Table 4 Risk of bias determined using the Cochrane Risk of Bias Tool 2.0

Randomisation

Low

‘When informed consent is obtained, the patient will be randomized at the outpatient clinic. Randomization is performed per center by an internet randomization module maintained by coordinators at the VUmc.’

Deviations from intended interventions

High

‘Patients, and investigators undertaking interventions, assessing outcomes, and analysing data were not masked to group assignment.’

‘Open oesophagectomy involved … the lateral decubitus position with double tracheal intubation and lung block… Minimally invasive oesophagectomy was performed … in the prone position … with single-lumen tracheal intubation…’

Missing outcome data

Low

All randomised patients included in intention-to-treat analysis.

Measurement of outcome

High

‘Patients, and investigators undertaking interventions, assessing outcomes, and analysing data were not masked to group assignment.’

Imaging and sputum culture decisions made by team providing postoperative care for patient, not blinded to treatment allocation.

Selection of reported result

High

Protocol: ‘The primary endpoint of this study concerns the respiratory complications (i.e. infections) within two weeks after the operation. This is categorized as: grade 1) initial respiratory after operation with continued mechanical ventilation; grade 2) after successful detubation, clinical manifestation of respiratory infection caused by (broncho) pneumonia, confirmed by thorax X-ray or CT scan … and a positive sputum culture; and grade 3) other thoracic infections…’

Report: the primary outcome was postoperative pulmonary infection, defined as clinical manifestation of pneumonia or bronchopneumonia confirmed by thoracic radiographs or CT scan … and a positive sputum culture …’

Overall

High