Objective: To study the effect of a portable HEPA-filtered air exhaust system (Stackhouse Freedom Surgical Helmet System) on airborne microbial contamination in a modern conventional operating room.
Design and Setting: Microbial air sampling was done with a two-stage Anderson sampler at the wound site during 46 total joint replacements. All operations were performed by the same surgeon in the same operating room at a large community hospital.
Results: In 18 cases done without air exhaust hoods, the number of bacterial and fungal colony-forming units (CFU) ranged from 0.6 to 11.7 (mean, 3.6). Air sampling during 28 operations with the operating team in air exhaust hoods revealed a mean of 3.6 CFU (range, 0 to 11.4). Bacterial CFU averaged 3.4 without hoods and 3.2 with exhaust hoods. Coagulase-negative staphylococci were the most common isolates (48% of isolates with hood, 55% without hood). No infections occurred.
Conclusion: We conclude that these air exhaust hoods did not lower airborne microbial contamination detectable with this air sampling method, as compared to standard head cover and mask, in a modern conventional operating room.