Experimental evaluation of airborne spread of contaminations in operating room air under laminar air flow and mixing ventilation

Surgical-site infections are a health risk for people undergoing surgery. Surgical-site infections can be triggered by the deposition of germs in the wound area. The operating room air is considered as an entry path for germs originating from the surgical staff. Surveillance studies show that the state-of-the-art concept laminar air flow does not lead to the lowest infection rates. To evaluate the removal efficiency of airborne germs quantitatively, this study aims to investigate the effect of the operating room airflow with different ventilation systems experimentally. Realistic personnel simulators and a generic particle source were used to surrogate the emission of airborne germs by surgical staff in the research operating room. Based on this, the behavior of different particle sizes, number of surgical staff and the influence of surgical lights were regarded. Particle counting at critical areas was used to measure the spread of particles in the operating room air. It was found that small particles travel to further positions than large particles. Laminar air flow does not provide low particle concentrations at the wound area and is highly influenced by surgical lights. Turbulent mixing ventilation leads to an improved transport of particles in areas further away and can therefore favor cross contamination. • Experimental Comparison of OR ventilation concepts • Particle measurements in realistic test environment • No clear benefit of any ventilation system • Influence of particle size on the risk for cross-contamination • Significant influence of surgical lights on particle transport under LAF