Traffic flow and microbial air contamination in operating rooms at a major teaching hospital in Ghana.

Background
Current literature examining the relationship between door-opening rate, number of people present, and microbial air contamination in the operating room is limited. Studies are especially needed from low- and middle-income countries, where the risk of surgical site infections is high.

Aim
To assess microbial air contamination in operating rooms at a Ghanaian teaching hospital and the association with door-openings and number of people present. Moreover, we aimed to document reasons for door-opening.

Methods
We conducted active air-sampling using an MAS 100® portable impactor during 124 clean or clean-contaminated elective surgical procedures. The number of people present, door-opening rate and the reasons for each door-opening were recorded by direct observation using pretested structured observation forms.

Findings
During surgery, the mean number of colony-forming units (cfu) was 328 cfu/m3 air, and 429 (84%) of 510 samples exceeded a recommended level of 180 cfu/m3. Of 6717 door-openings recorded, 77% were considered unnecessary. Levels of cfu/m3 were strongly correlated with the number of people present (P = 0.001) and with the number of door-openings/h (P = 0.02). In empty operating rooms, the mean cfu count was 39 cfu/m3 after 1 h of uninterrupted ventilation and 52 (51%) of 102 samples exceeded a recommended level of 35 cfu/m3.

Conclusion
The study revealed high values of intraoperative airborne cfu exceeding recommended levels. Minimizing the number of door-openings and people present during surgery could be an effective strategy to reduce microbial air contamination in low- and middle-income settings