Influence of a local ventilation system on patient and personnel protection in operating rooms

Ventilation systems in operating rooms have high importance, as they simultaneously are important for patient and personnel safety. However, conventional ventilation systems laminar air flow and mixing ventilation show disadvantages, e.g., the first leads to discomfort of the staff because of high draught risks and the latter improves lateral transport of contaminations. In this study, a concept that introduces additional air inlets for local horizontal ventilation in the vicinity of the operation table combined with these conventional systems is tested in experiments. The impact on the removal of bacteria originating from the surgical staff and surgical smoke that is emitted during electrosurgical procedures with surrogate particles as well as thermal comfort of the staff and heat flux of the patient were experimentally assessed in a full-scale research operating room. It was shown that the concentrations of contaminations were reduced by more than one order of magnitude for surgical smoke and two orders of magnitude for airborne germs in the proximity of the local air inlet, compared to reference cases without local ventilation. Moreover, a risk of cross-contamination from the surgical micro-environment to the peripherical area was formed due to the horizontal airflow. The heating system of the patient simulators surface consumed 13 % more power for LAF and 29 % for TMV compared to the reference cases, increasing the risk of perioperative hypothermia. The thermal comfort of the surgical staff was not significantly affected by the local ventilation system.