Surgical site infections (SSIs) can pose several risks for patients and institutions, including increased lengths of stay, higher costs, and higher morbidity rates following surgery. Laminar airflow (LAF) is used in many surgical operating rooms (ORs) to decrease the amount of bacterial colony-forming units (CFUs) that might infect patients undergoing surgery. However, there are many variables that might disrupt the efficacy of LAF, such as the bodily movements of surgical personnel or the opening and closing of nearby doors. Further research is needed to better understand the level to which these variables contribute to SSI rates in ORs.
To measure and assess bacterial contamination levels within an OR environment as a function of laminar airflow, door openings, and other potential variables.
This study took place in a single OR over a six-week period, during which 48 general and orthopedic surgical procedures were performed as normal. Researchers measured the average amounts of CFUs both outside and inside the LAF area by placing bacterial settle plates near exit doors and on instrument tables. Researchers also kept note of all patient health backgrounds, lengths of surgical procedures, times of day, number of staff present, room temperature, and humidity. The number of times doors were opened was counted manually throughout the duration of the study.
Outside of LAF range, door openings and longer surgery durations were associated with higher CFU counts. Inside of LAF range, higher numbers of staff members occupying the OR was associated with higher CFU counts. The number of door openings per surgical procedure was positively correlated with longer surgical durations, indicating that longer surgeries usually require additional door openings and can subsequently lead to higher CFU presence.
The authors note that during the course of the study, one of the instrument tables would be moved out of LAF range so that the OR could accommodate more staff members, which more than likely influenced CFU average during final analysis. The authors also note that the Hawthorne effect could have affected results, since these procedures were not blinded to OR staff. This study was conducted in one facility, and the floor plans of each OR within the facility were not factored into the study design.