Tan 2009.

Methods	RCT, parallel design, single‐centre
Participants	Total number of randomized participants: 60 Inclusion criteria Undergoing abdominal surgery, > 60 years of age, ASA I to II Exclusion criteria Neurological abnormalities Regularly taking medication for neuropsychiatric disorders Type of surgery: abdominal surgery Baseline characteristics TIVA group Age, range: 60 to 81 years Gender: not reported ASA grade: not reported Inhalational maintenance group Age, range: 60 to 81 years Gender: not reported ASA grade: not reported Note: Study authors do not report a baseline characteristics table. Study authors report no differences between group in age, weight, height and general condition Country: China Setting: hospital
Interventions	TIVA group Participants: n = 30; 0 losses Induction details: propofol IV 1.5 mg/kg to 2 mg/kg, fentanyl 2 µg/kg to 4 µg/kg, vecuronium 0.1 mg/kg Maintenance details: propofol IV 100 µg/kg/min to 150 µg/kg/min, fentanyl and vecuronium as required Inhalational maintenance group Participants: n = 30; 0 losses Induction details: propofol IV 1.5 mg/kg to 2 mg/kg, fentanyl 2 µg/kg to 4 µg/kg, vecuronium 0.1 mg/kg Maintenance details: 1% to 2 % isoflurane, fentanyl and vecuronium as required
Outcomes	POCD, using MMSE before and after surgery (1, 6, 12, 24 and 48 hours after surgery) Intraoperative stress response HR MAP BIS
Notes	Funding/declarations of interest: not reported Study dates: not reported Note: study report is in Chinese. We have used Google translate for essential paragraphs. We noted that this study was reported by a single author and may not be the original study report; we checked the study details against other included studies for duplication but found no duplication
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	Unclear risk	No details
Incomplete outcome data (attrition bias) All outcomes	Low risk	No apparent loss of study participants
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 baseline characteristics table. Limited information in short report, and we noted that this study was reported by a single author