Three main strategies exist to prevent surgical site infections following surgery: 1) the patient, 2) the surgical technique, 3) the surgical environment. This study focuses on optimizing the effect of the surgical environment in preventing SSIs (surgical site infections). The authors attempt to understand that the protective potential of operating room (OR) ventilation under different conditions is crucial to optimizing the surgical environment.
The authors focused on how the surgical environment could be optimized to reduce the frequency of SSIs in the study setting. This study investigated the air quality during orthopedic trauma surgery in a displacement-ventilated OR; explored how traffic flow and the number of persons present in the OR affects the air contamination rate in the vicinity of surgical wounds; and identified reasons for door openings in the OR.
The setting was a Swedish university hospital with a high volume of surgical procedures (about 9,000 annually). The study data was collected in three parallel ORs of equal size, each equipped with an upward air-displacement system supplying cool air (2-3 degrees Celsius below room temperature) above the floor in each corner of the room. Data collection consisting of active air sampling and observations was performed during 30 orthopedic procedures. Sampling and data collection were done using a pretested, structured observation form, during the daytime and in most of the cases once a week, over a seven-month period from April to November 2010.
Air sampling was performed during 30 orthopedic operations in a total of 120 air-sampling intervals. In 52 of the 91 air samples collected (57%), the CFU/m3 values exceeded the recommended level of <10 CFU/m3. In addition, the data showed a strongly positive correlation between the total CFU/m3 per operation and total traffic flow per operation after controlling for duration of surgery. A weaker, yet still positive correlation was also found between CFU/m3 and the number of persons present in the OR. Traffic flow, number of persons present, and duration of surgery explained 68% of the variance in total CFU/m3.
Some of the limitations of this study were:
- The data was collected by observation method, which has the potential to introduce observer bias. Observer accuracy in noting the observations is also crucial.
- The potential of bias can be introduced on the observed, thus altering their behavior, which might skew the study findings. The effects of the observer on the observed have not been accounted for, in this study.