Geng 2017.

Methods	RCT, parallel design, single‐centre
Participants	Total number of randomized participants: 150 Inclusion criteria ASA II to III, ≥ 65 years of age, sufficient level of education to be capable of completing neuropsychological tests Exclusion criteria History of allergy to anaesthetics Dialysis‐dependent renal failure Liver transaminase level < 1.5 times the normal value MMSE score ≤ 26 Pre‐existing diagnosis of schizophrenia or dementia Recent stroke Known disorder affecting cognition Mental dysfunction History of cerebral surgery Severe anxiety Recent history of alcohol abuse History of chronic opioid or other psychotropic drug use Type of surgery: laparoscopic cholecystectomy Baseline characteristics TIVA group Age: not reported Gender, M/F: 20/30 ASA grade: ASA II: 35; ASA III: 15 Inhalational maintenance group (isoflurane) Age: not reported Gender, M/F: 18/32 ASA grade: ASA II: 33; ASA III: 17 Inhalational maintenance group (sevoflurane) Age: not reported Gender, M/F: 22/28 ASA grade: ASA II: 31; ASA III: 19 Country: China Setting: hospital
Interventions	TIVA group Participants: n = 50; 0 losses Induction details: 5 minutes of pre‐oxygenation, then midazolam 0.05 mg/kg, fentanyl 4 µg/kg, rocuronium 0.6 mg/kg. TCI 3.0 µg/kg propofol Maintenance details: propofol with target concentration 2.5 µg/mL to 3.0 µg/mL. Remifentanil 0.2 µg/kg/min to 0.3 µg/kg/min. To maintain BIS 40 to 50 Other information: all patients given crystalloids as required. All patients were given flurbiprofen 100 mg and granisetron 3 mg at beginning of operation, and 0.25% ropivacaine via local infiltration for postoperative analgesia Inhalational maintenance groups Participants: n = 50; 0 losses Induction details: 5 minutes of pre‐oxygenation, then midazolam 0.05 mg/kg, fentanyl 4 µg/kg, rocuronium 0.6 mg/kg. TCI 3.0 µg/kg propofol Maintenance details: isoflurane 1.0 MAC to 1.5 MAC. Remifentanil 0.2 µg/kg/min to 0.3 µg/kg/min. To maintain BIS 40 to 50 Other information: fluids and analgesics same as TIVA group Inhalational maintenance groups Participants: n = 50; 0 losses Induction details: 5 minutes of pre‐oxygenation, then midazolam 0.05 mg/kg, fentanyl 4 µg/kg, rocuronium 0.6 mg/kg. TCI 3.0 µg/kg propofol Maintenance details: sevoflurane 1.0 MAC to 1.5 MAC. Remifentanil 0.2 µg/kg/min to 0.3 µg/kg/min. To maintain BIS 40 to 50 Other information: fluids and analgesics same as TIVA group
Outcomes	POCD on postoperative day 1 and 3 (using MMSE, vision test, the Digit Symbol Substitution Test, the Cumulative test, digit span, forward and backward, Trail Making Test Part A, the RAVLT, Grooved Pegboard Test (dominant and non‐dominant hand)). POCD defined as decline > 20% in at least 2 tests compared to baseline Plasma concentrations or protein biomarkers of POCD Proinflammatory markers Duration of anaesthesia and emergence times Use of vasoconstrictors Hypotension (number of participants, number of episodes, and duration)
Notes	Funding/declarations of interest: no funding and authors declare no conflicts of interest Study dates: December 2010 to June 2011
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Use of a computer‐generated random number table
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	A blinded anaesthetist evaluated cognitive scores
Incomplete outcome data (attrition bias) All outcomes	Low risk	No losses
Selective reporting (reporting bias)	Unclear risk	Retrospective clinical trials registration (ChiCTR‐OCC‐11001411). Not feasible to assess risk of selective reporting bias
Other bias	Unclear risk	Some differences in duration of anaesthesia, surgery times, and time to emergence from anaesthesia. We were not certain whether these differences were clinically significant. Also note that no ages were reported in baseline characteristics