Computer-assisted Teaching in Class Situation: a High-school Math Lab on Vectors

published as a volume in Lecture Notes in Computer ScienceInternational audienceThis paper presents our design and experiment of a computerassisted class laboratory on vectors in high-school. Our main goal is to improve the acquisition on notions by all pupils, from advanced level to remedial level. Our secondary goal is to improve the motivation of pupils toward maths and sciences. Our approach consists in making the pupils practice the notions included in a given set of pedagogic objectives, and to do it through real worldinspired problems. We draw on MobiNet, a platform that simulate programmable mobiles on screen and through the network. Our class laboratory consists of a set of pre-programmed interactive simulations, allowing the pupils to react on their errors and to validate each exercise in an autonomous way. This class laboratory was conducted in the same conditions and constraints than an ordinary math lab: same duration, and no preparation of the pupils (but the ordinary math course). Still, the autonomy of the exercises and the network ability would also allow the use with no teacher on place. In this paper, we describe our vector class laboratory experiment: objectives, design, conduction, and evaluation

Association of intensity of ventilation with 28-day mortality in COVID-19 patients with acute respiratory failure: insights from the PRoVENT-COVID study

Background: The intensity of ventilation, reflected by driving pressure (ΔP) and mechanical power (MP), has an association with outcome in invasively ventilated patients with or without acute respiratory distress syndrome (ARDS). It is uncertain if a similar association exists in coronavirus disease 2019 (COVID-19) patients with acute respiratory failure. Methods: We aimed to investigate the impact of intensity of ventilation on patient outcome. The PRoVENT-COVID study is a national multicenter observational study in COVID-19 patients receiving invasive ventilation. Ventilator parameters were collected a fixed time points on the first calendar day of invasive ventilation. Mean dynamic ΔP and MP were calculated for individual patients at time points without evidence of spontaneous breathing. A Cox proportional hazard model, and a double stratification analysis adjusted for confounders were used to estimate the independent associations of ΔP and MP with outcome. The primary endpoint was 28-day mortality. Results: In 825 patients included in this analysis, 28-day mortality was 27.5%. ΔP was not independently associated with mortality (HR 1.02 [95% confidence interval 0.88–1.18]; P = 0.750). MP, however, was independently associated with 28-day mortality (HR 1.17 [95% CI 1.01–1.36]; P = 0.031), and increasing quartiles of MP, stratified on comparable levels of ΔP, had higher risks of 28-day mortality (HR 1.15 [95% CI 1.01–1.30]; P = 0.028). Conclusions: In this cohort of critically ill invasively ventilated COVID-19 patients with acute respiratory failure, we show an independent association of MP, but not ΔP with 28-day mortality. MP could serve as one prognostic biomarker in addition to ΔP in these patients. Efforts aiming at limiting both ΔP and MP could translate in a better outcome. Trial registration Clinicaltrials.gov (study identifier NCT04346342). [Figure not available: see fulltext.

Mortality associated with early changes in ARDS severity in COVID-19 patients - Insights from the PRoVENT-COVID study

PURPOSE: We investigated changes in ARDS severity and associations with outcome in COVID-19 ARDS patients. METHODS: We compared outcomes in patients with ARDS classified as 'mild', 'moderate' or 'severe' at calendar day 1, and after reclassification at calendar day 2. The primary endpoint was 28-day mortality. We also identified which ventilatory parameters had an association with presence of severe ARDS at day 2. We repeated the analysis for reclassification at calendar day 4. RESULTS: Of 895 patients, 8.5%, 60.1% and 31.4% had mild, moderate and severe ARDS at day 1. These proportions were 13.5%, 72.6% and 13.9% at day 2. 28-day mortality was 25.3%, 31.3% and 32.0% in patients with mild, moderate and severe ARDS at day 1 (p = 0.537), compared to 28.6%, 29.2% and 44.3% in patients reclassified at day 2 (p = 0.005). No ventilatory parameter had an independent association with presence of severe ARDS at day 2. Findings were not different reclassifying at day 4. CONCLUSIONS: In this cohort of COVID-19 patients, ARDS severity and mortality between severity classes changed substantially over the first 4 days of ventilation. These findings are important, as reclassification could help identify target patients that may benefit from alternative approaches

Prognostication using SpO2/FiO2 in invasively ventilated ICU patients with ARDS due to COVID-19 - Insights from the PRoVENT-COVID study

BACKGROUND: The SpO2/FiO2 is a useful oxygenation parameter with prognostic capacity in patients with ARDS. We investigated the prognostic capacity of SpO2/FiO2 for mortality in patients with ARDS due to COVID-19. METHODS: This was a post-hoc analysis of a national multicenter cohort study in invasively ventilated patients with ARDS due to COVID-19. The primary endpoint was 28-day mortality. RESULTS: In 869 invasively ventilated patients, 28-day mortality was 30.1%. The SpO2/FiO2 on day 1 had no prognostic value. The SpO2/FiO2 on day 2 and day 3 had prognostic capacity for death, with the best cut-offs being 179 and 199, respectively. Both SpO2/FiO2 on day 2 (OR, 0.66 [95%-CI 0.46-0.96]) and on day 3 (OR, 0.70 [95%-CI 0.51-0.96]) were associated with 28-day mortality in a model corrected for age, pH, lactate levels and kidney dysfunction (AUROC 0.78 [0.76-0.79]). The measured PaO2/FiO2 and the PaO2/FiO2 calculated from SpO2/FiO2 were strongly correlated (Spearman's r = 0.79). CONCLUSIONS: In this cohort of patients with ARDS due to COVID-19, the SpO2/FiO2 on day 2 and day 3 are independently associated with and have prognostic capacity for 28-day mortality. The SpO2/FiO2 is a useful metric for risk stratification in invasively ventilated COVID-19 patients

Epidemiology, Ventilation Management and Outcomes of COPD Patients Receiving Invasive Ventilation for COVID-19-Insights from PRoVENT-COVID

Chronic obstructive pulmonary disease (COPD) is a risk factor for death in patients admitted to intensive care units (ICUs) for respiratory support. Previous reports suggested higher mortality in COPD patients with COVID-19. It is yet unknown whether patients with COPD were treated differently compared to non-COPD patients. We compared the ventilation management and outcomes of invasive ventilation for COVID-19 in COPD patients versus non-COPD patients. This was a post hoc analysis of a nation-wide, observational study in the Netherlands. COPD patients were compared to non-COPD patients with respect to key ventilation parameters. The secondary endpoints included adjunctive treatments for refractory hypoxemia, and 28-day mortality. Of a total of 1090 patients, 88 (8.1%) were classified as having COPD. The ventilation parameters were not different between COPD patients and non-COPD patients, except for FiO2, which was higher in COPD patients. Prone positioning was applied more often in COPD patients. COPD patients had higher 28-day mortality than non-COPD patients. COPD had an independent association with 28-day mortality. In this cohort of patients who received invasive ventilation for COVID-19, only FiO2 settings and the use of prone positioning were different between COPD patients and non-COPD patients. COPD patients had higher mortality than non-COPD patients

Optimal Dosing and Timing of High-Dose Corticosteroid Therapy in Hospitalized Patients With COVID-19: Study Protocol for a Retrospective Observational Multicenter Study (SELECT)

Background: In hospitalized patients with COVID-19, the dosing and timing of corticosteroids vary widely. Low-dose dexamethasone therapy reduces mortality in patients requiring respiratory support, but it remains unclear how to treat patients when this therapy fails. In critically ill patients, high-dose corticosteroids are often administered as salvage late in the disease course, whereas earlier administration may be more beneficial in preventing disease progression. Previous research has revealed that increased levels of various biomarkers are associated with mortality, and whole blood transcriptome sequencing has the ability to identify host factors predisposing to critical illness in patients with COVID-19. Objective: Our goal is to determine the most optimal dosing and timing of corticosteroid therapy and to provide a basis for personalized corticosteroid treatment regimens to reduce morbidity and mortality in hospitalized patients with COVID-19. Methods: This is a retrospective, observational, multicenter study that includes adult patients who were hospitalized due to COVID-19 in the Netherlands. We will use the differences in therapeutic strategies between hospitals (per protocol high-dose corticosteroids or not) over time to determine whether high-dose corticosteroids have an effect on the following outcome measures: mechanical ventilation or high-flow nasal cannula therapy, in-hospital mortality, and 28-day survival. We will also explore biomarker profiles in serum and bronchoalveolar lavage fluid and use whole blood transcriptome analysis to determine factors that influence the relationship between high-dose corticosteroids and outcome. Existing databases that contain routinely collected electronic data during ward and intensive care admissions, as well as existing biobanks, will be used. We will apply longitudinal modeling appropriate for each data structure to answer the research questions at hand. Results: As of April 2023, data have been collected for a total of 1500 patients, with data collection anticipated to be completed by December 2023. We expect the first results to be available in early 2024. Conclusions: This study protocol presents a strategy to investigate the effect of high-dose corticosteroids throughout the entire clinical course of hospitalized patients with COVID-19, from hospital admission to the ward or intensive care unit until hospital discharge. Moreover, our exploration of biomarker and gene expression profiles for targeted corticosteroid therapy represents a first step towards personalized COVID-19 corticosteroid treatment

Optimal texture image segmentation using multiple matched transforms

This paper deals with a new method for texture analysis based on the Karhunen Loeve Transform (KLT). KLT allows an optimal and compact description of textures. During a training step, filter sets matched to each analyzed texture are computed . Automatic image segmentation is performed classifying each pixel according ta its texture attribute vector. A pixel belongs to the class corresponding to the filter set which tends ta an optimal share out of its "texture energy ". The decision rule is based on the Maximum Likelihood principle . The critical problem of choising the most relevant texture attributes is automaticaly solved by the proposed method. Thus, different texture classes can be processed.Dans cet article nous présentons une méthode statistique d'analyse de textures fondée sur la Transformée de Karhunen-Loeve (T.K.L.). La TKL permet une description compacte et optimale de la texture. Des bancs de filtres adaptés à chaque texture de l'image (filtres RIF) sont déterminés durant une phase d'apprentissage. La segmentation automatique d'une image de texture est réalisée par classement automatique des pixels sur la base des valeurs prises par leur vecteur d'attributs de texture. Le banc de filtres qui assure une répartition optimale de «l'énergie de texture» dans le voisinage du pixel considéré détermine sa classe d'affectatio

Associations of Body Mass Index with Ventilation Management and Clinical Outcomes in Invasively Ventilated Patients with ARDS Related to COVID-19-Insights from the PRoVENT-COVID Study

We describe the practice of ventilation and mortality rates in invasively ventilated normal-weight (18.5 ≤ BMI ≤ 24.9 kg/m2), overweight (25.0 ≤ BMI ≤ 29.9 kg/m2), and obese (BMI > 30 kg/m2) COVID-19 ARDS patients in a national, multicenter observational study, performed at 22 intensive care units in the Netherlands. The primary outcome was a combination of ventilation variables and parameters over the first four calendar days of ventilation, including tidal volume, positive end-expiratory pressure (PEEP), respiratory system compliance, and driving pressure in normal-weight, overweight, and obese patients. Secondary outcomes included the use of adjunctive treatments for refractory hypoxaemia and mortality rates. Between 1 March 2020 and 1 June 2020, 1122 patients were included in the study: 244 (21.3%) normal-weight patients, 531 (47.3%) overweight patients, and 324 (28.8%) obese patients. Most patients received a tidal volume < 8 mL/kg PBW; only on the first day was the tidal volume higher in obese patients. PEEP and driving pressure were higher, and compliance of the respiratory system was lower in obese patients on all four days. Adjunctive therapies for refractory hypoxemia were used equally in the three BMI groups. Adjusted mortality rates were not different between BMI categories. The findings of this study suggest that lung-protective ventilation with a lower tidal volume and prone positioning is similarly feasible in normal-weight, overweight, and obese patients with ARDS related to COVID-19. A patient's BMI should not be used in decisions to forgo or proceed with invasive ventilation

Incidence of Air Leaks in Critically Ill Patients with Acute Hypoxemic Respiratory Failure Due to COVID-19

Subcutaneous emphysema, pneumothorax and pneumomediastinum are well-known complications of invasive ventilation in patients with acute hypoxemic respiratory failure. We determined the incidences of air leaks that were visible on available chest images in a cohort of critically ill patients with acute hypoxemic respiratory failure due to coronavirus disease of 2019 (COVID-19) in a single-center cohort in the Netherlands. A total of 712 chest images from 154 patients were re-evaluated by a multidisciplinary team of independent assessors; there was a median of three (2-5) chest radiographs and a median of one (1-2) chest CT scans per patient. The incidences of subcutaneous emphysema, pneumothoraxes and pneumomediastinum present in 13 patients (8.4%) were 4.5%, 4.5%, and 3.9%. The median first day of the presence of an air leak was 18 (2-21) days after arrival in the ICU and 18 (9-22)days after the start of invasive ventilation. We conclude that the incidence of air leaks was high in this cohort of COVID-19 patients, but it was fairly comparable with what was previously reported in patients with acute hypoxemic respiratory failure in the pre-COVID-19 era

2,6-Bis[(S)-4-benzyl-4,5-dihydro-1,3-oxazol-2-yl]pyridine

The commercially available title compound, C25H23N3O2, has been known since 1993 [Nesper et al. (1993 ▶). Helv. Chim. Acta, 76, 2239–2249], but has not been structurally characterized until now. In the free ligand, the N atoms of both oxazoline rings point in opposite directions. The phenyl rings make dihedral angles of 30.56 (5) and 84.57 (3)° with the pyridine ring and 72.85 (3)° with each other