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

Abstract

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.

Genetic Load of SARS-CoV-2 in Aerosols Collected in Operating Theaters

“…In relation to the filters derived from laparoscopy, although previous studies carried out with the same methodology had led to detection ( 13 ), no genetic material could be detected in any of the laparoscopic filters available from the dates that positive air samples were detected. Therefore, it was not possible to compare the results obtained through the different types of filters.…”

“…Because the virus might be embedded in human tissue of infected patients ( 32 , 33 ) and there is likelihood of it being aerosolized during the surgical procedure, the opening of the abdominal cavity of asymptomatic patients with a previous negative PCR test might be a plausible source of the detected levels. Laparoscopy surgery could be another possibility of transmission of the virus to the indoor air, although considered very unlikely ( 13 , 38 , 39 ). Likewise, aerosol-generating procedures, such as induction of anesthesia and intubation ( 40 ) might be another possible source of SARS-CoV-2 RNA airborne.…”

“…When the operations performed in the selected operating rooms led to the availability of laparoscopy filters, these were collected by health personnel and delivered to the research staff alongside the corresponding daily aerosol samples. The sampling of laparoscopy filters followed the same procedure described in Llueca et al ( 13 ). Laparoscopy filters were stored at −80°C until analysis.…”

“…SARS-CoV-2 RNA detection by RT-qPCR was performed as previously described ( 13 , 50 ). Briefly, presence of SARS-CoV-2, was determined using the 2019-nCoV RUO Kit (Integrated DNA Technologies) by specific amplification and FAM-probe detection of N1 and N2 regions of the nucleocapsid genes, validated by the US Centre for Disease Control prevention and the envelope gene E, validated by the Charité Berlin Institute of Virology (Berlín, Germany) ( 51 ).…”

“…In fact, higher levels of SARS-CoV-2 genetic material have been detected in hospital corridors than in rooms of infected patients, which has been attributed to the ventilation systems ( 12 ). Particularly in the University General Hospital of Castellón, the presence of SARS-CoV-2 has been detected in two laparoscopy filters from operating rooms with a prevalence of 1.5% ( 13 ).…”