Can clothing systems and human activities in operating rooms with mixing ventilation systems help achieve 10 CFU/m3 level during orthopaedic surgeries?

The level of airborne microbial contamination in operating rooms (ORs) is an important indicator of indoor air quality and ensures a clean surgical environment. It is necessary to research how different factors affect the colony forming unit (CFU) level during surgery in a mixing ventilation (MV) operating room (OR) to fulfil an ultra-clean air requirement. The main objective of this study is to clarify the possibility of achieving the requirement for an ultraclean operating room (≤ 10 CFU/m3) with mixing ventilation from two factors of clothing and human activities. The experiment results verified that the average CFU/m3 of three of five mock-up surgeries was 8.5 which was below or equal to the ultra-clean requirement, while the other two mock-up surgeries did not meet the ultra-clean requirement. Surgical activities together with clothing level of surgical staff in ORs seem to be the most significant reason for the high CFU level during surgery. It is possible to achieve the ultraclean air requirement (≤ 10 CFU/m3) during a surgical process with proper clothing and low surgical activities in ORs. This study clarifies the effect of clothing and human activities on the CFU level in the surgical microenvironment in ORs and contributes to developing new code of products for the surgical team.