Surgical site infection (SSI) is a major complication following surgery and is associated with increased morbidity and mortality, as well as increased costs. The function of operating room (OR) ventilation is to prevent airborne microbial contaminants from entering surgical wounds. Under normal circumstances, the main source of airborne microbial contamination is microscopic skin fragments, contaminated with bacteria, shed by healthcare workers (HCWs) in the OR. Another potential source of airborne microorganisms are air supplies that are not properly filtered. The need for routine microbiological sampling of ORs is controversial. There is no national or international consensus on the methods, frequency, types of sampling or acceptable levels of microbial contamination in a functioning OR. However, there is evidence to support microbiological air sampling of ORs as part of the commissioning process of a new facility or following major refurbishment, as an adjunct to other heating, ventilation and air conditioning (HVAC) quality assurance controls. The purpose of microbiological air sampling is to gauge the efficacy of the HVAC systems, including high-efficiency particulate air (HEPA) filters following installation or after major structural refurbishment.

The Department of Health WA’s operational directive on this issue can be found at www.health.wa.gov.au/circularsnew.