Background and objective:
Adequate operating room ventilation and air filtration are essential measures to prevent surgical site infections and reduce hospital stays and healthcare expenditures. In addition, the number of operators present and adherence to procedures regarding door opening also have a bearing on the level of air contamination in the room. The aim of our study is to assess how much the number of operators and the opening of doors during surgery affects airborne microbiological contamination.

Methods:
The data were extrapolated from reports of operational controls conducted in the operating rooms of the Santa Maria Alle Scotte Polyclinic from 2018 to 2021. The number of colonies incubated at 22°C and 36°C, collected with SAS (Surface Air System) samplers, was related by Pearsons linear correlation to the number of operators in the rooms and the number of air changes. T-test was used to assess the difference between the mean of colonies detected with doors closed and with doors open.

Results:
The number of colonies incubated at 22°C was correlated only with air changes (R=-0.33; P=0.001). In contrast, those incubated at 36°C were correlated with air changes (R=-0.40; P0.05). In contrast, the difference was statistically significant for those incubated at 36° (P=0.040).

Conclusion:
The number of operators and the air changes have emerged to be important factors for the contamination of the hospital theatres. Further analysis, including other variables such as the type of ventilation (laminar or turbulent) and pressure gradients (between indoor and outdoor environments), are in progress to better describe the level of contaminations.