Observational study on hospital building heritage and microbiological air quality in the orthopedic operating theater: the IM.PA.C.T. Project.

Background: The study investigated 35 orthopedic OTs [17 with mixed flow (M-OTs), 18 with turbulent flow (T-OTs)].

Methods: The OTs were divided into two categories based on recurring architectural and construction solutions, collected by a survey form: type-A (recently built or renovated rooms), and type-B (other OTs). Assessment of microbial air contamination (colony forming units (cfu)/m3 obtained by active sampling via Surface Air System) was then performed.

Results: In 97% of the OTs, a Total Viable Count (TVC) was within the limits recommended by ISPESL 2009; all A-type OTs, and 94% of B-type passed. The TVC of type-A OTs [median 15 cfu/m3, range 3-158] was lower than that of type-B OTs [median 28 cfu/m3, range 6-206], although the difference was not significant. The number of people in type-A [mean 8.6, range 6-11] was lower than in type-B [mean 9.6, range 7-13] OTs, and when adjusted to the volume of the OT (person/m3), showed a significant correlation with TVC (ρ = 0.383, p <0.05).

Conclusions: In conclusion, the structural factors examined do not appear to significantly affect the microbiological air quality at the specific sampling point. However, further investigations are required to identify the factors that have the greatest effect on TVC.