Adams 1994.

Methods	Study design: double‐blind, randomized parallel groups Study dates: Quote: "ca. 1991 ‐ 1993" (ROB survey)
Participants	Country: Germany Sex: both Age: greater than 60; mean 68 ASA: I‐II Procedure: elective hip or knee replacement Study size: 37 (40 enrolled)
Interventions	Randomized portion of anaesthetic: parts of intravenous (IV) anaesthesia/induction/dissociative agent MCI Intervention 1: induction: 1 mg/kg S‐(+)‐ketamine; maintenance: 2 mg/kg/h S‐(+)‐ketamine (N = 20) Intervention 2: induction: 2 mg/kg racaemic ketamine; maintenance: 4 mg/kg/h racaemic ketamine (N = 20)
Outcomes	Primary outcomes: endocrine stress response ‐ recovery ‐ haemodynamic reaction Secondary outcome: awareness/wakefulness as defined using an awareness classification system (see Table 1): class 1 Quote: "no intraoperative awareness was reported." Quote: "After racaemic ketamine, 1 patient remembered a negative dream and 1 patient a positive dream. In the S (+)‐group, 1 positive dream was reported"
Notes	Non‐randomized portion of anaesthetic: parts of intravenous (IV) anaesthesia/N2O no: narcotics and/or hypnotics bolus/muscle relaxants induction yes/maintenance unclear Anaesthetic induction: 0.1 mg/kg midazolam + 0.5 mg atropine + 2 mg vecuronium + 1.5 mg/kg suxamethonium + 0.1 mg/kg vecuronium; anaesthetic maintenance: see above interventions Time of outcome determination: before discharge Method of determination: interview Translator: Lore Schultheiss adams.ha@mh‐hannover.de ROB survey response 24 January 2011
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "were investigated in a double‐blind, randomised design...." ROB survey response by Dr Adams: "Random by computer program with random numbers. Random numbers were opened not earlier then the study was finished"
Allocation concealment (selection bias)	Low risk	ROB survey response: "Double blinded study to patient and anaesthesist as well. Random numbers were opened not earlier then the study was finished"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	ROB survey response: "Patient, Anesthesiologist, Awareness outcome assessor (interviewer)"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	ROB survey response: "Patient, Anesthesiologist, Awareness outcome assessor (interviewer)"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Three patients in the ketamine‐racemate group showed severe arterial hypertension and were withdrawn from the study" Comment: imbalanced exclusion of 3/40 patients at high risk of awareness, but no significant difference between groups (3/20 vs 0/20): Peto OR 8.23 (0.81 to 84.07)
Selective reporting (reporting bias)	Low risk	ROB survey response: "Study protocol is not more available (study before 2000). The published record included all expected data and outcomes, no selective reporting. Non significant results were reported to show missing differences between the groups"
Other bias	Low risk	ROB survey response: "Limited number of patients"