Gao 2018.

Study characteristics
Methods	Design: RCT Date of study: July 2017 Power calculation: not reported Inclusion criteria: aged 65+, with silent lacunar infarct, who underwent spinal surgery in July 2017 (at Third Hospital of Hebei Medical University) Exclusion criteria: MMSE score of less than 24 or dementia, due to various aetiologies, preoperative delirium, history of neurological or mental illness, current use of tranquillisers or antidepressants, history of an endocrine or metabolic disorder, recent use of glucocorticoids or other hormones, suffering from infections or chronic inflammatory conditions, intake of anti‐inflammatory drugs, unwillingness to complete the experimental procedures, inability to communicate in the preoperative period (language barrier or severe hearing or visual impairment), and alcohol or drug dependence.
Participants	Sample size: 64 Country: China Setting: hospital ‐post surgery at Third Hospital of Hebei Medical University (China) Age: mean age 71 (SD = 5) in the intervention group, mean age 73 (SD = 4) in the control group Sex: male, 15, 47% in the intervention group, male, 18, 56% in the control group Co‐morbidity: no significant differences for the American Society of Anaesthesiologists (physical status) and for BMI Dementia: excluded Frailty: not reported
Interventions	Intervention: transcutaneous electrical acupoint stimulation: TEAS (disperse‐dense waves; frequency, 2/100 Hz) on acupoints Hegu and Neiguan of both sides starting from 30 minutes before induction of anaesthesia until the end of surgery, and the intensity was the maximum current that could be tolerated. Control: in the control group, electrodes were placed on the same acupoints before anaesthesia induction, but no current was given.
Outcomes	Outcomes reported ‐Incident delirium using CAM‐ICU/RASS Outcomes from study not reported: none Frequency of outcomes assessment: assessed on day of surgery and twice daily on the 3 days following surgery
Notes	Funding source: National Natural Science Foundation of China (81771134), Natural Science Foundation of Hebei Province (H2018206305), and Hebei Provincial Government Funded Clinical Talents Cultivation and Basic Research Projects (361005). Declarations of interest: authors report no conflicts of interest. Delirium excluded at enrolment Statistically significant imbalance in administration of Propofol and Remifentanil with those in the control group receiving more of both. May be related to observed rates of delirium.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Divided into two groups using a random number table
Allocation concealment (selection bias)	Unclear risk	No information provided around how allocations were concealed.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding of participants unclear as intervention delivered while under anaesthesia and electrodes places for both groups. Blinding of personnel not described, but intervention would need to be actively administered.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Delirium assessment conducted by researchers blinded to group assignment
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants included in the analysis
Selective reporting (reporting bias)	Unclear risk	Insufficient information to assess as no published protocol
Other bias	Low risk	No evidence of other bias