Prevention of COVID-19 infection in the delivery room by assessing smoke test visualization of exhaled air

The principal route of the coronavirus disease 2019 (COVID-19) infection is through the inhalation of respiratory droplets and aerosols. To date, there are no reports on the control of aerosol-mediated infections during vaginal delivery. This study aimed to visualize the airflow in a delivery room and use this information to develop infection control measures. A tracheal intubation practice manikin was used for the experiment. Smoke was generated using fog liquid and a fog machine. Smoke was collected in a plastic bag connected to the lower pharynx of the manikin via a conduit. Exhaled airflow was visualized by irradiating exhaled smoke with a laser beam. We visualized the aerosol flow from the mouth and nose of the manikin by compressing a plastic bag filled with smoke. We performed a smoke test to check the expiratory flow and accordingly modified the delivery room in two ways: the head side of the delivery table was surrounded with a plastic sheet, and the exhaust pipe was passed through the vinyl sheet to the exhaust port. After these modifications, we managed 18 vaginal deliveries in parturient women with COVID-19, with no related infections among the babies or staff. With emerging infectious diseases, such as COVID-19, the route of infection may be unclear and determining appropriate infection control measures can be difficult. By considering the characteristics of the virus and implementing appropriate infection control measures, we can safely manage high-risk vaginal deliveries.