In the context of the COVID-19 pandemic this study showed feasibility and efficacy of systematic preoperative screening for SARS-CoV-2 by chest CT and RT-PCR on nasopharyngeal swabs. This screening strategy allowed performing safely the majority of scheduled oncological interventions.
International guidelines recommend limiting surgical care in the context of the ongoing SARS-CoV-2 pandemic but most of them are not evidence-based (1) . Among those recommendations preoperative SARS-CoV-2 screening is key to select optimal surgical candidates (2), but its impact on surgical outcomes is unknown.
The aim of this study was to assess the impact of a systematic preoperative SARS-CoV-2 screening strategy including chest computed tomography (CT) and real-time reverse transcriptase polymerase chain reaction (RT-PCR) on short-term postoperative outcomes at a tertiary center.
This is a retrospective analysis of all consecutive patients undergoing elective and emergency digestive surgery at Croix Rousse University Hospital, Lyon, France during the early phase of the SARS-CoV-2 outbreak in France starting from the date of implementation of systematic SARS-CoV-2 screening strategy on 2020-03-24 until 2020-04-10.
Patients scheduled for elective surgery were reassessed at a multidisciplinary team meeting and treatment decision were made according to the individual surgical and non-surgical risk factors. For instance, major interventions such as extended hepatectomy or oesophagectomy in frail patients with long expected ICU stays were postponed if possible.
The surgical department was substantially reorganized to guarantee optimal control of patient in-and outflow. Three separate surgical units were set-up: one for all elective surgery in SARS-CoV-2 negative patients, one for SARS-CoV-2 positive patients and a third unit specifically dedicated to the liver transplantation program. All three surgical units were strictly separated and attended by different medical and paramedical staff.
A corner stone of the reorganization strategy was the implementation of a systematic SARS-CoV-2 screening by three different tests: (a) a questionnaire on symptoms which may have occurred prior to hospitalization and a clinical examination on hospital arrival, (b) nasopharyngeal swabs with a RT-PCR and (c) a chest CT 24 hours before surgery. Surgery was only performed if all three tests were negative. Patients who were admitted through the emergency department were screened in the emergency room using the same protocol. Patients with unknown SARS-CoV-2 status were admitted to the SARS-CoV-2 positive surgery unit and if surgery could not be delayed, patients were operated in a dedicated operating room.
No routine postoperative SARS-CoV-2 screening was performed, and testing was only guided by clinical symptoms. Follow-up calls after hospital discharge were performed by one of the study investigators to screen for COVID-19 occurrence after hospital discharge.
The primary study endpoint was major postoperative complications assessed by the Clavien-Dindo classification. Secondary outcomes included preoperative SARS-CoV-2 screening results, hospital stay, COVID-19 occurrence after hospital stay and assessment of reduction in operative room capacity. RT-PCR testing was performed on nasopharyngeal swabs. Chest CT were interpreted according to the guidelines from the European Society of Radiology (ESR) and the European Society of Thoracic Imaging (ESTI).
A total of 31 patients were admitted for elective and emergency surgery during the study period predominantly from home (59%) with a median age of 64 (58-70) years. Except for smoking history, respiratory comorbidities were rare whereas 19% of patients had a history of cardiovascular disease.
Detailed characteristics are listed in Table 1 .
One patient with mild cough presented signs of COVID-19 pneumonia at chest CT, and diagnosis of SARS-CoV-2 was confirmed on RT-PCR. The patient had already received a biliary drainage and the initially planned pancreaticoduodenectomy could thus be safely delayed. A second patient presented to the emergency room for a perianal abscess and underwent nasopharyngeal swab.
He then refused to stay at hopsital and was discharged without chest CT. He was operated on the next day in the same-day surgery setting with a negative RT-PCR.
The main surgical indication in our cohort was oncological (58%) ( Table 2) . Only four patients required ICU surveillance after surgery as preoperatively planned. Overall median hospital stay was 6 (3-14) days. During hospital stay, 3 (10%) patients developed a severe complication (Clavien-Dindo >II). In detail, one patient developed a retro-gastric abscess on postoperative day 7 which was drained radiologically (IIIa). Two other patients developed multiorgan failure with the need of ICU treatment due to hemorrhage and septic shock (IVb).
No patient showed COVID-19 symptoms or was tested positive for SARS-CoV-2 after hospital discharge (median follow-up 15 (9-22) days).
We report outcomes in 31 patients admitted to our surgical department of a tertiary center Several studies support the importance of chest CT to identify SARS CoV-2 infected patients in addition to RT-PCR. (4, 5) . A recent study showed that in 601 patients with a positive RT-PCR the sensitivity of chest CT was 97% (4). In addition, 93% of patients with initially negative RT-PCR already showed signs of COVID-19 pneumonia on chest-CT and were later confirmed SARS CoV-2 on RT-PCR (4). In a retrospective study analyzing 120 cases with confirmed COVID-19, the authors identified 16 asymptomatic patients with signs of SARS CoV-2 pneumonia on chest CT and were later confirmed SARS CoV-2 positive on RT-PCR.(5) Of note, by applying this strategy we were able to diagnose one SARS-CoV-2 positive patient and consequently safely postponed surgical intervention.
This retrospective analysis has inherent limitations. First, the sample size is small and more data are required to confirm our results. Second, no routine postoperative screening by RT-PCR or chest CT was performed. However, no patient reported symptoms or adverse outcomes during the median follow-up of 15 days (9-22) which is longer than the expected incubation period of SARS-CoV-2.
Implementing routine postoperative RT-PCR and chest CT may additionally help to formally exclude postoperative infection with SARS-CoV-2.
In conclusion, our preliminary data show feasibility and efficacy of systematic preoperative screening for SARS-CoV-2 by chest CT and RT-PCR on nasopharyngeal swabs. This screening strategy allowed performing safely the majority of scheduled oncological interventions.
The authors declare no conflict of interest 