Comparison of non-invasive to invasive oxygenation ratios for diagnosing acute respiratory distress syndrome following coronary artery bypass graft surgery: a prospective derivation-validation cohort study

Objective: To determine if non-invasive oxygenation indices, namely peripheral capillary oxygen saturation (SpO2)/ fraction of inspired oxygen (Fi O2) and partial pressure of alveolar oxygen (PAO2)/Fi O2 may be used as effective surrogates for the partial pressure of arterial oxygen (PaO2)/Fi O2. Also, to determine the SpO2/Fi O2 and PAO2/Fi O2 values that correspond to PaO2/Fi O2 thresholds for identifying acute respiratory distress syndrome (ARDS) in patients following coronary artery bypass graft (CABG) surgery. Methods: A prospective derivation-validation cohort study in the Open-Heart ICU of an academic teaching hospital. Recorded variables included patient demographics, ventilator settings, chest radiograph results, and SPO2, PaO2, PAO2, SaO2, and Fi O2. Linear regression modeling was used to quantify the relationship between indices. Receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of the threshold values. Results: One-hundred seventy-five patients were enrolled in the derivation cohort, and 358 in the validation cohort. The SPO2/Fi O2 and PAO2/Fi O2 ratios could be predicted well from PaO2/Fi O2, described by the linear regression models SPO2/Fi O2 = 71.149 + 0.8PF and PAO2/Fi O2 = 38.098 + 2.312PF, respectively. According to the linear regression equation, a PaO2/Fi O2 ratio of 300 equaled an SPO2/Fi O2 ratio of 311 (R2 0.857, F 1035.742, < 0.0001) and a PAO2/Fi O2 ratio of 732 (R2 0.576, F 234.887, < 0.0001). The SPO2/Fi O2 threshold of 311 had 90% sensitivity, 80% specificity, LR+ 4.50, LR- 0.13, PPV 98, and NPV 42.1 for the diagnosis of mild ARDS. The PAO2/Fi O2 threshold of 732 had 86% sensitivity, 90% specificity, LR+ 8.45, LR- 0.16, PPV 98.9, and NPV 36 for the diagnosis of mild ARDS. SPO2/ Fi O2 had excellent discrimination ability for mild ARDS (AUC ± SE = 0.92 ± 0.017; 95% CI 0.889 to 0.947) as did PAO2/ Fi O2 (AUC ± SE = 0.915 ± 0.018; 95% CI 0.881 to0.942). Conclusions: PaO2 and SaO2 correlated in the diagnosis of ARDS, with a PaO2/Fi O2 of 300 correlating to an SPO2/ Fi O2 of 311 (Sensitivity 90%, Specificity 80%). The SPO2/ Fi O2 ratio may allow for early real-time rapid identification of ARDS, while decreasing the cost, phlebotomy, blood loss, pain, skin breaks, and vascular punctures associated with serial arterial blood gas measurements

Large-scale unit commitment under uncertainty: an updated literature survey

The Unit Commitment problem in energy management aims at finding the optimal production schedule of a set of generation units, while meeting various system-wide constraints. It has always been a large-scale, non-convex, difficult problem, especially in view of the fact that, due to operational requirements, it has to be solved in an unreasonably small time for its size. Recently, growing renewable energy shares have strongly increased the level of uncertainty in the system, making the (ideal) Unit Commitment model a large-scale, non-convex and uncertain (stochastic, robust, chance-constrained) program. We provide a survey of the literature on methods for the Uncertain Unit Commitment problem, in all its variants. We start with a review of the main contributions on solution methods for the deterministic versions of the problem, focussing on those based on mathematical programming techniques that are more relevant for the uncertain versions of the problem. We then present and categorize the approaches to the latter, while providing entry points to the relevant literature on optimization under uncertainty. This is an updated version of the paper "Large-scale Unit Commitment under uncertainty: a literature survey" that appeared in 4OR 13(2), 115--171 (2015); this version has over 170 more citations, most of which appeared in the last three years, proving how fast the literature on uncertain Unit Commitment evolves, and therefore the interest in this subject

Le rôle du plissement disharmonique dans la tectogenèse de l'allochtone ardennais

peer reviewe

Thérapies non médicamenteuses dans la maladie d'Alzheimer : comparaison d'ateliers musicaux et non musicaux.

International audienceLes th\é\rapies non m\é\dicamenteuses des d\é\mences, en particulier les interventions musicales, se sont consid\é\rablement d\é\velopp\é\es ces derni\è\res ann\é\es. Si diff\é\rents travaux sugg\è\rent un impact positif de ce type d'intervention sur le comportement, l'humeur ou le fonctionnement cognitif des patients, les \é\tudes m\é\thodologiquement rigoureuses sont rares. Peu d'\é\tudes ont compar\é\ l'effet de l'intervention musicale \à\ une autre activit\é\ plaisante, de telle sorte que la sp\é\cificit\é\ de l'impact de la musique reste \à\ pr\é\ciser. Afin de r\é\pondre \à\ cette question, deux \é\tudes contr\ô\l\é\es randomis\é\es ont \é\t\é\ conduites aupr\è\s de 33 patients souffrant d'une d\é\mence de type Alzheimer \à\ un stade mod\é\r\é\ment s\é\v\è\re \à\ s\é\v\è\re, comparant l'impact d'ateliers musicaux \à\ celui d'ateliers non musicaux (\é\tude 1 : peinture \backslash; \é\tude 2 : cuisine) sur l'\é\tat \é\motionnel des patients. Tous les ateliers propos\é\s am\é\lioraient, \à\ court terme, l'\é\tat \é\motionnel des patients. Toutefois, ce b\é\n\é\fice \é\tait plus important et durable suite \à\ l'intervention musicale s'observant chez la plupart des patients. Contrairement aux autres activit\é\s, l'am\é\lioration de l'\é\tat \é\motionnel persistait apr\è\s l'arr\ê\t de l'intervention musicale. Ces r\é\sultats sugg\è\rent un b\é\n\é\fice sp\é\cifique de la musique sur l'\é\tat \é\motionnel des patients, offrant des perspectives de prise en charge tr\è\s prometteuses

Degradation behavior of 600 V-200 A IGBT modules under power cycling and high temperature environment conditions

International audienceOne challenge for automotive hybrid traction application is the use of high power IGBT modules that can withstand high ambient temperatures, from 90 °C to 120 °C, for reliability purpose. The paper presents ageing tests of 600 V-200 A IGBT modules subjected to power cycling with 60 °C junction temperature swings at 90 °C ambient temperature. Failure modes are described and obtained results on the module characteristics are detailed. Especially, physical degradations are described not only at the package level, like solder attach delaminations, but also at the chip level, with a shift on electrical characteristics such as threshold voltage. Finally, numerical investigations are performed in order to assess the thermal and thermo-mechanical constraints on silicon dies during power cycling and also to estimate the effect of ambient temperature on the mechanical stresses

Modes de vieillissement et de défaillance de modules IGBT sous cyclage actif à haute température

International audienc

The effect of new emergency program on patient length of stay in a teaching hospital emergency department of Tehran

Background and Aim: Ideally, the period of patients admitting in the Emergency Department (ED) should not exceed 6 hours. Prolonged of the patients admitting time affects the ED overcrowding, quality of patient care and patient satisfaction. To evaluate the efficacy of new programs and suggest new strategies to reduce the overcrowding in a typical overcrowded ED of general teaching hospital in Tehran city. Materials and Methods: In this descriptive case study, charts of patients held over 24 hours, in Imam Hossein Hospital affiliated to the Shaheed Beheshti Medical University, were reviewed from April 21 rd on August 23 rd , 2008. Results: Of 15,477 patients, 151 (1%) have been held in the ED over 24 hours. Reasons for this long-stay included:lack of available bed in Intensive Care Unit (ICU) (125 patients), lack of available bed in related wards (18 patients), poor final decision - making by physician (eight patient) Conclusion: Long-term stay of patients in ED of teaching hospital is a major problem. The most frequent cause is a limitation of inpatient beds. The long stay time had not been affected by paraclinic procedures, multispecialities involvement or the lack of obvious diagnosis. The following solution is proposed: (1) creation of a holding unit, (2) active inter-facility transfer and (3) governing admittance of patients who need ICU care to related wards