Wang 2013.

Methods	Study design: randomized parallel groups Study dates: January 2010 to October 2011
Participants	Country: China Sex: female Age: aged 15 to 75 years, 52.9 (9.8), 53.3 (9.6) ASA: I‐III Procedure: breast cancer surgery including modified radical mastectomy, total mastectomy, lumpectomy, breast‐conserving surgery and breast reconstruction Study size: 920 enrolled, 908 completed study
Interventions	Randomized portion of anaesthetic: parts of TIVA: premedication (phencyclidine) vs placebo Intervention 2: premedication (N = 456) phencyclidine (PHC) 0.01 mg/kg Intervention 2: premedication (N = 452) placebo (saline) BIS‐guided total intravenous anaesthesia
Outcomes	Primary outcomes: awareness/wakefulness as defined using an awareness classification system (see Table 1) Quote: "The primary outcome was to evaluate the effect of PHC on intra‐operative awareness." Quote: "A committee of three experts, blinded to the study conditions, independently scrutinised all reported recollections...PHC group, none of the patients had recall of intra‐operative events (0%), saline group, five of 452 patients reported intra‐operative awareness (1.1%)"
Notes	Non‐randomized portion of anaesthetic: N2O no/parts of TIVA hypnotic (propofol TCI and bolus midazolam)/narcotics (bolus sufentanil): maintenance/muscle relaxants induction yes/maintenance PRN/BIS 40 to 60 General anaesthesia was induced by propofol (TCI) plasma target‐controlled infusion (a target plasma concentration of 3.5 to 4.5 lg/mL 1)/bolus midazolam (0.03 mg/kg 1)/bolus sufentanil (0.3 lg/kg 1)/intubation 0.2 mg/kg 1 cisatracurium BIS < 45. TCI adjusted maintain BIS 40 to 60/neuromuscular blockade: cisatracurium PRN Interventions: cardiovascular instability: if blood pressure deviated > 30% baseline value for > 5 min Correspondence to: ZM Tan Email: zmtan166@163.com ROB survey: we emailed zmtan166@163.com on 22 March 2015
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Random assignment of patients was established by computer‐generated codes. Allocation concealment was established by placing the randomisation sequence in consecutively numbered, opaque envelopes"
Allocation concealment (selection bias)	Unclear risk	Comment: unclear if sealed; await author's response to ROB survey
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "The PHC group received 0.01 mg.kg1 PHC intravenously, whereas the saline group patients received saline intravenously as placebo. Penehyclidine hydrochloride or saline solutions were prepared in a syringe by the first anaesthesiologist, who was also responsible for subject grouping. The PHC was diluted (1 mg in 1 ml) ...This second anaesthesiologist was also responsible for the anaesthetic manage"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "The third anaesthesiologist served as the postoperative interviewer. Awareness was defined as recall of intra‐operative events"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Patients’ data were not included if: two consecutive recorded BIS values were outside the target range 40–60; the time of surgery was longer than 10 h or shorter than 30 min; and patients required ephedrine or atropine because of circulatory instability. In all, data from 12 patients were not analysed (four in the PHC group, eight in the saline group), which left 908 patients’ data (456 in the PHC group and 452 in the saline group) available for analysis (Fig. 1)" Comment: Figure 1: PHC group: excluded 4: BIS < 40 N = 1, > 60 N = 1, ephedrine N = 2, atropine N = 0; saline group: excluded 8: BIS < 40 N = 3, > 60 N = 2, ephedrine N = 2, atropine N = 1; high‐risk awareness exclusions: BIS > 60 N = 1 for PHC and 2 for saline groups; 2% (1/460) vs 4% (2/460); since the saline group has increased awareness events and high‐risk awareness exclusions vs PHC group, there is no downgrade In addition, there was no significant difference between groups, Peto OR 0.75 (0.17 to 3.32)
Selective reporting (reporting bias)	Low risk	Comment: awareness outcome part of inclusion criteria
Other bias	Unclear risk	Comment: no information