It is established that coronaviruses are transmitted most through aerosols produced when an infected individual coughs or sneezes. Although there is no clear evidence of person-to-person airborne transmission, it is possible that part of this component could be due to microscopic respiratory droplets at short to medium distances (up to several meters, or room scale) and deposits from respiratory droplets on surfaces.
However, recent studies revealed that infected patients can potentially be a source of the virus not only through respiratory but also fecal–oral or body fluid routes, raising also the theoretical possibility of bloodborne transmission. Based on these arguments, the possibility has also been raised of some equipment that could be a new source of transmission, like the membranes used for extracorporeal oxygenation, which act the same as lungs and also have a direct contact with the blood.
In summary, although there is no evidence-based research to support that membrane oxygenators used during CPB could be another source of SARS-CoV-2 transmission, simple precautions like the vacuum suction or filtration should be recommended, until we assure it is not necessary.