The Influence of Surgical Staff Behavior on Air Quality in a Conventionally Ventilated Operating Theatre during a Simulated Arthroplasty: A Case Study at the University Hospital of Parma.

Surgical staff behavior in operating theatres is one of the factors associated with indoor air quality and surgical site infection risk. The aim of this study was to apply an approach including microbiological, particle, and microclimate parameters during two simulated surgical hip arthroplasties to evaluate the influence of staff behavior on indoor air quality. During the first hip arthroplasty, the surgical team behaved correctly, but in the second operation, behavioral recommendations were not respected. Microbiological contamination was evaluated by active and passive methods. The air velocity, humidity, temperature, and CO2 concentration were also monitored. The highest levels of microbial and particle contamination, as well as the highest variation in the microclimate parameter, were recorded during the surgical operation where the surgical team behaved "incorrectly". Turbulent air flow ventilation systems appeared more efficient than in the past and very low air microbial contamination was reached when behavior was correct. Therefore, adherence to behavioral recommendations in operating theatres is essential to not undermine the effectiveness of the heating, ventilation, and air conditioning systems and employed resources.

Hospital ventilation simulation for the study of potential exposure to contaminants.

Airflow and ventilation are particularly important in healthcare rooms for controlling thermo-hygrometric conditions, providing anaesthetic gas removal, diluting airborne bacterial contamination and minimizing bacteria transfer airborne. An actual hospitalization room was the investigate case study. Transient simulations with computational fluid dynamics (CFD), based on the finite element method (FEM) were performed to investigate the efficiency of the existing heating, ventilation and air-conditioning (HVAC) plant with a variable air volume (VAV) primary air system. Solid modelling of the room, taking into account thermo-physical properties of building materials, architectural features (e.g., window and wall orientation) and furnishing (e.g., beds, tables and lamps) arrangement of the room, inlet turbulence high induction air diffuser, the return air diffusers and two patients lying on two parallel beds was carried out. Multiphysics modelling was used: a thermo-fluidynamic model (convection-conduction and incompressible Navier-Stokes) was combined with a convection-diffusion model. Three 3D models were elaborated considering different conditions/events of the patients (i.e., the first was considered coughing and/or the second breathing). A particle tracing and diffusion model, connected to cough events, was developed to simulate the dispersal of bacteria-carrying droplets in the isolation room equipped with the existing ventilation system. An analysis of the region of droplet fallout and the dilution time of bacteria diffusion of coughed gas in the isolation room was performed. The analysis of transient simulation results concerning particle path and distance, and then particle tracing combined with their concentration, provided evidence of the formation of zones that should be checked by microclimatic and contaminant control. The present study highlights the fact that the CFD-FEM application is useful for understanding the efficiency, adequacy and reliability of the ventilation system, but also provides important suggestions for controlling air quality, patients' comfort and energy consumption in a hospital.