Frederiksen 2010.

Methods	Randomized controlled trial
Participants	N = 80; adult (19‐80 yrs); 36 male, 44 female; elective or emergency elbow/forearm/hand surgery, Danish study
Interventions	Infraclavicular block (Dingemans 2007). Localization method: ultrasound‐guided. Endpoint for injection: U‐shaped distribution of local anaesthetic posterior to axillary artery. Axillary block (Chan 2007). Localization method: ultrasound‐guided. Endpoint for injection: Local anaesthetic distribution around visible nerves, or if nerves not visible, around the axillary artery. Injectate divided equally between each of 4 nerves: median, ulnar, radial, musculocutaneous. Injectate in both blocks: mixture of ropivacaine 0.75% and mepivacaine 2% in a 1:1 ratio, with 1:200,000 epinephrine, in volume of 0.5ml/kg (maximum of 50 ml) Sedation for block: none Intraoperative sedation: intravenous midazolam if requested by patient
Outcomes	Adequate surgical anaesthesia, defined as a sensory score of 1 or 2 in nerves distal to elbow at 30 minutes Complete motor block, defined as no movement in hand/wrist/elbow Number of needle passes Block performance time Block onset time Time to readiness for surgery, defined as sum of block performance and onset times Block‐associated pain, scored on a 0‐100 VAS Preference for a similar block in the future Complications: pneumothorax, dysaesthesiae, vascular puncture
Notes	Study authors state that the infraclavicular block is the preferred approach in their institution and that limited experience with the axillary block may have affected outcomes. A weight‐based formula was used to calculate local anaesthetic volume: 0.5ml/kg up to a maximum of 50ml. The use of lower volumes (<40ml) may have reduced infraclavicular block success. Mean and standard deviation data for some outcomes was obtained from the corresponding author by email correspondence. Abbreviations: VAS = visual analogue score
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “computer‐generated random number”
Allocation concealment (selection bias)	Low risk	Quote: “sealed envelope method”
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: “a blinded observer” performed all assessments, and performed all supplementary blocks Only the outcome assessor was blinded. Further blinding not feasible. The review authors do not believe this will introduce significant bias
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing data
Selective reporting (reporting bias)	Low risk	The data for surgical and sensory block success were not explicitly reported in the published study, but this information was obtained from the study authors
Other bias	High risk	Quote: “The infraclavicular approach is our standard technique for hand/forearm surgery, although the AX block is more often used in arthritic, obese or muscular patients. We teach our residents the IC block as the primary approach. Most blocks in this study were performed by the residents, although the number of AX blocks performed by the residents in this study is lower than the number of IC blocks. Their limited experience with the axillary approach might have affected the performance times and numbers of needle passes. All incomplete AX blocks occurred among the first half of the patients included, which supports this speculation”