Systemic-to-Pulmonary Artery Pressure Ratio as a Predictor of Patient Outcome Following Liver Transplantation

AIM To assess the value of the mean systemic-to-pulmonary artery pressure (MAP/mPAP) ratio for predicting outcomes following orthotopic liver transplant (OLT). METHODS A retrospective data analysis was performed and data (mean arterial blood pressure, mean pulmonary artery pressure and Cardiac Index) were collected at several points during OLT. Outcomes evaluated were duration of postoperative endotracheal intubation [ET; minutes after intensive care unit (ICU) arrival], length of ICU stay, total hospitalization and frequency of immediate postoperative complications. A total of 91 patients were included in the data analysis. Based on the intraoperative course of the MAP/mPAP ratio, 2 hemodynamic responses were identified: Group 1 (MAP/mPAP ratio increase during anhepatic period with postreperfusion recovery, n = 66); and Group 2 (MAP/mPAP ratio with no change during anhepatic period or decreased without recovery, n = 25). RESULTS The main finding was that the lack of increased MAP/mPAP ratio in the anhepatic period was associated with: (1) longer intubation times; and (2) prolonged ICU stays and total hospitalization time, when compared to patients with an increase in MAP/mPAP ratio during the anhepatic period. CONCLUSION The data from this retrospective study should raise awareness to the mean systemic to pulmonary artery pressure ratio as a potential indicator for poor outcome after OLT. Further prospective studies are needed for validation

On the metallicity dependence of crystalline silicates in oxygen-rich asymptotic giant branch stars and red supergiants

We investigate the occurrence of crystalline silicates in oxygen-rich evolved stars across a range of metallicities and mass-loss rates. It has been suggested that the crystalline silicate feature strength increases with increasing mass-loss rate, implying a correlation between lattice structure and wind density. To test this, we analyse Spitzer IRS and Infrared Space Observatory SWS spectra of 217 oxygen-rich asymptotic giant branch stars and 98 red supergiants in the Milky Way, the Large and Small Magellanic Clouds and Galactic globular clusters. These encompass a range of spectral morphologies from the spectrally-rich which exhibit a wealth of crystalline and amorphous silicate features to 'naked' (dust-free) stars. We combine spectroscopic and photometric observations with the GRAMS grid of radiative transfer models to derive (dust) mass-loss rates and temperature. We then measure the strength of the crystalline silicate bands at 23, 28 and 33 microns. We detect crystalline silicates in stars with dust mass-loss rates which span over 3 dex, down to rates of ~10^-9 solar masses/year. Detections of crystalline silicates are more prevalent in higher mass-loss rate objects, though the highest mass-loss rate objects do not show the 23-micron feature, possibly due to the low temperature of the forsterite grains or it may indicate that the 23-micron band is going into absorption due to high column density. Furthermore, we detect a change in the crystalline silicate mineralogy with metallicity, with enstatite seen increasingly at low metallicity.Comment: Accepted for publication in MNRAS, 24 pages, 16 figure

Cognitive Aid Use Improves Transition of Care by Graduating Medical Students During a Simulated Crisis

Background: Residents are expected to have transition of care (ToC) skills upon entering graduate medical education. It is unclear whether experience and training during medical school is adequate. Objective: The aim of the project was to assess: 1) graduating medical students\u27 ability to perform ToC in a crisis situation, and 2) whether using a cognitive aid improves the ToC quality. Methods: The authors developed simulation scenarios for rapid response teams and a cognitive aid to assist in the ToC during crisis situations. Graduating medical students were enrolled and randomly divided into teams of three students, randomly assigned into one of two groups: teams using a cognitive aid for ToC (CA), or not using a cognitive aid (nCA). In the scenario, teams respond to a deteriorating patient and then transfer care to the next provider after stabilization. Three faculty reviewed the recording to assess completeness of the ToC and the overall quality. A completeness score was expressed as a fraction of the maximum score. Statistical analysis was performed using a t-test and Mann-Whitney U test. Results: A total of 112 senior medical students participated: CA n=19, nCA n=17. The completeness score of the ToC and overall quality improved when using the cognitive aid (completeness score: CA 0.80±0.06 vs. nCA 0.52±0.07, p \u3c 0.01; ToC quality: CA 3.16±0.65 vs. nCA 1.92±0.56, p \u3c 0.01). Participants’ rating of knowledge and comfort with the ToC process increased after the simulation. Conclusion: The completeness of information transfer during the ToC process by graduating medical students improved by using a cognitive aid in a simulated patient crisis

The Spitzer discovery of a galaxy with infrared emission solely due to AGN activity

We present a galaxy (SAGE1CJ053634.78-722658.5) at a redshift of 0.14 of which the IR is entirely dominated by emission associated with the AGN. We present the 5-37 um Spitzer/IRS spectrum and broad wavelength SED of SAGE1CJ053634, an IR point-source detected by Spitzer/SAGE (Meixner et al 2006). The source was observed in the SAGE-Spec program (Kemper et al., 2010) and was included to determine the nature of sources with deviant IR colours. The spectrum shows a redshifted (z=0.14+-0.005) silicate emission feature with an exceptionally high feature-to-continuum ratio and weak polycyclic aromatic hydrocarbon (PAH) bands. We compare the source with models of emission from dusty tori around AGNs from Nenkova et al. (2008). We present a diagnostic diagram that will help to identify similar sources based on Spitzer/MIPS and Herschel/PACS photometry. The SED of SAGE1CJ053634 is peculiar because it lacks far-IR emission and a clear stellar counterpart. We find that the SED and the IR spectrum can be understood as emission originating from the inner ~10 pc around an accreting black hole. There is no need to invoke emission from the host galaxy, either from the stars or from the interstellar medium, although a possible early-type host galaxy cannot be excluded based on the SED analysis. The hot dust around the accretion disk gives rise to a continuum, which peaks at 4 um, whereas the strong silicate features may arise from optically thin emission of dusty clouds within ~10 pc around the black hole. The weak PAH emission does not appear to be linked to star formation, as star formation templates strongly over-predict the measured far-IR flux levels. The SED of SAGE1CJ053634 is rare in the local universe but may be more common in the more distant universe. The conspicuous absence of host-galaxy IR emission places limits on the far-IR emission arising from the dusty torus alone.Comment: Accepted for publication in A&A, 7 pages, 6 figure

Combining Survival and Toxicity Effect Sizes from Clinical Trials: NCCTG 89-20-52 (Alliance)

Background: How can a clinician and patient incorporate survival and toxicity information into a single expression of comparative treatment benefit? Sloan et al. recently extended the ½ standard deviation concept for judging the clinical importance of findings from clinical trials to survival and tumor response endpoints. A new method using this approach to combine survival and toxicity effect sizes from clinical trials into a quality-adjusted effect size is presented.Methods: The quality-adjusted survival effect size (QASES) is calculated as survival effect size (ESS) minus the calibrated toxicity effect sizes (EST) (QASES=ESS-EST). This combined effect size can be weighted to adjust for the relative emphasis placed by the patient on survival and toxicity effects.Results: As an example, consider clinical trial NCCTG 89-20-52 which randomized patients to once-daily thoracic radiotherapy (ODTRT) versus twice-daily treatment of thoracic radiotherapy (TDRT) for the treatment of lung cancer. The ODTRT vs. TDRT arms had median survival time of 22 vs. 20 months (p=0.49) and toxicity rate of 39% vs. 54%, (p<0.05). The QASES of 0.18 standard deviations translates to a quality-adjusted survival difference of 5.7 months advantage for the ODRT arm over the TDRT treatment arm (22(16.3) months), p<0.05). Similar results are presented for the four possible case combinations of significant/non-significant survival and toxicity benefits using completed clinical trials.Conclusions: We used a novel approach to re-analyze clinical trial data to produce a single estimate for each treatment that combines survival and toxicity data. The QASES approach is an intuitive and mathematically simple yet robust approach

Ice chemistry in massive Young Stellar Objects: the role of metallicity

We present the comparison of the three most important ice constituents (water, CO and CO2) in the envelopes of massive Young Stellar Objects (YSOs), in environments of different metallicities: the Galaxy, the Large Magellanic Cloud (LMC) and, for the first time, the Small Magellanic Cloud (SMC). We present observations of water, CO and CO2 ice in 4 SMC and 3 LMC YSOs (obtained with Spitzer-IRS and VLT/ISAAC). While water and CO2 ice are detected in all Magellanic YSOs, CO ice is not detected in the SMC objects. Both CO and CO2 ice abundances are enhanced in the LMC when compared to high-luminosity Galactic YSOs. Based on the fact that both species appear to be enhanced in a consistent way, this effect is unlikely to be the result of enhanced CO2 production in hotter YSO envelopes as previously thought. Instead we propose that this results from a reduced water column density in the envelopes of LMC YSOs, a direct consequence of both the stronger UV radiation field and the reduced dust-to-gas ratio at lower metallicity. In the SMC the environmental conditions are harsher, and we observe a reduction in CO2 column density. Furthermore, the low gas-phase CO density and higher dust temperature in YSO envelopes in the SMC seem to inhibit CO freeze-out. The scenario we propose can be tested with further observations.Comment: accepted by MNRAS Letters; 5 pages, 3 figures, 1 tabl