Mathematical modeling of pathogen trajectory in a patient care environment.
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OBJECTIVE: Minimizing healthcare worker exposure to airborne infectious pathogens is an important infection control practice. This study utilized mathematical modeling to evaluate the trajectories and subsequent concentrations of particles following a simulated release in a patient care room. DESIGN: Observational study. SETTING: Biocontainment unit patient care room at a university-affiliated tertiary care medical center. METHODS: Quantitative mathematical modeling of airflow in a patient care room was achieved using a computational fluid dynamics software package. Models were created on the basis of a release of particles from various locations in the room. Computerized particle trajectories were presented in time-lapse fashion over a blueprint of the room. A series of smoke tests were conducted to visually validate the model. RESULTS: Most particles released from the head of the bed initially rose to the ceiling and then spread across the ceiling and throughout the room. The highest particle concentrations were observed at the head of the bed nearest to the air return vent, and the lowest concentrations were observed at the foot of the bed. CONCLUSIONS: Mathematical modeling provides clinically relevant data on the potential exposure risk in patient care rooms and is applicable in multiple healthcare delivery settings. The information obtained through mathematical modeling could potentially serve as an infection control modality to enhance the protection of healthcare workers.