Bekker 2008.

Methods	Study design: randomized controlled trial (2 arms) Study duration: not reported Study setting: hospital, single centre, USA
Participants	Adults undergoing elective craniotomy (n = 72) Inclusion criteria Adults undergoing elective craniotomy Exclusion criteria Significant laboratory abnormalities Advanced heart block Allergy to study drugs Mean age, range (years) 42 (18 to 65) Numbers allocated to each arm Group intervention: not reported but 28 included in analysis Group control: not reported but 28 included in analysis Male gender Group intervention: 17/28 Group control: 20/28
Interventions	Technique and timing Dexmedetomidine by intravenous infusion as an initial bolus of 10 mcg/kg/hr for 10 minutes and then 5 mcg/kg/hr, commenced after intubation and continued until 20 minutes before the end of surgery versus saline infusion Dosage Bolus of 10 mcg/kg/hr for 10 minutes and then 5 mcg/kg/hr
Outcomes	Primary Haemodynamic response to surgery Secondary Analgesic requirement in the postoperative recovery unit Anti‐emetic requirement in the postoperative recovery unit Antihypertensive requirement in the postoperative recovery unit Adverse events ‐ hypertension (systolic blood pressure > 130 mmHg), hypotension (systolic blood pressure < 90 mmHg), tachycardia (heart rate < 50), bradycardia (heart rate > 90)
Notes	Funding None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: ''patients scheduled for elective craniotomy were randomly assigned to receive either sevoflurane–opioid or sevoflurane–opioid–DEX anaesthesia''. However, the method of randomization was not described.
Allocation concealment (selection bias)	High risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: ''the anaesthetic was managed by experienced neuroanaesthesiologists blinded to DEX or placebo regimen''. There was no mention of blinding participants, however as the infusion was started after the participants were anaesthetized and stopped before they were woken up, the lack of patient blinding is very unlikely to have had a significant impact on the results.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: ''anesthesiologist and nurses who were unaware of anaesthetic technique managed postoperative recovery of the study patients''.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	16 participants were recruited but not included in the final analysis. Of these, 1 from each of the study groups was removed from analysis, 1 because of bleeding and the other because they remained intubated after surgery. The remaining 14 recruited participants were not included in the final analysis as technical problems precluded recovery of their data.
Selective reporting (reporting bias)	Low risk	Outcomes reported as specified
Other bias	Unclear risk	Small study