Modélisation de la rigidité et de la perméabilité des grands troncs artériels

Introduction: Les pathologies cardio-vasculaires sont une cause dominante de mortalité dans les sociétés occidentales. Les mathématiques et les progrès de l’ingénierie, en sus de l’approfondissement de la physiologie et physiopathologie, sont de plus en plus fréquemment utilisés pour venir à bout de ce fléau. Méthodes: Nous travaillons au développement et à la validation de modèles théoriques décrivant la filtration des macromolécules à travers les différentes couches de la paroi artérielle. À ces fins, nous avons étudié et caractérisé certaines composantes des parois de l'aorte. Aussi, en guise de validation des modèles de filtration, dans des situations contrôlées, nous étudions la distribution de l’albumine exogène marquée du compartiment vasculaire à travers les différentes couches de la paroi d’aortes thoraciques provenant de lapins normaux. Pour ce faire, nous utilisons la microscopie à fluorescence et l'immunocytochimie en microscopie électronique. Enfin, à l'aide de modèles mathématiques, nous étudions les éléments susceptibles d’expliquer le phénomène de rigidité des gros troncs artériels. Résultats: Nous avons étudié et caractérisé une partie de la couche de surface des cellules endothéliales et l'endothélium luminal aortique. La limitante élastique interne a également été bien étudiée, en particulier la taille des pores de cette dernière ainsi que l'orientation des fibres d'élastine qui la compose. Les résultats préliminaires montrent que les fibres d'élastine de la limitante élastique interne sont majoritairement orientées de manière parallèle à la direction du flot. Au contraire, nos premières observations montrent que les fibres d'élastine de la média sont orientées de manière perpendiculaire à la direction du flot luminal. Enfin, le système vasa vasorum de l’adventice de l’aorte thoracique a été étudié. À l'aide de moulage de l'aorte et d'études en microscopie électronique, nos résultats préliminaires montrent que la densité des vasa vasorum de l'aorte thoracique est plus grande dans sa paroi postérieure que dans sa paroi antérieure. Pour terminer, nous avons approfondi le rôle des érythrocytes dans la filtration des protéines à travers les parois artérielles en déterminant un coefficient de partition des protéines de 0,204 +/- 0,017 entre l'intérieur des érythrocytes et le plasma. Conclusions: Les résultats morphologiques obtenus et l’analyse préliminaire des paramètres physiologiques examinés rejoignent certaines observations disponibles de la littérature. Ces résultats permettront vraisemblablement d'améliorer les modélisations mathématiques des phénomènes de filtration à travers les parois des grands troncs artériels et du phénomène de la rigidité artérielle. De plus, nous présentons le développement d’une technique de validation quantitative des modèles de filtration

Effect of age and sex on echocardiographic left ventricular diastolic function parameters in patients with preserved ejection fraction and normal valvular function

Background: We conducted a retrospective study to specify the effect of age and gender on echocardiographic left ventricular diastolic function parameters.Methods: We included echocardiograms done in our institution between 1995 and 2007, for which data on diastolic function were available. In order to target a population as close aspossible to healthy subjects, echocardiograms reporting abnormal contraction, valvulopathy or extreme data were excluded.Results: A total of 14,298 patients (mean age 58.53 years; men 49.1%) were included in the study. Sex did not influence E/A ratio (p = 0.298) but age decreased it significantly (p < 0.001). E/e ratio increased significantly with age (p < 0.001) and was higher in women than in men (p < 0.001). After the age of 40, more than 10% of the patients had an E/e ratio superior than 8.Conclusions: To our knowledge, this is the most imposing study — in terms of number of patients from first to tenth decade of life that were included — addressing the effect of age and gender on diastolic function. Our results stress the need for future prospective trials to establishnormal diastolic function parameters according to age and gender, notably for the E/e ratio for which a significant proportion of our population had a ratio superior of what is actually considered normal

Multidetector cardiac tomography: A useful tool before cardiac resynchronization therapy

Background: Left ventricular lead placement in a suitable coronary vein is a key determi­nant of responsiveness to cardiac resynchronization therapy (CRT). Multidetector cardiac tomography (MDCT) is a non-invasive alternative to depict cardiac venous anatomy although coronary sinus (CS) retrograde venography (RV) is the gold standard. The aim of this study was to evaluate the accuracy of MDCT to determine the presence of CS tributaries before CRT. Methods: A retrospective analysis of 41 consecutive patients eligible to CRT was performed. MDCT was assessed in all patients before CRT and RV was achieved in 39 patients. Both methods evaluated the presence of the inferior interventricular vein (IIV), posterior vein (PV) and lateral main vein (LMV). CS ostium diameter and distance between the CS ostium and right atrium (RA) lateral wall were also measured. Results: The IIV was identified in 100% of MDCT and in 43.6% of RV. In comparison to RV, the MDCT’s sensitivity to identify PV and LMV was 100% for both, kappa coefficient of 0.792 (CI 95% 0.46–0.93) and 0.69 (CI 95% 0.46–0.91), respectively. There was no significant difference between ischemic and non-ischemic patients regarding the presence of PV or LMV. Median CS antero-posterior diameter was 10.3 mm (IQR 7.5–13) and supero-inferior was 14.1 mm (IQR 11.5–17) (p < 0.01). A positive correlation (p < 0.001) between echocardiographic RA area and the distance from CS ostium to the RA lateral wall in the MDCT was observed. Conclusions: MDCT is as accurate as RV to depict CS and its tributaries (IIV, PV, LMV), and it could be useful as a non-invasive technique before CRT

La rédaction de questions à choix multiple et de questions à réponse ouverte et courte pour les examens écrits dans les programmes de formation en santé : une étude docimologique des consignes de rédaction

Contexte/objectif : L’évaluation des apprentissages a une importance indéniable en pédagogie des sciences de la santé. L’élaboration de questions écrites est toutefois un grand défi bien que l’on retrouve dans la littérature scientifique plus de 150 consignes destinées à en guider la rédaction. Malheureusement, il existe peu de données probantes quant à l’impact de l’utilisation des consignes sur la qualité des questions. L’objectif de cette étude est d’identifier les consignes de rédaction de questions écrites qui permettent de différencier les bonnes des moins bonnes questions, et donc qui devraient être respectées lors de la rédaction de celles-ci. Méthodes : Nous avons sélectionné 36 consignes de rédaction parmi plus de 150 répertoriées dans les écrits scientifiques. Nous les avons utilisés pour évaluer 407 questions : 150 questions à choix multiples (QCM) et 141 questions à réponse ouverte courte (QROC) provenant de banques de questions du programme de médecine de notre institution ainsi que 116 questions QCM provenant d’un précédent projet de recherche. Une analyse d’items, basée sur les principes de la théorie classique des tests, a été réalisée afin d’identifier les consignes de rédaction les plus discriminantes. Résultats : Six consignes de rédaction pour les QROC (discrimination moyenne = 0,20) et huit consignes de rédaction pour les QCM (discrimination moyenne = 0,19 ; accord inter-juges moyen = 0,98) ont été identifiées comme discriminantes. Conclusions : Nos résultats suggèrent que certaines consignes de rédaction de questions d’examens peuvent discriminer entre les bonnes et moins bonnes questions, ce qui pourrait aider à l’élaboration d’examens de plus haute qualité

Acute and recurring pericarditis: More colchicine, less corticosteroids

Acute and recurring pericarditis are frequently encountered clinical entities. Given that severe complications such as tamponade and constrictive pericarditis occur rarely, the majority of patients suffering from acute pericarditis will have a benign clinical course. However, pericarditis recurrence, with its painful symptoms, is frequent. In effect, recent studies have demonstrated a beneficial role of colchicine in preventing recurrence, while also suggesting an increase in recurrences with the use of corticosteroids, the traditional first-line agent

Are hospital nurse staffing practices associated with postoperative cardiac events and death? A systematic review.

INTRODUCTION:Postoperative cardiac events are frequent complications of surgery, and their occurrence could be associated with suboptimal nurse staffing practices, but the existing evidence remains scattered. We systematically reviewed studies linking nurse staffing practices to postoperative cardiac events and two related outcomes, all-cause mortality and failure-to-rescue. METHODS:A systematic search of the English/French literature was undertaken in the CINAHL, PsychInfo, and Medline databases. Studies were included if they: a) were published between 1996 and 2018; b) used a quantitative design; c) examined the association between at least one of seven staffing practices of interest (i.e., staffing levels, skill mix, work environment characteristics, levels of education and experience of the registered nurses, and overtime or temporary staff use) and postoperative cardiac events, mortality or failure-to-rescue; and d) were conducted among surgical patients. Data extraction, analysis, and synthesis, along with study methodological quality appraisal, were performed by two authors. High methodological heterogeneity precluded a formal meta-analysis. RESULTS:Among 3,375 retrieved articles, 44 studies were included (39 cross-sectional, 3 longitudinal, 1 case-control, 1 interrupted time series). Existing evidence shows that higher nurse staffing levels, a higher proportion of registered nurses with an education at the baccalaureate degree level, and more supportive work environments are related to lower rates of both 30-day mortality and failure-to-rescue. Other staffing practices were less often studied and showed inconsistent associations with mortality or failure-to-rescue. Similarly, few studies (n = 10) examined the associations between nurse staffing practices and postoperative cardiac events and showed inconsistent results. CONCLUSION:Higher nurse staffing levels, higher registered nurse education (baccalaureate degree level) and more supportive work environments were cross-sectionally associated with lower 30-day mortality and failure-to-rescue rates among surgical patients, but longitudinal studies are required to corroborate these associations. The existing evidence regarding postoperative cardiac events is limited, which warrants further investigation

Impact of methicillin resistant Staphylococcus aureus contact isolation units on medical care.

BACKGROUND: Patient isolation using contact precautions has gained widespread use to halt MRSA transmission, however supportive data is scarce and concerns regarding patient safety and satisfaction have been raised. At our institution, MRSA patients are isolated on a dedicated ward (cohort isolation), rather than in separate rooms. Our objectives were (1) to determine the proportion of bedside medical visits to patients on an isolation ward, (2) to quantify complications in those patients and (3) to determine if those complications are related to isolation and if they can be prevented. METHODS: This retrospective case-control study was performed on the two sites of a tertiary teaching hospital in Sherbrooke, QC, Canada. We matched MRSA patients with an admission diagnosis of heart failure or chronic obstructive pulmonary disease to similar non-isolated controls. The proportion of bedside visits was ascertained through the number of progress notes with subjective elements or with a physical examination. Complications were sought through an extensive file review, and events were analysed according to Baker's CAES causality and preventability scales. RESULTS: Overall, 111 patient pairs were analysed (35 with heart failure and 76 with COPD). Isolated patients received less bedside visits (subjective notes/1,000 patient-days: 849.6 vs. 983.3, p = 0,001). Attending physicians (454.5 vs. 451.4, p = 0,02) and residents (347.0 vs. 416.9, p = 0.01) are responsible for this discrepancy, while medical students appear to visit isolated and non-isolated patients equally (116.5 vs. 114.9, p = 0.90). Isolated patients showed a tendency towards longer stay and more preventable complications, although no difference in the total number of complications was observed. CONCLUSION: Isolated patients have less documented care that suggests less bedside visits from the medical staff, which could hamper the therapeutical relationship. Further studies are needed to explain this finding