Impact of bedside open lung biopsies on the management of mechanically ventilated immunocompromised patients with acute respiratory distress syndrome of unknown etiology.

BACKGROUND: Open lung biopsy (OLB) is helpful in the management of patients with acute respiratory distress syndrome (ARDS) of unknown etiology. We determine the impact of surgical lung biopsies performed at the bedside on the management of patients with ARDS. METHODS: We reviewed all consecutive cases of patients with ARDS who underwent a surgical OLB at the bedside in a medical intensive care unit between 1993 and 2005. RESULTS: Biopsies were performed in 19 patients mechanically ventilated for ARDS of unknown etiology despite extensive diagnostic process and empirical therapeutic trials. Among them, 17 (89%) were immunocompromised and 10 patients experienced hematological malignancies. Surgical biopsies were obtained after a median (25%-75%) mechanical ventilation of 5 (2-11) days; mean (+/-SD) Pao(2)/Fio(2) ratio was 119.3 (+/-34.2) mm Hg. Histologic diagnoses were obtained in all cases and were specific in 13 patients (68%), including 9 (47%) not previously suspected. Immediate complications (26%) were local (pneumothorax, minimal bleeding) without general or respiratory consequences. The biopsy resulted in major changes in management in 17 patients (89%). It contributed to a decision to limit care in 12 of 17 patients who died. CONCLUSION: Our data confirm that surgical OLB may have an important impact on the management of patients with ARDS of unknown etiology after extensive diagnostic process. The procedure can be performed at the bedside, is safe, and has a high diagnostic yield leading to major changes in management, including withdrawal of vital support, in the majority of patients.

Safety and accuracy of robot-assisted versus fluoroscopy-guided pedicle screw insertion for degenerative diseases of the lumbar spine: a matched cohort comparison.

Object Recent years have been marked by efforts to improve the quality and safety of pedicle screw placement in spinal instrumentation. The aim of the present study is to compare the accuracy of the SpineAssist robot system with conventional fluoroscopy-guided pedicle screw placement. Methods Ninety-five patients suffering from degenerative disease and requiring elective lumbar instrumentation were included in the study. The robot cohort (Group I; 55 patients, 244 screws) consisted of an initial open robot-assisted subgroup (Subgroup IA; 17 patients, 83 screws) and a percutaneous cohort (Subgroup IB, 38 patients, 161 screws). In these groups, pedicle screws were placed under robotic guidance and lateral fluoroscopic control. In the fluoroscopy-guided cohort (Group II; 40 patients, 163 screws) screws were inserted using anatomical landmarks and lateral fluoroscopic guidance. The primary outcome measure was accuracy of screw placement on the Gertzbein-Robbins scale (Grade A to E and R [revised]). Secondary parameters were duration of surgery, blood loss, cumulative morphine, and length of stay. Results In the robot group (Group I), a perfect trajectory (A) was observed in 204 screws (83.6%). The remaining screws were graded B (n = 19 [7.8%]), C (n = 9 [3.7%]), D (n = 4 [1.6%]), E (n = 2 [0.8%]), and R (n = 6 [2.5%]). In the fluoroscopy-guided group (Group II), a completely intrapedicular course graded A was found in 79.8% (n = 130). The remaining screws were graded B (n = 12 [7.4%]), C (n = 10 [6.1%]), D (n = 6 [3.7%]), and E (n = 5 [3.1%]). The comparison of "clinically acceptable" (that is, A and B screws) was neither different between groups (I vs II [p = 0.19]) nor subgroups (Subgroup IA vs IB [p = 0.81]; Subgroup IA vs Group II [p = 0.53]; Subgroup IB vs Group II [p = 0.20]). Blood loss was lower in the robot-assisted group than in the fluoroscopy-guided group, while duration of surgery, length of stay, and cumulative morphine dose were not statistically different. Conclusions Robot-guided pedicle screw placement is a safe and useful tool for assisting spine surgeons in degenerative spine cases. Nonetheless, technical difficulties remain and fluoroscopy backup is advocated.

Microquasars as high energy gamma-ray sources

Galactic microquasars are certainly one of the most recent additions to the field of high energy astrophysics and have attracted increasing interest over the last decade. However, the high energy part of the spectrum of microquasars is the most poorly known, mainly due the lack of sensitive instrumentation in the past. Microquasars are now primary targets for all of the observatories working in the X-ray and gamma-ray domains. They also appear as the possible counterparts for some of the unidentified sources of high-energy gamma-rays detected by the experiment EGRET on board the satellite COMPTON-GRO. This paper provides a general review of the main observational results obtained up to now as well as a summary of the scenarios for production of high-energy gamma-rays at the present moment.

High-performance payload data handling system for Gaia

Gaia is the most ambitious space astrometry mission currently envisaged and is a technological challenge in all its aspects. We describe a proposal for the payload data handling system of Gaia, as an example of a high-performance, real-time, concurrent, and pipelined data system. This proposal includes the front-end systems for the instrumentation, the data acquisition and management modules, the star data processing modules, and the payload data handling unit. We also review other payload and service module elements and we illustrate a data flux proposal.

Mise en place d'un cathéter veineux central chez l'adulte. 1. Indications, précautions et complications [Bases of central venous catheterization]

La pose d'un cathéter veineux central est un geste fréquent dans un service de médecine interne. En suivant la formation des médecins-assistants, nous nous sommes aperçus que certaines questions, doutes ou craintes concernant cette procédure nous sont régulièrement adressées: «Est-ce qu'un cathéter sous-clavier peut être posé avec une thrombocytopénie modérée?»; «Quel site de ponction présente le moins de risques pour le patient?»; «Après combien de jours un cathéter doit-il être changé?». Cet article se propose de répondre à ces questions et à d'autres, en partant d'une mini-revue de la littérature actuelle. Central venous catheterization is a frequently performed procedure in internal medicine units. Residents in training frequently share the same questions, doubts and fears about this procedure : "Should I perform a subclavian catheterization in a patient with mild thrombopenia?"; "Which site has the lesser complication rate?"; "After how long does a catheter need to be replaced?". This mini-review of the current literature tries to answer this and other questions

Three-dimensional ordered-subset expectation maximization iterative protocol for evaluation of left ventricular volumes and function by quantitative gated SPECT: a dynamic phantom study.

The purposes of this study were to characterize the performance of a 3-dimensional (3D) ordered-subset expectation maximization (OSEM) algorithm in the quantification of left ventricular (LV) function with (99m)Tc-labeled agent gated SPECT (G-SPECT), the QGS program, and a beating-heart phantom and to optimize the reconstruction parameters for clinical applications. METHODS: A G-SPECT image of a dynamic heart phantom simulating the beating left ventricle was acquired. The exact volumes of the phantom were known and were as follows: end-diastolic volume (EDV) of 112 mL, end-systolic volume (ESV) of 37 mL, and stroke volume (SV) of 75 mL; these volumes produced an LV ejection fraction (LVEF) of 67%. Tomographic reconstructions were obtained after 10-20 iterations (I) with 4, 8, and 16 subsets (S) at full width at half maximum (FWHM) gaussian postprocessing filter cutoff values of 8-15 mm. The QGS program was used for quantitative measurements. RESULTS: Measured values ranged from 72 to 92 mL for EDV, from 18 to 32 mL for ESV, and from 54 to 63 mL for SV, and the calculated LVEF ranged from 65% to 76%. Overall, the combination of 10 I, 8 S, and a cutoff filter value of 10 mm produced the most accurate results. The plot of the measures with respect to the expectation maximization-equivalent iterations (I x S product) revealed a bell-shaped curve for the LV volumes and a reverse distribution for the LVEF, with the best results in the intermediate range. In particular, FWHM cutoff values exceeding 10 mm affected the estimation of the LV volumes. CONCLUSION: The QGS program is able to correctly calculate the LVEF when used in association with an optimized 3D OSEM algorithm (8 S, 10 I, and FWHM of 10 mm) but underestimates the LV volumes. However, various combinations of technical parameters, including a limited range of I and S (80-160 expectation maximization-equivalent iterations) and low cutoff values (< or =10 mm) for the gaussian postprocessing filter, produced results with similar accuracies and without clinically relevant differences in the LV volumes and the estimated LVEF.

Analyse de l'activité de match chez l'arbitre de football par accéléromètre et critique des tests de sélection FIFA

Introduction : Depuis 2005, le « Test FIFA » est utilisé chez les arbitres de football, comme critère de sélection pour monter dans les échelons de l'arbitrage et chaque arbitre base son entraînement dans cet objectif. Ce test a été développé grâce aux nombreux travaux scientifiques, ayant utilisé l'analyse vidéo, afin de quantifier les activités de match des arbitres et analyser leur performance en cours de match. Objectifs : Le but de ce travail a été d'évaluer la performance de l'arbitre, lors d'un match de football, au moyen d'un accéléromètre en raison de sa facilité d'utilisation et en particulier d'évaluer si au cours du match, il existe une éventuelle diminution de la capacité de performance engendrée par la fatigue. Enfin, à la lumière des résultats, nous avons pu discuter du bien fondé du «test par intervalle proposé par la FIFA» comme moyen d'estimation de la capacité physique d'un arbitre. Méthode : Il s'agit d'une étude prospective basée sur une analyse descriptive. Les données ont été récoltées dans des stades de football suisses ≥1ère Ligue, du 01.12.2011 au 01.12.2012. Le groupe étudié était composé de 5 arbitres de football de sexe masculin, dont deux officiant en 1ère Ligue et faisant partie des talents de l'Association Cantonale Vaudoise de Football (ACVF) et trois en Super League et Challenge League. Les 5 arbitres ont été équipés d'un iPhone 3GS®, muni d'une application, capable d'enregistrer les déplacements sur le terrain (arrêt, marche et course). Le traitement des données a été effectué par un programme Matlab®, élaboré par le Laboratoire des Mesures d'Analyse du Mouvement (LMAM) de l'EPFL, tout comme l'application en question. Pour ce travail ont été considérées les phases et les fréquences d'arrêt, de marche et de course tout au long de l'évolution de la partie. Résultats : Durant les 90 minutes du match, la répartition se fait de la manière suivante : 13,74% du temps total où l'accéléromètre ne mesure aucune activité, 33,70% concernent une activité de course alors que le reste, 52,48% est de la marche. Avec l'avancement dans le match, il est constaté une augmentation des phases d'arrêt et une diminution du temps de course. Une intensité d'effort plus importante est observée lors des 15 premières minutes du match (environ  41,7% de course), alors qu'en fin de la partie, il y a une alternance de marche et de course avec des efforts de plus en plus brefs. La détermination de la médiane de durée des différents efforts a montré qu'un épisode de marche ou de course étaient de 5-6 secondes. De plus, les épisodes de marche ou de course étaient rarement >20 secondes. Discussion : Les résultats montrent que l'accéléromètre est un système de mesure facile d'utilisation, permettant un gain de temps dans l'analyse des données pour évaluer la performance sportive. Les principaux résultats de cette étude, ont mis en évidence une diminution de l'intensité des activités physiques de l'arbitre avec l'avancement du match, résultant soit de sa propre fatigue, soit de celle des joueurs dictant le rythme du jeu. Cette diminution se traduit par des déplacements de plus en plus brefs au fil du temps. La mesure de médiane du temps de course et de marche (5-6 sec) correspond à une activité aérobie pour la marche et anaérobie alactique pour la course. Par conséquent, le « test par intervalle » de la FIFA actuel ne nous semble pas adéquat en raison de sa filière énergétique de type anaérobique lactique. Conclusion : Cette étude pilote apporte un nouveau type d'instrumentation efficace et simple, jamais employé auparavant dans l'analyse des activités de match des arbitres de football. Il permet d'explorer des mouvements avec précision au fil du match et apporte un nouvel aspect sur la quantification de performance des arbitres non exploré jusqu'ici. Après analyse de l'ensemble des paramètres, il semble que le test FIFA ne soit pas adapté à la performance exigée par l'arbitrage.

Activity measurements of 18F and 90Y with commercial radionuclide calibrators for nuclear medicine in Switzerland.

The activity of radiopharmaceuticals in nuclear medicine is measured before patient injection with radionuclide calibrators. In Switzerland, the general requirements for quality controls are defined in a federal ordinance and a directive of the Federal Office of Metrology (METAS) which require each instrument to be verified. A set of three gamma sources (Co-57, Cs-137 and Co-60) is used to verify the response of radionuclide calibrators in the gamma energy range of their use. A beta source, a mixture of (90)Sr and (90)Y in secular equilibrium, is used as well. Manufacturers are responsible for the calibration factors. The main goal of the study was to monitor the validity of the calibration factors by using two sources: a (90)Sr/(90)Y source and a (18)F source. The three types of commercial radionuclide calibrators tested do not have a calibration factor for the mixture but only for (90)Y. Activity measurements of a (90)Sr/(90)Y source with the (90)Y calibration factor are performed in order to correct for the extra-contribution of (90)Sr. The value of the correction factor was found to be 1.113 whereas Monte Carlo simulations of the radionuclide calibrators estimate the correction factor to be 1.117. Measurements with (18)F sources in a specific geometry are also performed. Since this radionuclide is widely used in Swiss hospitals equipped with PET and PET-CT, the metrology of the (18)F is very important. The (18)F response normalized to the (137)Cs response shows that the difference with a reference value does not exceed 3% for the three types of radionuclide calibrators.

Bilateral extraperitoneal uterosacral vaginal vault suspension: a 2-year follow-up longitudinal case series of 123 patients.

INTRODUCTION AND HYPOTHESIS: The objective of this study is to assess anatomical and functional results of the extraperitoneal uterosacral ligament suspension (USL) in women with post-hysterectomy vaginal vault prolapse. METHODS: One hundred and twenty-three consecutive women were included. Concurrent procedures were anterior colporraphy with fascial repair (20%) and mesh reinforcement (49%), posterior colporraphy with fascial repair (38%) and mesh reinforcement (56%) and a sling procedure (29%). Women were assessed using Baden and Walker and pelvic organ prolapse quantification classification pre- and post-operatively. RESULTS: One hundred and ten patients (89%) were available for follow-up. Mean follow-up was 2 years. Objective success rate regarding the vaginal cuff is 95.4%. Global anatomical success rate was 85.5%. Urinary, coital and bowel symptoms were improved following surgery. Mesh exposure rate was 19.3%, with all cases managed conservatively or with minor interventions. CONCLUSION: Bilateral extraperitoneal USL is an effective operation to restore apical support with low morbidity, which avoids potential risks associated with opening the peritoneal cavity.

Stent-assisted coiling of bifurcation aneurysms may improve endovascular treatment: a critical evaluation in an experimental model.

BACKGROUND AND PURPOSE: Endovascular treatment of wide-neck bifurcation aneurysms often results in incomplete occlusion or aneurysm recurrence. The goals of this study were to compare results of coil embolization with or without the assistance of self-expandable stents and to examine how stents may influence neointima formation. MATERIALS AND METHODS: Wide-neck bifurcation aneurysms were constructed in 24 animals and, after 4-6 weeks, were randomly allocated to 1 of 5 groups: 1) coil embolization using the assistance of 1 braided stent (n = 5); 2) coil embolization using the assistance of 2 braided stents in a Y configuration (n = 5); 3) coil embolization without stent assistance (n = 6); 4) Y-stenting alone (n = 4); and 5) untreated controls (n = 4). Angiographic results were compared at baseline and at 12 weeks, by using an ordinal scale. Neointima formation at the neck at 12 weeks was compared among groups by using a semiquantitative grading scale. Bench studies were performed to assess stent porosities. RESULTS: Initial angiographic results were improved with single stent-assisted coiling compared with simple coiling (P = .013). Angiographic results at 12 weeks were improved with any stent assistance (P = .014). Neointimal closure of the aneurysm neck was similar with or without stent assistance (P = .908), with neointima covering coil loops but rarely stent struts. Y-stent placement alone had no therapeutic effect. Bench studies showed that porosities can be decreased with stent compaction, but a relatively stable porous transition zone was a limiting factor. CONCLUSIONS: Stent-assisted coiling may improve results of embolization by allowing more complete initial coiling, but these high-porosity stents did not provide a scaffold for more complete neointimal closure of aneurysms.

Electrophysiological recording from Drosophila taste sensilla.

INTRODUCTION The chemical senses smell and taste, detect and discriminate an enormous diversity of environmental stimuli and provide fascinating but challenging models to investigate how sensory cues are represented in the brain. Important stimulus-coding events occur in peripheral sensory neurons, which express specific combinations of chemosensory receptors with defined ligand-response profiles. These receptors convert ligand recognition into spatial and temporal patterns of neural activity that are transmitted to and interpreted in central brain regions. Drosophila provides an attractive model to study chemosensory coding, because it possesses relatively simple peripheral olfactory and gustatory systems that display many organizational parallels to those of vertebrates. Moreover, virtually all of the peripheral chemosensory neurons are easily accessible for physiological analysis, as they are exposed on the surface of sensory organs in specialized sensory hairs called sensilla. In recent years, improvements in microscopy and instrumentation for electrode manipulation have opened up the much smaller Drosophila system to electrophysiological techniques, powerfully complementing many years of molecular genetic studies. As with most electrophysiological methods, there is probably no substitute for learning this technique directly from a laboratory in which it is already established. This protocol describes the basics of setting up the electrophysiology rig and stimulus delivery device, sample preparation, and performing and analyzing recordings of stimulus-evoked activity from Drosophila taste sensilla.

Validity of an arterial pressure waveform analysis device: does the puncture site play a role in the agreement with intermittent pulmonary artery catheter thermodilution measurements?

OBJECTIVE: The measurement of cardiac output is a key element in the assessment of cardiac function. Recently, a pulse contour analysis-based device without need for calibration became available (FloTrac/Vigileo, Edwards Lifescience, Irvine, CA). This study was conducted to determine if there is an impact of the arterial catheter site and to investigate the accuracy of this system when compared with the pulmonary artery catheter using the bolus thermodilution technique (PAC). DESIGN: Prospective study. SETTING: The operating room of 1 university hospital. PARTICIPANTS: Twenty patients undergoing cardiac surgery. INTERVENTIONS: CO was determined in parallel by the use of the Flotrac/Vigileo systems in the radial and femoral position (CO_rad and CO_fem) and by PAC as the reference method. Data triplets were recorded at defined time points. The primary endpoint was the comparison of CO_rad and CO_fem, and the secondary endpoint was the comparison with the PAC. MEASUREMENTS AND MAIN RESULTS: Seventy-eight simultaneous data recordings were obtained. The Bland-Altman analysis for CO_fem and CO_rad showed a bias of 0.46 L/min, precision was 0.85 L/min, and the percentage error was 34%. The Bland-Altman analysis for CO_rad and PAC showed a bias of -0.35 L/min, the precision was 1.88 L/min, and the percentage error was 76%. The Bland-Altman analysis for CO_fem and PAC showed a bias of 0.11 L/min, the precision was 1.8 L/min, and the percentage error was 69%. CONCLUSION: The FloTrac/Vigileo system was shown to not produce exactly the same CO data when used in radial and femoral arteries, even though the percentage error was close to the clinically acceptable range. Thus, the impact of the introduction site of the arterial catheter is not negligible. The agreement with thermodilution was low.

Development of a microfluidics biosensor for agarose-bead immobilized Escherichia coli bioreporter cells for arsenite detection in aqueous samples.

Contamination with arsenic is a recurring problem in both industrialized and developing countries. Drinking water supplies for large populations can have concentrations much higher than the permissible levels (for most European countries and the United States, 10 μg As per L; elsewhere, 50 μg As per L). Arsenic analysis requires high-end instruments, which are largely unavailable in developing countries. Bioassays based on genetically engineered bacteria have been proposed as suitable alternatives but such tests would profit from better standardization and direct incorporation into sensing devices. The goal of this work was to develop and test microfluidic devices in which bacterial bioreporters could be embedded, exposed and reporter signals detected, as a further step towards a complete miniaturized bacterial biosensor. The signal element in the biosensor is a nonpathogenic laboratory strain of Escherichia coli, which produces a variant of the green fluorescent protein after contact to arsenite and arsenate. E. coli bioreporter cells were encapsulated in agarose beads and incorporated into a microfluidic device where they were captured in 500 × 500 μm(2) cages and exposed to aqueous samples containing arsenic. Cell-beads frozen at -20 °C in the microfluidic chip retained inducibility for up to a month and arsenic samples with 10 or 50 μg L(-1) could be reproducibly discriminated from the blank. In the 0-50 μg L(-1) range and with an exposure time of 200 minutes, the rate of signal increase was linearly proportional to the arsenic concentration. The time needed to reliably and reproducibly detect a concentration of 50 μg L(-1) was 75-120 minutes, and 120-180 minutes for a concentration of 10 μg L(-1).

Coronary artery imaging by magnetic resonance.

Non-invasive visualization of the coronary arteries represents a major challenge in modern cardiology, but this goal may be achieved in the near future by MR angiography. Possible applications are non-invasive diagnosis of coronary artery disease, and follow-up examinations for therapy control after PTCA, in order to detect restenosis at an early stage. A multiple slice technique (2 mm slice thickness, with a spatial resolution of 1 x 1 mm, Philips Gyroscan ACS-II, 1.5 Tesla) was used. Ten volunteers were imaged and 10 patients with coronary artery disease were examined before and after PTCA. MR measurements were validated by quantitative coronary angiography. The diameters of the proximal coronary arteries as measured by both methods were compared, and a good correlation was found (r = 0.76). Thus, it is concluded that non-invasive visualization of the coronary arteries is possible before and after PTCA and allows to determine potential restenoses. However, patient cooperation is essential for good image quality. Moreover, limited spatial image resolution and breathing artifacts restrict MR coronary angiography today to be used as a routine diagnostic tool for the diagnosis of coronary artery disease.