Residents' and attendings' opinions and impressions differ regarding what is expected from residents, what residents actually do, and what residents think they can do safely. The authors list factors affecting why and when supervisors trust residents to proceed without supervision. Future studies should address drivers behind entrustment decisions, correlations with patient outcomes, and tools that enable faculty to justify their entrustment decisions.

Ultrasound-guided interscalene brachial plexus block performed at the level of root C7 using 10 mL of ropivacaine 0.75% reduces the incidence of hemidiaphragmatic paresis.

Ultrasound-guided supraclavicular brachial plexus block, using 20 mL of 0.75% ropivacaine with the described technique, is not associated with hemidiaphragmatic paresis.