Modeling of aerosol transmission of airborne pathogens in ICU rooms of COVID-19 patients with acute respiratory failure

Abstract

The COVID-19 pandemic has generated many concerns about cross-contamination risks, particularly in hospital settings and Intensive Care Units (ICU). Virus-laden aerosols produced by infected patients can propagate throughout ventilated rooms and put medical personnel entering them at risk. Experimental results found with a schlieren optical method have shown that the air flows generated by a cough and normal breathing were modified by the oxygenation technique used, especially when using High Flow Nasal Canulae, increasing the shedding of potentially infectious airborne particles. This study also uses a 3D Computer Fluid Dynamics model based on a Lattice Boltzmann Method to simulate the air flows as well as the movement of numerous airborne particles produced by a patient’s cough within an ICU room under negative pressure. The effects of different mitigation scenarii on the amount of aerosols potentially containing SARS-CoV-2 that are extracted through the ventilation system are investigated. Numerical results indicate that adequate bed orientation and additional air treatment unit positioning can increase by 40% the number of particles extracted and decrease by 25% the amount of particles deposited on surfaces 45s after shedding. This approach could help lay the grounds for a more comprehensive way to tackle contamination risks in hospitals, as the model can be seen as a proof of concept and be adapted to any room configuration.

Numerical Modeling of Face Shield Protection against a Sneeze

“…The numerical model based on CFD techniques proposed in the current study was defined to evaluate face coverings on airborne transmission risks and, therefore, no empirical or statistical model was included for modeling the rate of infection. Crawford et al [38] showed that the assessment of the exposure time and/or the minimum viral load required to become infected is relevant. The risk of infection could be found by using a dose-response equation, along with the total amount of virus present in the air and the exposure time; see the case study evaluating the risk of infection by Adhikari et al [39].…”

Exhaled Jet and Viral-Laden Aerosol Transport from Nasal Sneezing

“…A N U S C R I P T 3 sneeze, and talking produced from the oral cavity (Johnson et al, 2011;Lee et al, 2019;Stadnytskyi et al, 2021;El Hassan et al, 2022), as well as aerosol dispersion inside a room (Inthavong et al, 2013;Heschl et al, 2014;Ji et al, 2018;Tao et al, 2020;Bathula et al, 2021;Crawford et al, 2021;Shah et al, 2021;Shrestha et al, 2021) and outdoor environments (Feng et al, 2020;Gorbunov, 2021). Additionally, studies (Zhu et al, 2006;Scharfman et al, 2016) demonstrated the oral cough produced a droplet-laden cough jet and puff dynamics, as well as review articles on the fluid dynamics of respiratory droplets (Dbouk and Drikakis, 2020;Mittal et al, 2020;Katre et al, 2021), and mitigation strategies for reducing viral transmission (Hui et al, 2012;Khosronejad et al, 2020;Salati et al, 2021).…”

Rôle de la transmission air lors d’un Cluster de cas Covid-19 en Pneumologie : investigation épidémiologique, analyse génomique et modélisation d’aérosols

“…La pandémie COVID-19 a suscité de nombreuses inquiétudes quant aux risques de contamination croisée en milieu hospitalier. Les aérosols chargés de virus produits par les patients infectés peuvent se propager dans les pièces mal ventilées et mettre en danger les soignants et les patients non infectés [1] .…”

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Introduction La pandémie COVID-19 a suscité de nombreuses inquiétudes quant aux risques de contamination croisée en milieu hospitalier. Les aérosols chargés de virus produits par les patients infectés peuvent se propager dans les pièces mal ventilées et mettre en danger les soignants et les patients non infectés [1] .

Objectif Caractérisation du mode de transmission air de SARS Cov-2, lors de deux clusters Covid-19 en janvier et avril 2021 dans un service de Pneumologie.

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