Preoperative nasopharyngeal swab testing and postoperative pulmonary complications in patients undergoing elective surgery during the SARS-CoV-2 pandemic

Collaborative, COVIDSurg

Introduction: Surgical services are preparing to scale-up in areas affected by COVID-19. This study aimed to evaluate the association between preoperative SARS-CoV-2 testing and postoperative pulmonary complications in patients undergoing elective cancer surgery. Method(s): International cohort study including adult patients undergoing elective surgery for cancer in areas affected by SARS-CoV-2 up to 19 April 2020 (NCT04384926). Patients suspected preoperatively of SARS-CoV-2 infection were excluded. The primary outcome measure was postoperative pulmonary complications at 30 days after surgery. Preoperative testing strategies were adjusted for confounding using mixed-effects models. Result(s): Of 8784 patients (432 hospitals, 53 countries), 2303 patients (26.2%) underwent preoperative testing: 1458 (16.6%) had a swab test, 521 (5.9%) CT only, and 324 (3.7%) swab and CT. The overall pulmonary complication rate was 3.9% and SARS-CoV-2 infection rate was 2.6%. After risk adjustment, only a nasopharyngeal swab test (adjusted odds ratio 0.68, 95% confidence interval 0.68-0.98, p=0.040) was associated with lower rates of pulmonary complications. Swab testing remained beneficial before major surgery and in high SARS-CoV-2 population risk areas but not before minor surgery in low incidence areas. For a swab test, the number needed to test to prevent one pulmonary complication increased across major and minor surgery in high incidence areas (18 and 48 respectively), and major and minor surgery in low incidence areas (73 and 387 respectively). Discussion(s): Preoperative nasopharyngeal swab testing was beneficial before major surgery and in high SARS-CoV-2 incidence areas. There was no proven benefit of swab testing before minor surgery in low incidence areas.Copyright © 2020