Local Exhaust Efficiency in an Operating Room Ventilated by Horizontal Unidirectional Airflow

The paper examines the efficiency of a local exhaust applied during an orthopaedic surgical operation. During operations performing hip replacements bone cement is sometimes applied to fasten the new metal hip to the existing thighbone, especially in case of elderly patients. The bone cement emits harmful VOCs that may influence the operating room personnel and the patient. A local exhaust is applied to reduce the VOC concentration in the operating room air, however, apparently without success. The aim is to assess the efficiency of the existing solution and to provide an alternative and better solution. The usual design procedure of local exhaust openings is inadequate in this case due to the fact that both contaminant emission and local exhaust take place under a horizontal unidirectional airflow device. Instead a CFD model is applied to examine the case and to provide the requested ventilation efficiency. The CFD model comprises persons, equipment and ventilation system apart from the local exhaust. The existing solution is found to be highly inadequate and a new solution is provided that considers the substantial influence of the unidirectional airflow.