Air circulation in a gastrointestinal light source box and endoscope in the era of SARS-CoV-2 and airborne transmission of microorganisms.

The role that air circulation through a gastrointestinal endoscopy system plays in airborne transmission of microorganisms has never been investigated. The aim of this study was to explore the potential risk of transmission and potential improvements in the system.  We investigated and described air circulation into gastrointestinal endoscopes from Fujifilm, Olympus, and Pentax.  The light source box contains a lamp, either Xenon or LED. The temperature of the light is high and is regulated by a forced-air cooling system to maintain a stable temperature in the middle of the box. The air used by the forced-air cooling system is sucked from the closed environment of the patient through an aeration port, located close to the light source and evacuated out of the box by one or two ventilators. No filter exists to avoid dispersion of particles outside the processor box. The light source box also contains an insufflation air pump. The air is sucked from the light source box through one or two holes in the air pump and pushed from the air pump into the air pipe of the endoscope through a plastic tube. Because the air pump does not have a dedicated HEPA filter, transmission of microorganisms cannot be excluded.  Changes are necessary to prevent airborne transmission. Exclusive use of an external CO pump and wrapping the endoscope platform with a plastic film will limit scatter of microorganisms. In the era of pandemic virus with airborne transmission, improvements in gastrointestinal ventilation systems are necessary to avoid contamination of patients and health care workers.