Liu 2005.

Methods	RCT, parallel design
Participants	90 patients, ASA I ‐ II, scheduled for forearm, wrist or hand surgery Exclusions: patient refusal, allergy to local anaesthetics, pre‐existing neuropathy, dementia
Interventions	Ultrasound (double injection) (n = 30) versus ultrasound (single injection) (n = 30) versus nerve stimulation (double injection) (n = 30) Axillary brachial plexus block with 0.5 ml/kg 1.5% lignocaine with epinephrine (5 µg/kg) in nerve stimulation group and 30 ml 1.5% lignocaine with epinephrine (5 µg/kg) in ultrasound groups Ultrasound: 12 MHz probe (Hawk model 2102, B‐K medical); endpoint ‐ visualization of local anaesthetic spread around axillary artery. Either 1 injection (superior to artery) or 2 injections (superior and inferior to artery) Nerve stimulation (Stimuplex): 2 Hz; endpoint ‐ stimulation of median nerve and radial nerve. No current thresholds given
Outcomes	Time taken to perform block ("from needle puncture on the skin guided by nerve stimulator or the application of the ultrasound on the skin to the completion of the lidocaine injection") Adequacy of block (defined as "loss of pinprick sensation", evaluated at 40 min after injection) Block supplementation ("Anesthetic failure was managed with supplemental intravenous analgesics or general anesthetics as appropriate") Complications
Notes	1 practitioner performed all blocks, experience not given For the purpose of analysis of Adequacy of block and Supplementation rate, we combined the data for the double and single injection ultrasound groups For the purpose of analysis of Time to perform block, we took data only from ultrasound (double injection) versus nerve stimulation (double injection)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomization table
Allocation concealment (selection bias)	Unclear risk	No details
Blinding of participants and personnel (performance bias):adequacy of block, need for supplementation	High risk	Not possible to blind anaesthetist
Blinding of participants and personnel (performance bias):Complications	High risk	Not possible to blind anaesthetist
Blinding of participants and personnel (performance bias): time outcomes	High risk	Not possible to blind anaesthetist
Blinding of outcome assessment (detection bias): adequacy of block, supplementation of block	Low risk	Assessment done by anaesthetist unaware of group allocation
Blinding of outcome assessment (detection bias): Complications	Low risk	Assessment done by anaesthetist unaware of group allocation
Blinding of outcome assessment (detection bias): time outcomes	Low risk	Assessment done by anaesthetist unaware of group allocation
Incomplete outcome data (attrition bias) All outcomes	Low risk	No withdrawals or exclusions
Selective reporting (reporting bias)	Unclear risk	Published protocol not sought
Baseline characteristics	Low risk	Baseline characteristics comparable
Funding sources	Low risk	No apparent external funding
Operator expertise	Unclear risk	Same anaesthetist for all blocks