INFLUENCE OF STAFF BEHAVIOUR ON AIR QUALITY IN A CONVENTIONALLY-VENTILATED OPERATING THEATRE DURING A SIMULATED ARTHROPLASTY: A CASE STUDY AT THE UNIVERSITY HOSPITAL IN PARMA.

Surgical staff behaviour in the operating theatre (OT) is one of the factors associated with the indoor air quality and the risk of surgical site infections (Birgand et al, 2015). The aim of this research was to assess the influence of staff behaviour on air quality in a conventionally-ventilated OT during two simulated hip arthroplasties performed under different surgical team behaviour use conditions. The study was performed in an operating theatre (OT) supplied with turbulent Heating Ventilation Air Conditioning (HVAC) system at the Orthopaedic Department of the University Hospital in Parma. The HVAC system was equipped with high-efficiency particulate air filters, with an efficiency of 99.97% for particles ≥0.3 µm and 15 air changes per hour. The first hip arthroplasty, was performed under "Correct use" (C) and corresponded to the operation performed with the surgical team behaving correctly, regarding in particular the number of people present in the OT, the door openings, the movements inside the OT and the surgical team talking. Simulation was developed considering real events such as surgical staff movements including general movement and three door openings during the surgical operation. The second hip arthroplasty was performed under "Not correct use" (NC), corresponded to the operation with the surgical team behaving not correctly. Fundamental disturbance factors were simulated such as sliding door opening/closing of the OT (25 times), ingoing and outgoing of circulating nurse and anesthetist and the talking and the walking around. Moreover, experimental measurements were carried out also in “at rest” (R) condition before the simulated operations (Figure 1). Bacterial and fungal contamination was evaluated by active (colony forming units per cubic metre, cfu/m³) and passive (Index of Microbial Air contamination, IMA) samplings (Pasquarella et al 2008, ISO 14698-1:2003, Pasquarella et al 2000) at three different points: operating table, intake grill and entrance door. Airborne particles with diameter of ≥0.5 μm were counted on the operating table by a laser particle counter according to ISO 14644-1:2015. Temperature, relative humidity and air velocity were measured respectively at the instrument table, at the intake grill and at the entrance door; mean radiant temperature and CO2 were measured at the operating table. The data acquisition was made in transient condition over a time of second.