The effects of arm position on onset and duration of axillary brachial plexus block.

Background: We assessed the effects of arm position after block performance on success rate, onset time, and duration of axillary block (AXB).
Methods: After performing AXB, patients were randomized into two groups: group adduction in which the arm was immediately placed in adduction along the body and group abduction in which the arm remained in abduction. These positions were maintained until the block was achieved.
Results: The sensory and motor blocks onset time were significantly shorter in the abduction group compared with that in the adduction group and their duration was significantly prolonged (P < 0.001).
Conclusion: Maintaining the arm in abduction after performing AXB allows a shorter onset time and a prolongation of the sensory and motor blocks.