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

After the outbreak of COVID-19, additional protocols have been established to prevent the transmission of the SARS-CoV-2 from the patient to the health personnel and vice versa in health care settings. However, in the case of emergency surgeries, it is not always possible to ensure that the patient is not infected with SARS-CoV-2, assuming a potential source of transmission of the virus to health personnel. This work aimed to evaluate the presence of the SARS-CoV-2 and quantify the viral load in indoor air samples collected inside operating rooms, where emergency and scheduled operations take place. Samples were collected for 3 weeks inside two operating rooms for 24 h at 38 L/min in quartz filters. RNA was extracted from the filters and analyzed using RT-qPCR targeting SARS-CoV-2 genes E, N1 and N2 regions. SARS-CoV-2 RNA was detected in 11.3% of aerosol samples collected in operating rooms, despite with low concentrations (not detected at 13.5 cg/m3 and 10.5 cg/m3 in the scheduled and emergency operating rooms, respectively). Potential sources of airborne SARS-CoV-2 could be aerosolization of the virus during aerosol-generating procedures and in open surgery from patients that might have been recently infected with the virus, despite presenting a negative COVID-19 test. Another source could be related to health care workers unknowingly infected with the virus and exhaling SARS-CoV-2 virions into the air. These results highlight the importance of reinforcing preventive measures against COVID-19 in operating rooms, such as the correct use of protective equipment, screening programs for health care workers, and information campaigns. IMPORTANCE Operating rooms are critical environments in which asepsis must be ensured. The COVID-19 pandemic entailed the implementation of additional preventative measures in health care settings, including operating theaters. Although one of the measures is to operate only COVID-19 free patients, this measure cannot be always implemented, especially in emergency interventions. Therefore, a surveillance campaign was conducted during 3 weeks in two operating rooms to assess the level of SARS-CoV-2 genetic material detected in operating theaters with the aim to assess the risk of COVID-19 transmission during operating procedures. SARS-CoV-2 genetic material was detected in 11% of aerosol samples collected in operating rooms, despite with low concentrations. Plausible SARS-CoV-2 sources have been discussed, including patients and health care personnel infected with the virus. These results highlight the importance of reinforcing preventive measures against COVID-19 in operating rooms, such as the correct use of protective equipment, screening programs for health care workers and information campaigns.

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.