Handa 2010.

Methods	Study design: Randomized control trial Study grouping: Parallel group
Participants	Baseline Characteristics 118 participants (men n = 38, women n = 80) Nitrous oxide‐free ‐ A Number randomized: 58 Number analysed: 58 Age (mean): NR % male: 18/58 = 31.0%* Type of surgery: Saggital split ramus osteotomy Nitrous oxide‐based ‐ A Number randomized: 60 Number analysed: 60 Age (mean): NR % male: 20/60 = 33.3%* Type of surgery: Saggital split ramus osteotomy Included criteria: Patients undergoing saggital split ramus osteotomy between August 2008 ‐ April 2009 Excluded criteria: History of alcoholism, substance misuse, psychiatric disorders, disorders which may affect metabolism of anaesthetic drugs
Interventions	Intervention Characteristics Nitrous oxide‐free ‐ A Name: Air ‐ Oxygen ‐ Propofol group Induction: Fentanyl 2 mcg/kg, vecuronium/rocuronium, TCI propofol 3.5 mcg/ml plasma target concentration Maintenance: TCI propofol 3.0 ‐ 4.0 mcg/ml plasma target concentration. Additional fentanyl bolus as required based on haemodynamics, surgical stimulation, FiO₂ 0.33, Local anaesthetic infiltration by surgeons (lignocaine/adrenaline), Atropine/neostigmine neuro‐muscular blockade reversal Recovery: PCA fentanyl with droperidol Other drugs used: Muscle relaxant = vecuronium/rocuronium (dose unspecified) for all participants Premedication: None Duration of anaesthesia (mins) = NR Nitrous oxide‐based ‐ A Name: Nitrous oxide‐Oxygen‐Propofol group Induction: Fentanyl 2 mcg/kg, vecuronium/rocuronium, TCI propofol 3.5 mcg/ml plasma target concentration Maintenance: TCI propofol 3.0 ‐ 4.0 mcg/ml plasma target concentration, additional fentanyl bolus as required based on haemodynamics, surgical stimulation, FiO₂ 0.33, local anaesthetic infiltration by surgeons (lignocaine/adrenaline), atropine/neostigmine neuro‐muscular blockade reversal Recovery: PCA fentanyl with droperidol Other drugs used: Muscle relaxant = vecuronium/rocuronium (dose unspecified) for all participants Premedication: None Duration of anaesthesia (mins) = NR Monitoring: Haemodynamics
Outcomes	Accidental awareness Details: Participants interviewed once able to obey commands and answer questions verbally in recovery room with regards to presence of dreams during anaesthesia. Furthermore, participants requested to fill in a paper questionnaire 24 hrs post‐op Questionnaire asked ‘Do you have memories of the surgery’ and ‘Did you dream something’ If answered ‘yes’ to awareness participant asked to state whether they: 1. Heard something 2. Felt pain 3. Felt vibration 4. Felt paralysed 5. Other No participants reported awareness
Identification	Country: Japan Setting: Operating theatre in single centre Authors name: Handa Institution: Tokyo Dental College Email: Not stated Address: Not stated
Aim of study	We investigated the frequency and the content of dreams during propofol anaesthesia in patients undergoing mandibular sagittal split ramus osteotomy (SSRO)
Notes	*Error in table 2 stating number of men/women in this subdivision – i.e. Table 2 states 40 men to 18 women in this branch of study group which contradicts the total number of men/women recruited and also what is stated in the main body of text Sponsorship source: NR
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: No method stated for randomization
Allocation concealment (selection bias)	Unclear risk	Comment: No information
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: No information
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: No information
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: No attrition
Selective reporting (reporting bias)	Low risk	Comment: Main aim of study to ascertain incidence and nature of dreaming during anaesthesia, however awareness stated as the other measured outcome in study methodology
Other bias	Low risk	Comment: None identified