SARS-CoV-2 Prevalence in Laparoscopic Surgery Filters. Analysis in Patients with Negative Oropharyngeal RT-qPCR in a Pandemic Context: A Cross-Sectional Study (†)

Objective: Surgical societies of different specialties have lately demonstrated a growing concern regarding the potential risk of SARS-CoV-2 transmission during surgery, mainly via aerosols carrying SARS-CoV-2 particles during laparoscopy smoke evacuation. Since there is not sufficient scientific evidence to rule out this hypothesis, our study aimed to evaluate the prevalence of the appearance of SARS-CoV-2 genetic material in the in-filter membrane of the smoke filter systems, used in laparoscopic surgery, in a tertiary referral hospital during the peak phases of the pandemic. Methods: During the highest incidence of the pandemic outbreak, 180 laparoscopic smoke evacuation systems were collected from laparoscopies performed between April 2020 and May 2021 in University General Hospital of Castellón. As part of the safety protocol established as a result of the pandemic, an oropharyngeal reverse-transcription polymerase chain reaction (RT-PCR) was performed before surgery. We performed RT-qPCR tests for the detection and quantification of SARS-CoV-2 genetic material in the in-filter membranes extracted from the smoke evacuation systems. Results: We found two RT-qPCR positive in-filters from a sample of 128 patients with SARS-CoV-2-negative results in their oropharyngeal RT-qPCR, i.e., 1.6% (95% CI: 0.5–5.5%). From this estimation, the predictive posterior probabilities of finding n cases of negative oropharyngeal COVID-19 patients with positive filters increases with the increasing number of surgeries performed. Conclusions: This cross-sectional study provides evidence suggesting that airborne transmission of SARS-CoV-2 particles from smoke evacuation of aerosols carrying viral particles during laparoscopy should not be ruled out.