Compared with its IV counterpart, PN dexamethasone (5 mg) provides a longer duration of motor block, sensory block, and postoperative analgesia for US-guided infraclavicular block. Future dose-finding studies are required to elucidate the optimal dose of dexamethasone.

Costoclavicular and paracoracoid ultrasound-guided infraclavicular blocks resulted in similar onset times. Furthermore, no intergroup differences were found in terms of performance times and success rates. Future dose-finding trials are required to elucidate the minimum effective volume of local anesthetic for costoclavicular infraclavicular blocks. This trial was registered at www.clinicaltrials.in.th (Study ID: TCTR20160525001).

Background This randomized double-blinded trial compared the effect of intravenous and perineural dexamethasone (8 mg) on the duration of motor block for ultrasound (US)-guided axillary brachial plexus block (AXB). Methods Patients undergoing upper limb surgery with US-guided AXB were randomly allocated to receive preservative-free dexamethasone (8 mg) via intravenous (n = 75) or perineural (n = 75) administration. The local anesthetic agent, 1% lidocaine -0.25% bupivacaine (30 mL) with epinephrine 5 lgÁmL -1 , was identical in all subjects. Operators and patients were blinded to the nature of the intravenous and perineural injectate. A blinded observer assessed the block success rate (i.e., a minimal sensorimotor composite score of 14 out of 16 points at 30 min), block onset time, as well as the presence of surgical anesthesia. Postoperatively, the blinded observer contacted all patients with successful blocks to record the duration of motor block (primary outcome), sensory block, and postoperative analgesia. Results No intergroup differences were observed in terms of success rate, surgical anesthesia, and block onset time. RésuméContexte Cette étude randomisée à double insu portant sur le bloc axillaire du plexus brachial par échoguidage a comparé l'effet de la dexaméthasone (8 mg) administrée par voie intraveineuse ou périneurale sur la durée du bloc moteur. Méthode Des patients subissant une chirurgie des membres supérieurs sous un bloc axillaire du plexus brachial réalisé par échoguidage ont été randomisés à recevoir une dose de dexaméthasone (8 mg) sans agent de conservation par administration intraveineuse (n = 75) ou périneurale (n = 75). L'anesthésique local était identique pour tous les patients de l'étude, lidocaïne 1% et bupivacaïne -0,25% (30 mL) avec 5 lgÁmL -1

For ultrasound-guided costoclavicular block, the MEV90 of lidocaine 1.5% with epinephrine 5 μg/mL is 34 mL. Further dose-finding studies are required for other concentrations of lidocaine, other local anesthetic agents, and multiple-injection techniques.

Epidural waveform analysis (with pressure transduction through the needle) provides a simple adjunct to LOR for thoracic epidural blocks. Although its use was devoid of complications, further confirmatory studies are required before its routine implementation in clinical practice.

The sensory innervation of the clavicle remains controversial. The supraclavicular, subclavian, and long thoracic/suprascapular nerves, alone or together, may be responsible for pain transmission after clavicular fracture and surgery. Peripheral nerve blocks used to anesthetize the clavicle include superficial cervical plexus blocks, interscalene blocks, and combined superficial cervical plexus-interscalene blocks. Future (randomized) trials are required to determine which constitutes the best option for emergency department (fracture) and operating room (surgical fixation) settings.

Ultrasound guidance using a biplanar approach provides a similar success rate to fluoroscopy for C7 CMBB. However, US is associated with improved efficiency (decreased performance time and fewer needle passes).

Ultrasound guidance using a biplanar approach is a reliable imaging modality for C5 and C6 medial branch blocks.