Trial outcomes will only be based on routinely available data. Patients will not undergo any additional investigations for trial purposes. Primary outcome measure The primary outcome is any one of the following COVID-19 specific, inpatient, postoperative pulmonary complications (definitions are given in an Appendix in the protocol and through brief online training): • Pneumonia • Acute respiratory distress syndrome (ARDS) • Death Definitions for each outcome are provided in the protocol. The components of the composite outcome have all been internationally validated. The feasibility of collecting these endpoints within routine care pathways has been demonstrated by our RECON cohort (11,500 patients, 4 countries).

Trial outcomes will only be based on routinely available data. Patients will not undergo any additional investigations for trial purposes. Primary outcome measure The primary outcome is any one of the following COVID-19 specific, inpatient, postoperative pulmonary complications (definitions are given in an Appendix in the protocol and through brief online training): • Pneumonia • Acute respiratory distress syndrome (ARDS) • Death Definitions for each outcome are provided in the protocol. The components of the composite outcome have all been internationally validated. The feasibility of collecting these endpoints within routine care pathways has been demonstrated by our RECON cohort (11,500 patients, 4 countries).