Numerical simulation on a horizontal airflow for airborne particles control in hospital operating room

Provision of downward unidirectional clean air has been prevalent for decades in modern hospital operating rooms (ORs) to protect patients and surgeons from infectious airborne particles and has been found to be effective in reducing Surgical Site Infection (SSI), however, its shortcomings are inevitable. In this study we investigated an alternative of horizontal airflow pattern and the airflow performance in an OR with a dimension of 300 cm long, 296 cm wide and 240 cm high. We also evaluated the effectiveness of the horizontal unidirectional airflow to control infectious airborne particles through onsite test and computational fluid dynamics (CFD) simulation method. The investigation was focused mainly on the influence of the medical lamps and the thermal plume with different airflow patterns around the critical zone under the horizontal air supply system. Ultraclean air was supplied from a fan-filter unit. The patient and surgeon were assumed to be releasing 200 and 400 particles per minute, respectively. The results show that when the air supply and return facilities are installed on the same lateral wall to keep a state of horizontal flow ventilation in the OR, medical lamps and the thermal plume have no obvious influence on the horizontal airflow patterns around the critical zone in the OR, and performance of the air supply system is highly related to the relative position of the source to the wound.