Influence of movements on contaminant transport in an operating room.

The influence of persons' movements on contaminant transport during an orthopedic surgical operation is examined. Orthopedic surgical operations require an ultra clean environment usually provided by a LAF device (laminar airflow). During hip replacements bone cement is sometimes applied. Due to practical reasons cement mixing is performed outside the LAF area. During the cement transport from the mixing location to the surgeon there is a potential risk of bacterial transport to the clean zone. This phenomenon is examined by smoke visualization and computational fluid dynamics (CFD). The movements are modeled by CFD using distributed momentum sources as well as a turbulent kinetic energy source. A significant risk of contaminant transport from the less clean zone to the ultra clean zone is found. The results indicate that it is possible to simulate the influence of movements using a relatively simple CFD model that considers the significant influence of a transient phenomenon in an approximate way. In real-life ventilated enclosures like operating rooms movements take place. Persons' movements may influence the local flow field as well as the contaminant field substantially. Most often movements are ignored in simulations due to the complexity of the phenomenon. This paper presents an indirect and simple method to consider the influence of movements that may enable modelers to include this important phenomenon in the engineering application of CFD. This may improve practical risk assessment--for instance risk assessment of unintended transport of bacteria during orthopedic surgical operations that may jeopardize the hygiene.