The SARS-Cov-2 disease disrupted essential hospital procedures, such as gastrointestinal (GI) endoscopy, due to concerns about air transmission and the risk of exposing health care workers. With the spread of the pandemic, air transmission was considered as the main source of SARS-Cov2 transmission. This raised the problem of transmission by aerosolization of viral particles in operating rooms as well as endoscopy units. This is in line with the known airborne transmission of many other respiratory viruses. The risk of SARS-Cov-2 transmission during GI endoscopy was initially reduced by controlled measures, involving personal protections (mask…), restricted access to endoscopy rooms, and detection of infected patients. Gastrointestinal endoscopy generates aerosols, which may carry viruses. In addition, the endoscopy system may facilitate the diffusion of virus particles or fomites considering the forced-air cooling system used to maintain a stable temperature inside the box (25°C). The volume of air that goes through the light source box is high (240-300 m 3 for a 1-h period). Moreover, the light system contains an air pump to inflate air inside the gut lumen. In order to isolate people from hazard, different levels of protection and solutions to avoid airborne transmission of microorganisms should be proposed, such as the reinforcement of personal protective equipment, the change in the way people work and engineering control of the risk.

Background and study aims Evidence for the modes of transmission of SARS-CoV-2 remains controversial. Recently, the potential for airborne spread of SARS-CoV-2 has been stressed. Air circulation in gastrointestinal light source boxes and endoscopes could be implicated in airborne transmission of microorganisms. Methods The ENDOBOX SC is a 600 × 600 mm cube designed to contain any type of machine used during gastrointestinal endoscopy. It allows for a 100-mm space between a machine and the walls of the ENDOBOX SC. To use the ENDOBOX SC, it is connected to the medical air system and it provides positive flow from the box to the endoscopy room. The ENDOBOX SC uses medical air to inflate the digestive tract and to decrease the temperature induced by the microprocessors or by the lamp. ENDOBOX SC has been investigated in different environments. Results An endoscopic procedure performed without ventilation was interrupted after 40 minutes to prevent computer damage. During the first 30 minutes, the temperature increased from 18 °C to 31 °C with a LED system. The procedure with fans identified variations in temperature inside the ENDOBOX SC from 21 to 26 °C (± 5 °C) 1 hour after the start of the procedure. The temperature was stable for the next 3 hours. Conclusions ENDOBOX SC prevents the increase in temperature induced by lamps and processors, allows access to all necessary connections into the endoscopic columns, and creates a sterile and positive pressure volume, which prevents potential contamination from microorganisms.