Koscielniak‐N 2009.

Methods	Randomized controlled trial
Participants	N = 120; adult (age 45‐51 years); 79 male, 41 female; ASA 1‐2; elective or emergency surgery of elbow/forearm/hand; Danish study
Interventions	Infraclavicular block (Dingemans 2007). Localization method: ultrasound‐guided. Endpoint for injection: local anaesthetic spread. 50% of local anaesthetic was injected posterior to the axillary artery, and the rest was injected with needle repositioning to achieve U‐shaped spread posterior to the artery. Supraclavicular block. Localization method: ultrasound‐guided. Endpoint for injection: 50% of local anaesthetic was injected superficial to plexus, and the rest was injected with needle repositioning to obtain circumferential spread around the plexus/nerves. Injectate in both blocks: mixture of ropivacaine 0.75% and mepivacaine 2% in a 1:1 ratio in a volume of 0.5 ml/kg (range 30‐50 ml) Sedation for block: intravenous fentanyl 25‐50 mcg and midazolam 1‐2 mg Intraoperative sedation: none used
Outcomes	Adequate surgical anaesthesia by 30 minutes, defined as anaesthesia or analgesia of the five nerves distal to the elbow. Complete sensory block of individual nerves, defined as anaesthesia or analgesia of axillary, medial brachial cutaneous, medial antebrachial cutaneous, radial, ulnar, median, musculocutaneous nerves. Block performance time, defined as from insertion of needle to removal. Does not include ultrasound scanning time. Block onset time. Complications: phrenic nerve palsy (clinical diagnosis), pneumothorax, vascular puncture, Horner's syndrome, neurological deficits, systemic toxicity. Preference for a similar anaesthetic in the future.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “computer‐generated random numbers”
Allocation concealment (selection bias)	Low risk	Quote: “closed envelope method”
Blinding (performance bias and detection bias) All outcomes	Low risk	Quote: “single‐blinded” study Patient, operator and block observer were unblinded. However it is not explicitly stated as to whether assessor for other outcomes was blinded. Based on previous work by primary author, this is likely to have been done
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: “Three patients (two in the I group and one in the S group) were lost to follow‐up.” This only impacts outcomes of transient neurological deficit and patient preference for a similar anaesthetic in the future. The review authors do not believe this will introduce bias
Selective reporting (reporting bias)	Low risk	All major and important outcomes reported
Other bias	High risk	Quote: “We speculate that the poorer efficacy of the supraclavicular blocks in our patients was caused by lower experience with this approach and a higher number of colleagues performing the block. Our standard blocking technique for hand and/or forearm surgery is infraclavicular, although obese patients mostly receive supraclavicular or axillary blocks. Although staff anaesthesiologists listed as authors were skilled in both approaches, the infraclavicular approach is better known by other colleagues and the residents who carried out the blocks under supervision.”