Accumulation and transport of microbial-size particles in a pressure protected model burn unit: CFD simulations and experimental evidence

<p>Abstract</p> <p>Background</p> <p>Controlling airborne contamination is of major importance in burn units because of the high susceptibility of burned patients to infections and the unique environmental conditions that can accentuate the infection risk. In particular the required elevated temperatures in the patient room can create thermal convection flows which can transport airborne contaminates throughout the unit. In order to estimate this risk and optimize the design of an intensive care room intended to host severely burned patients, we have relied on a computational fluid dynamic methodology (CFD).</p> <p>Methods</p> <p>The study was carried out in 4 steps: i) patient room design, ii) CFD simulations of patient room design to model air flows throughout the patient room, adjacent anterooms and the corridor, iii) construction of a prototype room and subsequent experimental studies to characterize its performance iv) qualitative comparison of the tendencies between CFD prediction and experimental results. The Electricité De France (EDF) open-source software <it>Code_Saturne</it>^®(<url>http://www.code-saturne.org</url>) was used and CFD simulations were conducted with an hexahedral mesh containing about 300 000 computational cells. The computational domain included the treatment room and two anterooms including equipment, staff and patient. Experiments with inert aerosol particles followed by time-resolved particle counting were conducted in the prototype room for comparison with the CFD observations.</p> <p>Results</p> <p>We found that thermal convection can create contaminated zones near the ceiling of the room, which can subsequently lead to contaminate transfer in adjacent rooms. Experimental confirmation of these phenomena agreed well with CFD predictions and showed that particles greater than one micron (i.e. bacterial or fungal spore sizes) can be influenced by these thermally induced flows. When the temperature difference between rooms was 7°C, a significant contamination transfer was observed to enter into the positive pressure room when the access door was opened, while 2°C had little effect. Based on these findings the constructed burn unit was outfitted with supplemental air exhaust ducts over the doors to compensate for the thermal convective flows.</p> <p>Conclusions</p> <p>CFD simulations proved to be a particularly useful tool for the design and optimization of a burn unit treatment room. Our results, which have been confirmed qualitatively by experimental investigation, stressed that airborne transfer of microbial size particles via thermal convection flows are able to bypass the protective overpressure in the patient room, which can represent a potential risk of cross contamination between rooms in protected environments.</p

Décontamination de surface par un procédé plasma froid à pression atmosphérique

Dans le cadre d'une thèse en partenariat avec un industriel, il s'agit de trouver une solution pour décontaminer biologiquement des surfaces. Le procédé utilisé est un plasma généré par décharge à barrière diélectrique dans l'air et à pression atmosphérique. La décontamination est réalisée par la post-décharge spatiale entraînée par un flux à 10 L/min. Deux types d'échantillons biologiques ont été utilisés (C. glutamicum et B. subtilis) en faisant varier les conditions environnementales comme le débit de gaz, l'humidité de l'air, l'humidité de la surface ou encore la température de la surface sur laquelle sont déposés les échantillons microbiologiques. Certaines de ces conditions de fonctionnement ont montré une efficacité très importante en termes de décroissance microbienne (jusqu'à 4 log en 5 min). A partir de ces résultats, nous avons essayé de comprendre les mécanismes qui interviennent dans la destruction des microorganismes. La thèse s'articule autour, d'une part, des réacteurs plasmas utilisés (architecture, caractéristiques électriques), d'autre part de la chimie en phase gazeuse générée par le passage de l'air plus ou moins humide dans la décharge et enfin des résultats biologiques obtenus.The aim of the study is to find a solution for surface decontamination. The project, build with a firm, was based on cold plasma physic using dielectric barrier discharge at atmospheric pressure. Microorganisms to kill are placed in the post-discharge with gas flow above 10 L/min. Two kinds of bacteria were tested (Corynebacterium glutamicum and spores of Bacillus subtilis) and some treatment conditions were changed: gas flow, relative humidity, surface humidity and temperature. Best performances show a high efficacy (4 log decrease in 5 minutes). From these good results we try to understand mechanisms which kill bacteria. The document discuss on three topics: plasma reactors (structure and electrical properties), gas phase chemistry and biological results.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Etude d'une nouvelle formulation pour comprimés très faiblement dosés et/ou renfermant un principe actif très faiblement soluble

ANGERS-BU Médecine-Pharmacie (490072105) / SudocSudocFranceF

Niveaux, Déterminants et Variabilité des nanoparticules dans l'environnement intérieur - Projet NANOP

http://www.afsset.fr/index.php?pageid=2530&parentid=631National audienceNiveaux, Déterminants et Variabilité des nanoparticules dans l'environnement intérieur - Projet NANO

Niveaux, Déterminants et Variabilité des nanoparticules dans l'environnement intérieur - Projet NANOP

http://www.afsset.fr/index.php?pageid=2530&parentid=631National audienceNiveaux, Déterminants et Variabilité des nanoparticules dans l'environnement intérieur - Projet NANO

Immunomodulatory drugs in multiple myeloma: Impact of the SCARMET (Self CARe and MEdication Toxicity) educational intervention on outpatients' knowledge to manage adverse effects.

Long-term multiple myeloma therapy by immunomodulatory drugs (IMiDs) raises the question of management of adverse effects. The aim of this study is to assess the impact of an educational session for patients on the acquisition of knowledge to manage hematologic and thromboembolic adverse effects of IMiDs. In this prospective single-center study, patients attended an educational session with a hospital clinical pharmacist and a nurse. The primary endpoint was the patient's level of knowledge for the management of IMiDs adverse effects, assess with a dedicated questionnaire administered before the session then 1 and 6 months after. Assessment of knowledge was combined with self-assessment of certainty. The secondary endpoints were adherence and IMiD treatment satisfaction. 50 patients were included. Patient knowledge increased at 1 month (p<0.001) despite a loss of knowledge at 6 months (p<0.05). Six months after the educational intervention, the number of patients with skills considered satisfactory by the pharmacist and nurse increased (p<0.01). Most patients showed satisfactory adherence, with medication possession ratio ≥ 80%. The Self CARe and MEdication Toxicity (SCARMET) study highlighted the impact of multidisciplinary follow-up in multiple myeloma patients to improve knowledge of toxicity self-management