Association between trends in clinical variables and outcome in intensive care patients with faecal peritonitis: analysis of the GenOSept cohort.

INTRODUCTION Patients admitted to intensive care following surgery for faecal peritonitis present particular challenges in terms of clinical management and risk assessment. Collaborating surgical and intensive care teams need shared perspectives on prognosis. We aimed to determine the relationship between dynamic assessment of trends in selected variables and outcomes. METHODS We analysed trends in physiological and laboratory variables during the first week of intensive care unit (ICU) stay in 977 patients at 102 centres across 16 European countries. The primary outcome was 6-month mortality. Secondary endpoints were ICU, hospital and 28-day mortality. For each trend, Cox proportional hazards (PH) regression analyses, adjusted for age and sex, were performed for each endpoint. RESULTS Trends over the first 7 days of the ICU stay independently associated with 6-month mortality were worsening thrombocytopaenia (mortality: hazard ratio (HR) = 1.02; 95% confidence interval (CI), 1.01 to 1.03; P <0.001) and renal function (total daily urine output: HR =1.02; 95% CI, 1.01 to 1.03; P <0.001; Sequential Organ Failure Assessment (SOFA) renal subscore: HR = 0.87; 95% CI, 0.75 to 0.99; P = 0.047), maximum bilirubin level (HR = 0.99; 95% CI, 0.99 to 0.99; P = 0.02) and Glasgow Coma Scale (GCS) SOFA subscore (HR = 0.81; 95% CI, 0.68 to 0.98; P = 0.028). Changes in renal function (total daily urine output and renal component of the SOFA score), GCS component of the SOFA score, total SOFA score and worsening thrombocytopaenia were also independently associated with secondary outcomes (ICU, hospital and 28-day mortality). We detected the same pattern when we analysed trends on days 2, 3 and 5. Dynamic trends in all other measured laboratory and physiological variables, and in radiological findings, changes inrespiratory support, renal replacement therapy and inotrope and/or vasopressor requirements failed to be retained as independently associated with outcome in multivariate analysis. CONCLUSIONS Only deterioration in renal function, thrombocytopaenia and SOFA score over the first 2, 3, 5 and 7 days of the ICU stay were consistently associated with mortality at all endpoints. These findings may help to inform clinical decision making in patients with this common cause of critical illness.

Reconsidering the logic of World Federation of Neurosurgical Societies grading in patients with severe subarachnoid hemorrhage.

OBJECT Current data show a favorable outcome in up to 50% of patients with World Federation of Neurosurgical Societies (WFNS) Grade V subarachnoid hemorrhage (SAH) and a rather poor prediction of worst cases. Thus, the usefulness of the current WFNS grading system for identifying the worst scenarios for clinical studies and for making treatment decisions is limited. One reason for this lack of differentiation is the use of "negative" or "silent" diagnostic signs as part of the WFNS Grade V definition. The authors therefore reevaluated the WFNS scale by using "positive" clinical signs and the logic of the Glasgow Coma Scale as a progressive herniation score. METHODS The authors performed a retrospective analysis of 182 patients with SAH who had poor grades on the WFNS scale. Patients were graded according to the original WFNS scale and additionally according to a modified classification, the WFNS herniation (hWFNS) scale (Grade IV, no clinical signs of herniation; Grade V, clinical signs of herniation). The prediction of poor outcome was compared between these two grading systems. RESULTS The positive predictive values of Grade V for poor outcome were 74.3% (OR 3.79, 95% CI 1.94-7.54) for WFNS Grade V and 85.7% (OR 8.27, 95% CI 3.78-19.47) for hWFNS Grade V. With respect to mortality, the positive predictive values were 68.3% (OR 3.9, 95% CI 2.01-7.69) for WFNS Grade V and 77.9% (OR 6.22, 95% CI 3.07-13.14) for hWFNS Grade V. CONCLUSIONS Limiting WFNS Grade V to the positive clinical signs of the Glasgow Coma Scale such as flexion, extension, and pupillary abnormalities instead of including "no motor response" increases the prediction of mortality and poor outcome in patients with severe SAH.

Lateral impact in closed head injury: A substantially increased risk for diffuse axonal injury—A preliminary study

OBJECTIVE: Assessment, whether location of impact causing different facial fracture patterns was associated with diffuse axonal injury in patients with severe closed head injury. METHODS: Retrospectively all patients referred to the Trauma Unit of the University Hospital of Zurich, Switzerland between 1996 and 2002 presenting with severe closed head injuries (Abbreviated Injury Scale (AIS) (face) of 2-4 and an AIS (head and neck) of 3-5) were assessed according to the Glasgow Coma Scale (GCS) and the Injury Severity Score (ISS). Facial fracture patterns were classified as resulting from frontal, oblique or lateral impact. All patients had undergone computed tomography. The association between impact location and diffuse axonal injury when correcting for the level of consciousness (using the Glasgow scale) and severity of injury (using the ISS) was calculated with a multivariate regression analysis. RESULTS: Of 200 screened patients, 61 fulfilled the inclusion criteria for severe closed head injury. The medians (interquartile ranges 25;75) for GCS, AIS(face) AIS(head and neck) and ISS were 3 (3;13), 2 (2;4), 4 (4;5) and 30 (24;41), respectively. A total of 51% patients had frontal, 26% had an oblique and 23% had lateral trauma. A total of 21% patients developed diffuse axonal injury (DAI) when compared with frontal impact, the likelihood of diffuse axonal injury increased 11.0 fold (1.7-73.0) in patients with a lateral impact. CONCLUSIONS: Clinicians should be aware of the substantial increase of diffuse axonal injury related to lateral impact in patients with severe closed head injuries.

Development of a low energy ion source for ROSINA ion mode calibration

The European Rosetta mission on its way to comet 67P/Churyumov-Gerasimenko will remain for more than a year in the close vicinity (1 km) of the comet. The two ROSINA mass spectrometers on board Rosetta are designed to analyze the neutral and ionized volatile components of the cometary coma. However, the relative velocity between the comet and the spacecraft will be minimal and also the velocity of the outgassing particles is below 1km∕s. This combination leads to very low ion energies in the surrounding plasma of the comet, typically below 20eV. Additionally, the spacecraft may charge up to a few volts in this environment. In order to simulate such plasma and to calibrate the mass spectrometers, a source for ions with very low energies had to be developed for the use in the laboratory together with the different gases expected at the comet. In this paper we present the design of this ion source and we discuss the physical parameters of the ion beam like sensitivity, energy distribution, and beam shape. Finally, we show the first ion measurements that have been performed together with one of the two mass spectrometers.

Kelvin-Helmholtz instabilities at the magnetic cavity boundary of comet 67P/Churyumov-Gerasimenko

We investigate the plasma environment of comet 67P/Churyumov-Gerasimenko, the target of the European Space Agency's Rosetta mission. Rosetta will rendezvous with the comet in 2014 at almost 3.5 AU and follow it all the way to and past perihelion at 1.3 AU. During its journey towards the inner solar system the comet's environment will significantly change. The interaction of the solar wind with a well developed neutral coma leads to the formation of an upstream bow shock and, closer to the comet, the inner shock separating the solar wind, with cometary pick-up ions mass-loaded, from the inner cometary ions which are dragged outward through abundant collisions and charge exchange with the expanding neutral gas. As a consequence the interplanetary magnetic field is prevented from penetrating the innermost region of the comet, the so-called magnetic cavity. We use our magnetohydrodynamics model BATSRUS (Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme) to simulate the solar wind - comet interaction. The model includes photoionization, ion-electron recombination, and charge exchange. Under certain conditions our model predicts an unstable plasma flow at the inner shock. We show that the plasma shear flow around the magnetic cavity can lead to Kelvin-Helmholtz instabilities. We investigate the onset of this phenomenon with change of heliocentric distance and furthermore show that a previously stable magnetic cavity boundary can become unstable when the neutral gas is predominately released from the dayside of the comet.

Plasma environment of a weak comet – Predictions for Comet 67P/Churyumov–Gerasimenko from multifluid-MHD and Hybrid models

The interaction of a comet with the solar wind undergoes various stages as the comet’s activity varies along its orbit. For a comet like 67P/Churyumov–Gerasimenko, the target comet of ESA’s Rosetta mission, the various features include the formation of a Mach cone, the bow shock, and close to perihelion even a diamagnetic cavity. There are different approaches to simulate this complex interplay between the solar wind and the comet’s extended neutral gas coma which include magnetohydrodynamics (MHD) and hybrid-type models. The first treats the plasma as fluids (one fluid in basic single fluid MHD) and the latter treats the ions as individual particles under the influence of the local electric and magnetic fields. The electrons are treated as a charge-neutralizing fluid in both cases. Given the different approaches both models yield different results, in particular for a low production rate comet. In this paper we will show that these differences can be reduced when using a multifluid instead of a single-fluid MHD model and increase the resolution of the Hybrid model. We will show that some major features obtained with a hybrid type approach like the gyration of the cometary heavy ions and the formation of the Mach cone can be partially reproduced with the multifluid-type model.

The calculation of Afρ and mass loss rate for comets

Ab initio calculations of Afρ are presented using Mie scattering theory and a Direct Simulation Monte Carlo (DSMC) dust outflow model in support of the Rosetta mission and its target 67P/Churyumov-Gerasimenko (CG). These calculations are performed for particle sizes ranging from 0.010 μm to 1.0 cm. The present status of our knowledge of various differential particle size distributions is reviewed and a variety of particle size distributions is used to explore their effect on Afρ , and the dust mass production View the MathML sourcem˙. A new simple two parameter particle size distribution that curtails the effect of particles below 1 μm is developed. The contributions of all particle sizes are summed to get a resulting overall Afρ. The resultant Afρ could not easily be predicted a priori and turned out to be considerably more constraining regarding the mass loss rate than expected. It is found that a proper calculation of Afρ combined with a good Afρ measurement can constrain the dust/gas ratio in the coma of comets as well as other methods presently available. Phase curves of Afρ versus scattering angle are calculated and produce good agreement with observational data. The major conclusions of our calculations are: – The original definition of A in Afρ is problematical and Afρ should be: qsca(n,λ)×p(g)×f×ρqsca(n,λ)×p(g)×f×ρ. Nevertheless, we keep the present nomenclature of Afρ as a measured quantity for an ensemble of coma particles.– The ratio between Afρ and the dust mass loss rate View the MathML sourcem˙ is dominated by the particle size distribution. – For most particle size distributions presently in use, small particles in the range from 0.10 to 1.0 μm contribute a large fraction to Afρ. – Simplifying the calculation of Afρ by considering only large particles and approximating qsca does not represent a realistic model. Mie scattering theory or if necessary, more complex scattering calculations must be used. – For the commonly used particle size distribution, dn/da ∼ a−3.5 to a−4, there is a natural cut off in Afρ contribution for both small and large particles. – The scattering phase function must be taken into account for each particle size; otherwise the contribution of large particles can be over-estimated by a factor of 10. – Using an imaginary index of refraction of i = 0.10 does not produce sufficient backscattering to match observational data. – A mixture of dark particles with i ⩾ 0.10 and brighter silicate particles with i ⩽ 0.04 matches the observed phase curves quite well. – Using current observational constraints, we find the dust/gas mass-production ratio of CG at 1.3 AU is confined to a range of 0.03–0.5 with a reasonably likely value around 0.1.

Observation of a new type of low-frequency waves at comet 67P/Churyumov-Gerasimenko

We report on magnetic field measurements made in the innermost coma of 67P/Churyumov-Gerasimenko in its low-activity state. Quasi-coherent, large-amplitude (δ B/B ~ 1), compressional magnetic field oscillations at ~ 40 mHz dominate the immediate plasma environment of the nucleus. This differs from previously studied cometary interaction regions where waves at the cometary ion gyro-frequencies are the main feature. Thus classical pickup-ion-driven instabilities are unable to explain the observations. We propose a cross-field current instability associated with newborn cometary ion currents as a possible source mechanism.

Inventory of the volatiles on comet 67P/Churyumov-Gerasimenko from Rosetta/ROSINA

Context. The ESA Rosetta spacecraft (S/C) is tracking comet 67P/Churyumov-Gerasimenko in close vicinity. This prolonged encounter enables studying the evolution of the volatile coma composition. Aims. Our work aims at comparing the diversity of the coma of 67P/Churyumov-Gerasimenko at large heliocentric distance to study the evolution of the comet during its passage around the Sun and at trying to classify it relative to other comets. Methods. We used the Double Focussing Mass Spectrometer (DFMS) of the ROSINA experiment on ESA’s Rosetta mission to determine relative abundances of major and minor volatile species. This study is restricted to species that have previously been detected elsewhere. Results. We detect almost all species currently known to be present in cometary coma with ROSINA DFMS. As DFMS measured the composition locally, we cannot derive a global abundance, but we compare measurements from the summer and the winter hemisphere with known abundances from other comets. Differences between relative abundances between summer and winter hemispheres are large, which points to a possible evolution of the cometary surface. This comet appears to be very rich in CO2 and ethane. Heavy oxygenated compounds such as ethylene glycol are underabundant at 3 AU, probably due to their high sublimation temperatures, but nevertheless, their presence proves that Kuiper belt comets also contain complex organic molecules.

Molecular oxygen in oort cloud comet 1P/Halley

Recently, the ROSINA mass spectrometer suite on board the European Space Agency's Rosetta spacecraft discovered an abundant amount of molecular oxygen, O2, in the coma of Jupiter family comet 67P/Churyumov-Gerasimenko of O2/H2O = 3.80 ± 0.85%. It could be shown that O2 is indeed a parent species and that the derived abundances point to a primordial origin. Crucial questions are whether the O2 abundance is peculiar to comet 67P/Churyumov-Gerasimenko or Jupiter family comets in general, and also whether Oort cloud comets such as comet 1P/Halley contain similar amounts of molecular oxygen. We investigated mass spectra obtained by the Neutral Mass Spectrometer instrument during the flyby by the European Space Agency's Giotto probe of comet 1P/Halley. Our investigation indicates that a production rate of O2 of 3.7 ± 1.7% with respect to water is indeed compatible with the obtained Halley data and therefore that O2 might be a rather common and abundant parent species.

Modeled Interaction of Comet 67P/Churyumov-Gerasimenko with the Solar Wind Inside 2 AU

Periodic comets move around the Sun on elliptical orbits. As such comet 67P/Churyumov-Gerasimenko (hereafter 67P) spends a portion of time in the inner solar system where it is exposed to increased solar insolation. Therefore given the change in heliocentric distance, in case of 67P from aphelion at 5.68 AU to perihelion at ~1.24 AU, the comet’s activity—the production of neutral gas and dust—undergoes significant variations. As a consequence, during the inbound portion, the mass loading of the solar wind increases and extends to larger spatial scales. This paper investigates how this interaction changes the character of the plasma environment of the comet by means of multifluid MHD simulations. The multifluid MHD model is capable of separating the dynamics of the solar wind ions and the pick-up ions created through photoionization and electron impact ionization in the coma of the comet. We show how two of the major boundaries, the bow shock and the diamagnetic cavity, form and develop as the comet moves through the inner solar system. Likewise for 67P, although most likely shifted back in time with respect to perihelion passage, this process is reversed on the outbound portion of the orbit. The presented model herein is able to reproduce some of the key features previously only accessible to particle-based models that take full account of the ions’ gyration. The results shown herein are in decent agreement to these hybrid-type kinetic simulations.

Composition-dependent outgassing of comet 67P/Churyumov-Gerasimenko from ROSINA/DFMS

Context. Early measurements of Rosetta’s target comet, 67P/Churyumov-Gerasimenko (67P), showed a strongly heterogeneous coma in H2O, CO, and CO2. Aims. The purpose of this work is to further investigate the coma heterogeneity of 67P, and to provide predictions for the near-perihelion outgassing profile based on the proposed explanations. Methods. Measurements of various minor volatile species by ROSINA/DFMS on board Rosetta are examined. The analysis focuses on the currently poorly illuminated winter (southern) hemisphere of 67P. Results. Coma heterogeneity is not limited to the major outgassing species. Minor species show better correlation with either H2O or CO2. The molecule CH4 shows a different diurnal pattern from all other analyzed species. Such features have implications for nucleus heterogeneity and thermal processing. Conclusions. Future analysis of additional volatiles and modeling the heterogeneity are required to better understand the observed coma profile.

Is surgery in aCute aortiC disseCtion type A still ContraindiCated in the presenCe of preoperative neurologiCal symptoms?

Gebiet: Kardiologie Abstract: OBJECTIVES: Severe neurologiCal defiCit (ND) due to aCute aortiC disseCtion type A (AADA) was Considered a ContraindiCation for surgery beCause of poor prognosis. ReCently, more aggressive indiCation for surgery despite neurologiCal symptoms has shown aCCeptable – postoperative CliniCal results. The aim of this study was to evaluate early and mid-term outComes of patients with AADA presenting with aCute ND. – – METHODS: Data from 53 patients with new-onset ND who reCeived surgiCal repair for AADA between 2005 and 2012 at our institution were retrospeCtively reviewed. ND was defined as foCal motor or sensory defiCit, hemiplegia, paraplegia, Convulsions or Coma. NeurologiCal symptoms were evaluated preoperatively using the Glasgow Coma SCale (GCS) and modified Rankin SCale (mRS), and at disCharge as well as 3–6 months postoperatively using the mRS and National Institutes of Health Stroke SCale. Involvement of Carotid arteries was assessed in the pre- and postoperative Computed tomography. LogistiC regression analysis was performed to deteCt prediCtive faCtors for reCovery of ND. – – RESULTS: Of the 53 patients, 29 (54.7%) showed Complete reCovery from foCal ND at follow-up. NeurologiCal symptoms persisted in 24 (45.3%) patients, of whiCh 8 (33%) died without neurologiCal assessment at follow-up. Between the two groups (patients with reCovery and – those with persisting ND), there was no signifiCant differenCe regarding the duration of hypothermiC CirCulatory arrest (28 ± 14 vs 36 ± 20 min) or severely reduCed ConsCiousness (GCS <8). Multivariate analysis showed signifiCant differenCes for the preoperative mRS between the two groups (P < 0.007). A high preoperative mRS was assoCiated with persistenCe of neurologiCal symptoms (P < 0.02). CardiovasCular risk faCtors, age or involvement of supra-aortiC branChes were not prediCtive for persistenCe of ND. – – CONCLUSION: More than half of our patients reCovered Completely from ND due to AADA after surgery. Severity of CliniCal symptoms had a prediCtive value. Patients suffering from AADA and presenting with ND before surgery should not be exCluded from emergenCy surgery.

Risk of severe hypoglycemia in sulfonylurea-treated patients from diabetes centers in Germany/Austria: how big is the problem? which patients are at risk?

BACKGROUND We investigated the rate of severe hypoglycemic events and confounding factors in patients with type-2-diabetes treated with sulfonylurea (SU) at specialized diabetes centers, documented in the German/Austrian DPV-Wiss-database. METHODS Data from 29,485 SU-treated patients were analyzed (median[IQR] age 70.8[62.2-77.8]yrs, diabetes-duration 8.2[4.3-12.8]yrs). The primary objective was to estimate the event-rate of severe hypoglycemia (requiring external help, causing unconsciousness/coma/convulsion and/or emergency.hospitalization). Secondary objectives included exploration of confounding risk-factors through group-comparison and Poisson-regression. RESULTS Severe hypoglycemic events were reported in 826(2.8%) of all patients during their most recent year of SU-treatment. Of these, n = 531(1.8%) had coma, n = 501(1.7%) were hospitalized at least once. The adjusted event-rate of severe hypoglycemia [95%CI] was 3.9[3.7-4.2] events/100 patient-years (coma: 1.9[1.8-2.1]; hospitalization: 1.6[1.5-1.8]). Adjusted event-rates by diabetes-treatment were 6.7 (SU + insulin), 4.9 (SU + insulin + other OAD), 3.1 (SU + other OAD), and 3.8 (SU only). Patients with ≥1 severe event were older (p < 0.001) and had longer diabetes-duration (p = 0.020) than patients without severe events. Participation in educational diabetes-programs and indirect measures of insulin-resistance (increased BMI, plasma-triglycerides) were associated with fewer events (all p < 0.001). Impaired renal function was common (N = 3,113 eGFR ≤30 mL/min) and associated with an increased rate of severe events (≤30 mL/min: 7.7; 30-60 mL/min: 4.8; >60 mL/min: 3.9). CONCLUSIONS These real-life data showed a rate of severe hypoglycemia of 3.9/100 patient-years in SU-treated patients from specialized diabetes centers. Higher risk was associated with known risk-factors including lack of diabetes-education, older age, and decreased eGFR, but also with lower BMI and lower triglyceride-levels, suggesting that SU-treatment in those patients should be considered with caution. This article is protected by copyright. All rights reserved.

Cohort Study on the Association Between Helmet Use and Traumatic Brain Injury in Snowboarders From a Swiss Tertiary Trauma Center.

BACKGROUND Since the introduction of helmets in winter sports there is on-going debate on whether they decrease traumatic brain injuries (TBI). METHODS This cohort study included 117 adult (≥ 16 years) snowboarders with TBI admitted to a level I alpine trauma center in Switzerland between 2000/2001 and 2010/2011. The primary objective was to examine the association between helmet use and moderate-to-severe TBI. Secondary objectives were to describe the epidemiology of TBI during the past decade in relation to increased helmet use. RESULTS Of 691 injured snowboarders evaluated, 117 (17%) suffered TBI. Sixty-six percent were men (median age, 23 years). Two percent of accidents were fatal. Ninety-two percent of patients sustained minor, 1% moderate, and 7% severe TBI according to the Glasgow coma scale. Pathologic computed tomography findings were present in 16% of patients, 26% of which required surgery. Eighty-three percent of TBIs occurred while riding on-slope. There was no trend in the TBI rate during the studied period, although helmet use increased from 10% to 69%. Comparing patients with and without a helmet showed no significant difference in odds ratios for the severity of TBI. However, of the 5 patients requiring surgery only 1 was wearing a helmet. Off-piste compared with on-slope snowboarders showed an odds ratio of 26.5 (P = 0.003) for sustaining a moderate-to-severe TBI. CONCLUSIONS Despite increased helmet use we found no decrease in TBI among snowboarders. The possibility of TBI despite helmet use and the dangers of riding off-piste should be a focus of future prevention programs.