Tedore 2009.

Methods	Randomized controlled trial
Participants	N = 220; adult; 110 male, 110 female; ASA 1‐3; surgery at or distal to elbow; American study
Interventions	Infraclavicular block. Localization method: ultrasound‐guided. Endpoint for injection: local anaesthetic spread. Dual‐injection technique: 75% of local anaesthetic injected around posterior cord, 25% injected around medial cord. Axillary block, transarterial. Localization method: surface landmarks. Endpoint for injection: dual‐injection technique with 75% of local anaesthetic injected posterior to artery and 25% injected anterior to artery. Continuous pressure applied with arm adducted for >5 minutes. Injectate in both blocks: mepivacaine 1.5% with 1:200,000 epinephrine and 0.1 mEq/ml of sodium bicarbonate, injected in a body weight‐adjusted volume of 40‐50 ml for weight <50kg and 50‐60 ml for weight >50kg Sedation for block: intravenous midazolam up to 5mg Intraoperative sedation: none
Outcomes	Adequate surgical anaesthesia, defined as lack of need for supplementation or general anaesthesia Block performance time Complications (assessed at two days and 10 days): pain, bruising, tenderness at block site, neurological symptoms Preference for same block in future
Notes	Primary aim of study was to assess neurological complications of the two techniques; not anaesthetic efficacy. There was no specified time between block completion and start of surgery, but it was probably within 15‐20 minutes.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “sealed envelope, computer‐generated random number method...”
Allocation concealment (selection bias)	Low risk	Quote: “sealed envelope, computer‐generated random number method...”
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Patient, operator, and assessor during block and the peri‐operative period was unblinded. The assessor of outcomes (patient satisfaction and complications) at 2 and 10 days following the block was blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	The exclusions of patients were explained clearly in the Results. The review authors believe the risk of bias is low
Selective reporting (reporting bias)	Low risk	All stated outcomes were reported
Other bias	Unclear risk	A weight‐based formula was used to calculate local anaesthetic volume, but the volumes were high rather than low. The patients were prepped for surgery 10‐15 minutes after completion of the block, and surgery commenced shortly thereafter; this shortened interval to surgery may have reduced the incidence of surgical anaesthesia.