Boztug 2006

Methods	RCT
Participants	Turkey N = 50 ASA: I/II Gender: male/female 13/11, 11/12 Age: 45±11, 50±10 yrs Exclusion: any medication interaction with the central nervous system (antidepressant drugs, anti seizure drugs) or cardiopulmonary system (antihypertensive drugs, beta blockers), or a need for postoperative ventilation or other psychotropic drugs) Operation: Supratentorial craniotomy Duration of anaesthesia: 239±30, 222±32 min
Interventions	Sevoflurane guided by BIS (an A‐200 EEG monitor, Aspect Medical Systems), BIS value of 40‐60 during maintenance and of 60–70 during the last 15 minutes of surgery, Cn = 24 (BIS group) Sevoflurane inhalation guided by clinical signs (blood pressure and heart rate, somatic response), Cn = 23 (CS group)
Outcomes	Average end tidal concentrations (mean±SD) of sevoflurane Recovery times (min): ‐from end of surgery to first spontaneous breathing ‐from end of surgery to eye opening ‐from end of surgery to extubation PACU stay
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	A computer‐generated sequence of number was used
Allocation concealment (selection bias)	Low risk	A sealed envelope technique was used
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	"Three patients were excluded from the study due to disconnection of BIS probe (2) or artefact contamination (1)." The study has not been mentioned how to deal with the missing outcome data in the analysis
Selective reporting (reporting bias)	Low risk	All expected outcomes reported
Other bias	Unclear risk	The unblinded anaesthesiologist could potentially lead to ' learning contamination bias'
Blinding of patients?	Low risk	All patients were anaesthetized
Blinding of anaesthesiologists?	High risk	"...sevoflurane was adjusted in an effort to achieve a target BIS of 40‐60..." This indicates no blinding of the anaesthesia provider
Blinding of outcome assessors?	Unclear risk	The study has not mentioned clearly about the blinding of outcomes assessors