Our study shows, as others , that it is possible to avoid dispersion of potentially virus-bearing aerosol into the ambient air of operating rooms by use of a simple, easily assembled, cost-effective and readily available filter system.
At present, there are no data that prove 2019-nCov can be transmitted to operating room personnel when the pneumoperitoneum is released at the end of the operation, or inadvertently during exchange of instruments, dislocation of ports, or before specimen retrieval. Likewise, no data are available about the presence of 2019-nCoV in peritoneal fluid.
There is increasing evidence that 2019-nCoV is present in stool . Around 2–10% of patients with COVID-19 have gastrointestinal symptoms such as diarrhea, abdominal pain, and vomiting .
For these reasons, COVID-19 positive or suspected patients needing emergency surgery entailing perforation or intentional opening of the intestinal tract (oncological procedures) should be considered as a potential source for virus dissemination.
The main concern, however, is to eliminate any possible contamination in the CO2 used for creation of pneumoperitoneum. One very recent paper indicated that 2019-nCoV remains viable in aerosols for at least 3 h and on surfaces up to 2 or 3 days . However, whether these experimental results in a Goldberg drum are reproducible for laparoscopic surgery in the human remains to be shown, and the conclusions of the authors are cautious “… aerosol and fomite transmission of SARS-CoV-2 is plausible”. Should this be the case, the HME filters have a bacterial and viral filtration efficiency of ≥ 99.999% . Including such easily assembled filtering systems as described above can offer a complete viral filtration during intra- and postoperative release of pneumoperitoneum.
Of note, the length of the connection to the filter could affect the efficiency. For this reason, we strove to find the shortest connectors available in both systems. Our first system, although similar to the recently described EAES system , was developed independently, but used slightly shorter connectors. Our second system was developed with the intention to overcome the relatively slow rate of smoke evacuation of the first, in particular for operations requiring extensive dissection and prolonged use of cautery and/or energy devices and uses connecting tubes that are shorter and, above all, larger than the first.
For mechanical reasons, the use of the second system was effectively felt to improve operative field visibility quickly and thus shorten overall operation duration. Likewise, high volumes of smoke/aerosolized tissue, as generated during lengthy operations, are managed adequately.
In order to obtain a systematic use and the standardization of the procedure, we suggest to prepare dedicated kits, ready for use. This strategy has been easily accepted by the OR staff of our hospitals, with a high degree of compliance. Finally, the use of these systems should increase the awareness of the entire OR staff about the problem of surgical plumes and their diffusion.
Additional preventive measures are of interest.
Low pressure pneumoperitoneum (LPP) [1,2,3, 5, 10,11,12] might reduce uncontrolled exit of aerosol during the change of instruments. LPP should also reduce the pressure on the diaphragm, especially important in patients with compromised respiratory function . We, as others [5, 11,12,13,14,15, 21], strongly recommend to reduce the intensity and duration of use of energy devices with increased smoke production, careful insertion/extraction of the instruments, and accurate use of aspiration devices during laparoscopic procedures. Likewise, we recommend to oversee that a perfect orthogonal axis of instruments during insertion is maintained, minimizing the risk of inadvertent escape of CO2 through the trocar shaft valve.