The COVID-19 pandemic has generated many concerns about cross-contamination risks, particularly for Infection Prevention & Control (IPC) teams in hospital settings such as Intensive Care Units (ICU). Virus-laden aerosols produced by infected patients can propagate throughout ventilated rooms and put healthcare workers entering them at risk.
The airflows generated by a cough and normal breathing are modified by the oxygenation technique used in ICUs, and can increase the shedding of potentially infectious airborne particles (ie. High Flow Nasal Canulae), as can be shown through experimental optical techniques. The HVAC system also plays a major role in the dispersion of airborne particles produced by an infectious patient. Finally, external airflows such as wind can also have an impact on airborne particle concentration and deposits on surfaces.

Advanced 3D Computational Fluid Dynamics (CFD) can model complex airflows as well as the movement of numerous aerosols in particular indoor environments such as ICU rooms as confirmed by surface sampling and PCR testing. Numerical simulation is a powerful tool to provide important insights and comparisons between different mitigation scenarii (open window, additional air treatment unit, negative pressure…) in order to reduce contamination risks. It also provides compelling visuals which are important for raising awareness and training purposes. This approach helps lay the ground for a more comprehensive way to tackle contamination risks in hospitals, as it can be adapted to other IPC concerns, such as Surgical Site Infections, Aspergillosis…

References:
1. Crawford, C., Vanoli, E., Decorde, B. et al. Modeling of aerosol transmission of airborne pathogens in ICU rooms of COVID-19 patients with acute respiratory failure. Sci Rep 11, 11778 (2021). https://doi.org/10.1038/s41598-021-91265-5
2. Tandjaoui-Lambiotte, Y., Timsit, J.-F., Alloui, C. et al. Viral Dispersion in the ICU: The Wind Effect. Am J Respir Crit Care Med 4, 204 (2021). https://doi.org/10.1164/rccm.202105-1104LE