Evaluating Hemidiaphragmatic Paralysis With Prolonged Neural Blockade From an Interscalene Brachial Plexus Block

This prospective observational study aims to evaluate the incidence of hemidiaphragmatic paralysis in patients receiving interscalene brachial plexus nerve block with prolonged neural blockade. English speaking American Society of Anesthesiologists (ASA) 1-3 patients ages 18-80 receiving prolonged interscalene nerve block will be randomized into 3 groups: first group receiving a perineural catheter infusing 0.2% ropivacaine; the second group receiving a single shot injection of 10mL liposomal bupivacaine (Exparel; n=20) plus 5 mL 0.5% bupivacaine and the third receiving 20mL liposomal bupivacaine plus 5mL bupivacaine (to be determined by the attending anesthesiologist).Primary outcome will be incidence of hemidiaphragmatic paralysis postoperative day 1 as measured by point of care (POCUS) ultrasound.