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

BMC Infectious Diseases

Research Article

Nicolas Laudinet¹  Juliette Larbre¹  Vance Bergeron²  Maurice Mimoun³  Marc Chaouat³  Marc Benbunan⁴  Jean-Patrick Lajonchère⁵  Christian Beauchêne⁶  Jean-Luc Rousset⁶  Sofiane Benhamadouche⁶  Firas Choukri⁷  Francis Derouin⁷ 

[1] Airinspace SAS, Montigny, France;Airinspace SAS, Montigny, France;CNRS UMR, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69007, Lyon, France;Burn Centre, Department of Reconstructive/Plastic Surgery, Rothschild Hospital, Paris, France;Cell Therapy Unit, Saint-Louis hospital, Assistance Publique-Hôpitaux de Paris, France;Direction, Hôpital Saint-Louis, Assistance Publique-Hôpitaux de Paris, France;Electricité De France Research and Development, 6 quai Watier, 78400, Chatou, France;Laboratory of Parasitology-Mycology, Saint-Louis hospital, Assistance Publique-Hôpitaux de Paris, and University Paris, Diderot, France;

关键词: Thermal Convection;    Treatment Room;    Patient Room;    Airborne Contaminate;    Computational Fluid Dynamic Prediction;   

DOI  :  10.1186/1471-2334-11-58

 received in 2010-06-17, accepted in 2011-03-03,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundControlling 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).MethodsThe 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 Code_Saturne® (http://www.code-saturne.org) 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.ResultsWe 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.ConclusionsCFD 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.

【 授权许可】

Unknown   
© Beauchêne et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.