Effects of operating room ventilation on particle exposure and removal during general endotracheal anesthesia

The operating room (OR) ventilation system is a primary method for reducing particle exposure in the OR. However, most ventilation studies in operating rooms were conducted using computational fluid dynamics (CFD) models, which may not be able to predict the complexity of real operating conditions. In this study, we recruited 40 patients undergoing general endotracheal anesthesia in a total of 13 operating rooms. We tested the effectiveness of OR ventilation on mitigating patient and nebulizer-generated particles during the preoxygenation, induction, and intubation phases of care. Sampling locations were selected close to the patient's face (reference), physician's head area, and medical assistant's standing location. A total of six sampling sessions characterizing patient and healthcare worker activities were included. We observed a significantly higher number of particles during endotracheal intubation compared to preoxygenation with deep breathing and coughing, suggesting potential disruptive effect of surgical activities (i.e., intubation) on airflow, which affected particle concentration. Particle decay rates measured at all three locations (reference 50 ± 20 h-1; physician 46 ± 22 h-1; medical assistant 33 ± 21 h-1) were considerably higher than the regulated operating room air exchange rate of 20 h-1, indicating highly effective overall ventilation function. Nevertheless, healthcare workers should still be cautious about particle exposure risks in operations that generate large number of particles. Results from this study reflect the effectiveness of OR ventilation on particle mitigation in real-world scenario and may facilitate the validation of future CFD studies as well as the establishment of effective OR regulation guidelines to protect healthcare workers from particle exposures. •Operating room (OR) ventilation mitigates particle exposure but the effectiveness under real-world conditions is unclear.•This study involved 40 patients and assessed the ventilation during anesthesia in 13 ORs.•Significantly higher particle levels were detected during intubation indicating disruptive effect of surgical activities.•Particle decay rates exceeded the regulated air exchange rate in OR suggesting effective ventilation.