Sato 2016.

Methods	RCT with parallel groups Approved by the ethics committee Written informed consents obtained Site: Yokohama City University Hospital Setting: university hospital Dates of data collection: October 2008 to September 2009 UMIN‐CTR: UMIN000021371 (3 July 2016); retrospectively registered
Participants	28 participants aged 20‐85 years undergoing hepatectomy Exclusion criteria: ASA physical status ≥ III, pre‐existing lung disease, tumour in the portal vein or inferior vena cava, requirement of bile duct or gastrointestinal tract repair, or requirement of additional surgical procedures other than hepatectomy
Interventions	Treatment group: tidal volume 6 mL/ kg (predicted body weight) (n = 14) Control group: tidal volume 12 mL/ kg (predicted body weight) (n = 14)
Outcomes	Relevant to this review Need for postoperative invasive ventilation between discharge from the postoperative care unit and 7 days after the surgery Hospital length of stay Others Haemodynamic parameters Acid–base status Oxygenation Interleukin‐8 in epithelial lining fluid
Notes	Funding: supported by the Center for Advanced Medical Promotion of the Yokohama City University Graduate School of Medicine (grant number: 07‐021) and the Grants‐in‐Aid for Scientific Research from the Japan Society for the Promotion of Science (grant number: 26462368) Declaration of interest: the authors declared that they had no competing interests. Volume per body weight: predicted body weight, no further details
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Assignment performed using a random number table by an investigator who was not involved in data collection and was notified to anaesthesiologists who were not involved in study using an envelope method.
Allocation concealment (selection bias)	Low risk	Assignment performed using a random number table by an investigator who was not involved in data collection and was notified to anaesthesiologists who were not involved in study using an envelope method.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not mentioned
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Investigators who collected the data and samples were blinded to the ventilation settings at any time of the experiment
Incomplete outcome data (attrition bias) All outcomes	Low risk	3 participants in the high tidal volume group were excluded because the operation was terminated before the completion of the study due to dissemination of tumour to the peritoneum.
Selective reporting (reporting bias)	Low risk	All results reported
Other bias	Low risk	Groups well balanced