinical parameters, such as age, body mass index, gender, configuration, low-pH, oxygenation index (pO(2)/FiO(2)) and underlying disease. Thirty-day mortality was 53% (n = 16) for all comers: 63% (n = 7) died in the vv-group, 75% (n = 6) in the va-group and 27% (n = 3) in the vva-group. Although univariate analysis could not rule out a significant predictor for the outcome, there was a trend visible to decreased mortality in the vva-group when compared to vv- and va-groups (27% vs. 63% vs. 75%; P = 0.057). ECMO provides a survival benefit in patients when considering a predicted mortality rate of 80% in ARDS. The configuration mode appears to impact the outcome as the veno-venoarterial appears to further improve the survival in this subset of patients.