Comparison of operating room air distribution systems using the environmental quality indicator method of dynamic simulated surgical procedures.

Background: Ensuring aseptic airborne environments for sterile fields and back instrument tables in operating rooms (ORs) is crucial to reducing microbial and particle contamination during surgery. Configurations of in-ceiling air delivery mechanisms impact the effectiveness of the system at eliminating contamination in critical zones.

Methods: The environmental quality indicator method was used to assess airborne environments in ORs equipped with a single large diffuser (SLD), a multidiffuser array (MDA), or a 4-way throw diffuser during dynamic, simulated surgical procedures. Environmental quality indicators measured included particles, microbes, carbon dioxide, velocity, humidity, and temperature at 26 air changes per hour.

Results: SLD ORs performed better than MDA ORs and 4-way throw diffuser ORs at removing microbes and carbon dioxide from the sterile field (P < .05). SLD ORs had higher velocity and lower temperature over the sterile field than the other 2 ORs (P < .05). MDA ORs had lower total particle counts than the other ORs (P < .05). The sterile fields in all ORs were cleaner than the respective back instrument tables (P < .05).

Conclusions: Air delivery systems that eliminate blockages to uniform airflow directly over sterile zones, such as boom mounts and access panels, and deliver unidirectional, downward flow of clean filtered air provided a cleaner airborne environment within the sterile field. Expansion of air delivery systems to include areas outside the sterile field, where other surgical aides reside, may further reduce contamination within critical zones.