Viera 2010.

Methods	Parallel group RCT.
Participants	In the USA, 120 ASA I‐III participants 18 years or older undergoing elective shoulder arthroscopy with interscalene brachial plexus block were included. Participants with a contraindication to bupivacaine, epinephrine, clonidine or dexamethasone as well as pregnant participants were excluded.
Interventions	Block All participants underwent ultrasound‐guided supraclavicular block with bupivacaine 5 mg/ml + epinephrine 5 microgram/ml and clonidine 75 microgram/ml. Dexamethasone/placebo Dexamethasone group: dexamethasone 8 mg perineurally. Placebo group: normal saline 2 ml perineurally. Intraoperative anaesthesia/analgesia Anaesthesia was induced with propofol and maintained with sevoflurane, desflurane or propofol with nitrous oxide after the block. Postoperative anaesthesia/analgesia Participants were prescribed hydrocodone, oxycodone or hydromorphone.
Outcomes	Outcomes of interest for the review Intensity of pain measured on an 11‐point VAS at 24 and 48 hours after surgery. Duration of sensory and motor block. Participants were given a diary to record the time at which they felt the sensory and motor block had resolved based on increase in pain, sensation and strength in the arm. Participant satisfaction with pain placebo measured on an 11‐point VAS Other outcomes Intensity of pain on admission to PACU, 1 and 2 hours after surgery and on discharge from PACU.
Notes	Funding: departmental funding from the Department of Anesthesiology, Baystate Medical Center, Springfied, Massachuttes. Conflicts of interest: none.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random sequence was computer‐generated.
Allocation concealment (selection bias)	Unclear risk	No indication of how group allocation was concealed.
Blinding of participants (detection bias)	Unclear risk	No indication whether participants were blinded.
Blinding of personnel (detection bias)	Unclear risk	No indication whether personnel were blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No indication whether outcome assessors were blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Low risk	No protocol available. All outcomes reported as stated in the methods section.
Other bias	High risk	Sample size was 88; however, 120 participants were enrolled in order to obtain reliable data from 88 participants.