Structure and dynamics of topological defects in a glassy liquid on a negatively curved manifold

We study the low-temperature regime of an atomic liquid on the hyperbolic plane by means of molecular dynamics simulation and we compare the results to a continuum theory of defects in a negatively curved hexagonal background. In agreement with the theory and previous results on positively curved (spherical) surfaces, we find that the atomic configurations consist of isolated defect structures, dubbed "grain boundary scars", that form around an irreducible density of curvature-induced disclinations in an otherwise hexagonal background. We investigate the structure and the dynamics of these grain boundary scars

Pseudomonas aeruginosa acquisition on an intensive care unit: relationship between antibiotic selective pressure and patients' environment

International audienceABSTRACT: INTRODUCTION: To investigate the relationship between Pseudomonas aeruginosa acquisition on the intensive care unit (ICU), environmental contamination and antibiotic selective pressure against P. aeruginosa. METHODS: An open, prospective cohort study was carried out in a 16-bed medical ICU where P. aeruginosa was endemic. Over a 6-month period, all patients without P. aeruginosa on admission and with a length of stay >72 h were included. Throat, nasal, rectal, sputum and urine samples were taken on admission and at weekly intervals and screened for P. aeruginosa. All antibiotic treatments were recorded daily. Environmental analysis included weekly tap water specimen culture and presence of other patients colonized with P. aeruginosa. RESULTS: One-hundred and twenty-six patients were included, comprising 1345 patient-days. Antibiotics were given to 106 patients (antibiotic selective pressure for P. aeruginosa in 39). P. aeruginosa was acquired by 20 patients (16%) and was isolated from 164/536 environmental samples (31%). Two conditions were independently associated with P. aeruginosa acquisition by multivariate analysis: (i) patients receiving [greater than or equal to]3 days of antibiotic selective pressure together with at least one colonized patient on the same ward on the previous day (OR=10.3 [95%CI: 1.8-57.4]; P=0.01); and (ii) presence of an invasive device (OR=7.7 [95%CI: 2.3-25.7]; P=0.001). CONCLUSIONS: Specific interaction between both patient colonization pressure and selective antibiotic pressure is the most relevant factor for P. aeruginosa acquisition on an ICU. This suggests that combined efforts are needed against both factors to decrease colonization with P. aeruginosa

High mean arterial pressure target to improve sepsis-associated acute kidney injury in patients with prior hypertension: a feasibility study

Background : The optimal mean arterial pressure (MAP) in cases of septic shock is still a matter of debate in patients with prior hypertension. An MAP between 75 and 85 mmHg can improve glomerular filtration rate (GFR) but its effect on tubular function is unknown. We assessed the effects of high MAP level on glomerular and tubular renal function in two intensive care units of a teaching hospital. Inclusion criteria were patients with a history of chronic hypertension and developing AKI in the first 24 h of septic shock. Data were collected during two 6 h periods of MAP regimen administered consecutively after haemodynamic stabilisation in an order depending on the patient's admission unit: a high-target period (80–85 mmHg) and a low-target period (65–70 mmHg). The primary endpoint was the creatinine clearance (CrCl) calculated from urine and serum samples at the end of each MAP period by the UV/P formula. Results : 26 patients were included. Higher urine output (+0.2 (95%:0, 0.4) mL/kg/h; P = 0.04), urine sodium (+6 (95% CI 0.2, 13) mmol/L; P = 0.04) and lower serum creatinine (− 10 (95% CI − 17, − 3) µmol/L; P = 0.03) were observed during the high-MAP period as compared to the low-MAP period, resulting in a higher CrCl (+25 (95% CI 11, 39) mL/mn; P = 0.002). The urine creatinine, urine–plasma creatinine ratio, urine osmolality, fractional excretion of sodium and urea showed no significant variation. The KDIGO stage at inclusion only interacted with serum creatinine variation and low level of sodium excretion at inclusion did not interact with these results. Conclusions : In the early stage of sepsis-associated AKI, a high-MAP target in patients with a history of hypertension was associated with a higher CrCl, but did not affect the kidneys' ability to concentrate urine, which may reflect no effect on tubular function

Crit Care Sci

We hypothesized that the use of mechanical insufflation-exsufflation can reduce the incidence of acute respiratory failure within the 48-hour post-extubation period in intensive care unit-acquired weakness patients. This was a prospective randomized controlled open-label trial. Patients diagnosed with intensive care unit-acquired weakness were consecutively enrolled based on a Medical Research Council score ≤ 48/60. The patients randomly received two daily sessions; in the control group, conventional chest physiotherapy was performed, while in the intervention group, chest physiotherapy was associated with mechanical insufflation-exsufflation. The incidence of acute respiratory failure within 48 hours of extubation was evaluated. Similarly, the reintubation rate, intensive care unit length of stay, mortality at 28 days, and survival probability at 90 days were assessed. The study was stopped after futility results in the interim analysis. We included 122 consecutive patients (n = 61 per group). There was no significant difference in the incidence of acute respiratory failure between treatments (11.5% control group versus 16.4%, intervention group; p = 0.60), the need for reintubation (3.6% versus 10.7%; p = 0.27), mean length of stay (3 versus 4 days; p = 0.33), mortality at Day 28 (9.8% versus 15.0%; p = 0.42), or survival probability at Day 90 (21.3% versus 28.3%; p = 0.41). Mechanical insufflation-exsufflation combined with chest physiotherapy seems to have no impact in preventing postextubation acute respiratory failure in intensive care unit-acquired weakness patients. Similarly, mortality and survival probability were similar in both groups. Nevertheless, given the early termination of the trial, further clinical investigation is strongly recommended. NCT01931228

Twenty-three unsolved problems in hydrology (UPH) – a community perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Evaluation d'un protocole de sédation intra veineuse en objectif de concentration au Propofol lors des séances de ventilation non invasive (étude de faisabilité chez des patients de réanimation en échec de ventilation non invasive par intolérance à cette technique)

La ventilation non invasive (VNI) a fait ses preuves dans la prise en charge des patients atteints d'une défaillance respiratoire. sa mauvaise tolérance en est une des limites actuelles. Pour de rares patients, souvent les plus fragiles, cette intolérance impose un recours à l'intubation. La sédation constitue actuellement une contre indication à la VNI. Mais les nouveaux agents hypnotiques et surtout leur administration dite en "objectif de concentration" (AIVOC) permettent d'envisager la remise en question de ce dogme. Nous avons réalisé un total de 23 séances de VNI, en mode VS-AI-PEP sur des "respirateurs lourds" sous AIVOC au Propofol, chez 5 patients à risque d'échec de la VNI, par intolérance à cette technique, soit un total de 2525 minutes de sédation. La durée moyenne des séances est de 109 min (+-55). La concentration -cible moyenne nécessaire pour obtenir le niveau de sédation souhaité est de 0,97 g/ml (+-0,32). Même si certains ont présenté des épisodes d'over-sédation (OS) prolongés, les patients ont dans l'ensemble passés plus de 96% du temps dans le niveau de sédation désiré (évalué à 4 sur l'échelle OAA/S). Ces épisodes d'OS n'ont jamais entraîné de complications graves, en particulier, aucun épisode d'apnée ou désaturation. Pour maintenir les patients dans le niveau de sédation souhaité, 31 modifications thérapeutiques ont été effectuées. Ceci représente une présence médicale de 203min (8% du temps total de sédation). Le confort est jugé "bon" ou "excellent" chez l'ensemble des patients. On ne signale pas de fuites inhabituelles autour de l'interface. Sur le plan gazométrique, la VNI sous SIVOC permet d'améliorer de façon significative le pH (7,37 vs 7,40 ; p<0,008). L'amélioration de la pCO2 (7,33 vs 7,08 Kpa ; p=0,06) est à la limite de signifcativité. Le protocole d'administration et de surveillance proposé permet de garantir des conditions de sécurité stisgaisantes. Les rares complications rencontrées ont été corrigées rapidement et sont restées sans conséquence. Notre travail montre que cfhez 5 patients de réanimation en échec de VNI par intolérance à cette technique, une sédation en mode AIVOC au propofol autorise la poursuite la VNI permettant ainsi d'éviter le recours à l'intubation.BORDEAUX2-BU Santé (330632101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Ventilation par percussion intra pulmonaire et explorasions fonctionnelles respiratoires dans l'insuffisance respiratoire aigüe des patients avec broncho-pneumopathie chronique obstructive

Les patients avec broncho-pneumopathie chronique obstructive (BPCO) sont fréquemment admis en réanimation pour décompensation respiratoire. Le bénéfice de la ventilation non invasive chez ces patients BPCO en acidose respiratoire est clairement démontré. La ventilation par percussion intra pulmonaire, technique de ventilation non invasive, destinée à la mobilisation thérapeutique des sécrétions bronchiques pourrait être un traitement utile contre la distension en drainant les sécrétions et ainsi en diminuant les résistances. Les patients avec broncho-pneumopathie chronique obstructive (BPCO) font partie des malades les plus difficiles à sevrer du respirateur et les échecs d'extubation y sont assez fréquents. Plusieurs études ont confirmé le mauvais pronostic de la reintubation à l'issue du sevrage et montré qu'il serait utile d'individualiser pécocement les patients BPCO "à haut risque" de nouvelle décompensation à l'issue du sevrage. Nous avons montré que la ventilation par percussion intra pulmonaire, prescrite chez des patients BPCO en exacerbation aigue avec acidose respiratoire modérée, évitait la poursuite de l'aggravation de ces patients. Une séance de percussion intra pulmonaire s'accompagnait d'une amélioration de la PaO2 et une diminution de la PaCO2. Nous avons également évalué l'intérêt de mesure précoce, une heure après extubation de la pression d'occlusion P0.1 et de la limitation de débit expiratoire pour définir des patients BPCO à haut risque de détresse respiratoire en post extubation. Enfin, si la limitation du débit expiratoire joue un rôle néfaste en post extubation, à l'inverse toute intervention susceptible de faciliter le débit expiratoire, par exemple en mobilisant les sécrétions bronchiques et en réduisant l'encombrement, sera bénéfique. Nous avons ainsi montré que la ventilation par percussion intra pulmonaire permettait une diminution significative de la limitation de débit expiratoire et de la pression d'occlusion.Acute respiratory failure (ARF) in patients with chronic obstructive pulmonary disease (COPD) is a frequent reason for admission in intensive care unit. It has been demonstrated that non invasive ventilation can reverse acute respiratory failure in a significant portion of patients with exacerbation of COPD. Intrapulmonary percussive ventilation (IPV), intended for the therapeutic mobilization of bronchial secretions could offer a treatment directed against the onset of decompensation, specifically the increase in airway mucus that is responsible for increasing airway resistance. COPD patients present with a high risk of muscular respiratory failure and may prove difficult to wean. Extubation failure is an independent risk factor for nosocomial pneumonia and mortality in mechanically ventilated patients. The frequency unfavourable impact of reintubation on outcome indicates that accurate prediction of extubation outcome would be potentially important. We have demonstrated that IPV is a safe technique and may prevent deterioration in cases of acute exacerbations of COPD with mild respiratory acidosis. IPV led to a significant decrease in respiratory rate, a, increase in PaO2 and a decrease in PaCO2. We have showed that early measurements, one hour after extubation, of airway occlusion pressure (P0.1) and expiratory limitation of flow by the negative expiratory pressure method could individualize COPD patients at high risk of acute respiratory failure in the period following extubation. We have also studied the interest of intrapulmonary percussive ventilation in COPD patients studied in post extubation with a high risk of acute respiratory failure and demonstrated that a session of IPV allowed a significant reduction of expiratory flow limitation and of airway occlusion pressure.BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Methadone-Induced Toxic Brain Damage

A 29-year-old man presented with comatose after methadone intoxication. Cerebral tomography only showed cortico-subcortical hypodense signal in the right cerebellar hemisphere. Brain MRI showed a rare imaging of FLAIR and DWI hyperintensities in the two cerebellar hemispheres as well as basal ganglia (globi pallidi), compatible with methadone overdose. To our knowledge this is the first reported case of both cerebellar and basal ganglia involvement in methadone overdose