Ishii 2016.

Methods	RCT, parallel design, single‐centre
Participants	Total number of randomized participants: 59 Inclusion criteria ASA I to II, ≥ 70 years of age Exclusion criteria History of dementia, depression, alcoholism, and liver cirrhosis History of using benzodiazepine, major tranquillizers, or steroids An ineffective postoperative analgesia via epidural anaesthesia Allergic reactions to local anaesthetics Type of surgery: elective gastrectomy, colectomy, or rectectomy Baseline characteristics TIVA group Age, mean (SD): 77.3 (± 4.6) years Gender, M/F: 20/9 ASA grade: not reported Inhalational maintenance group Age, mean (SD): 76.5 (± 4.5) years Gender, M/F: 20/10 ASA grade: not reported Country: Japan Setting: single‐centre
Interventions	TIVA group Participants: n = 29; 0 losses Induction details: insertion of epidural catheter, then induction with propofol 1 mg/kg to 1.5 mg/kg Maintenance details: propofol to maintain BIS 40 to 60 Other information: intraoperative analgesia given with injection of fentanyl or continuous infusion of 0.25% ropivacaine (6 mL/hour) Inhalational maintenance groups Participants: n = 30; 0 losses Induction details: insertion of epidural catheter, then induction with propofol 1 mg/kg to 1.5 mg/kg Maintenance details: sevoflurane to maintain BIS 40 to 60 Other information: analgesia same as TIVA group
Outcomes	Incidence of postoperative delirium (using CAM)
Notes	Funding/declarations of interest: not reported Study dates: July 2009 to December 2010
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Participants were randomized to groups; no additional details.
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not feasible to blind anaesthetists to intervention groups
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Assessment done by ICU nurses blinded to group assignment
Incomplete outcome data (attrition bias) All outcomes	Low risk	No apparent losses
Selective reporting (reporting bias)	Unclear risk	Study authors do not report clinical trials registration. Not feasible to judge risk of selective outcome reporting
Other bias	Unclear risk	No other sources of bias noted. However, report is short with limited detail on anaesthetic regimen