Evaluation of Diaphragm Movement After an Interscalene Block

The purpose of this study is to evaluate the movement of the diaphragm after an interscalene block with liposome bupivacaine (LB) compared to interscalene block (IB) with bupivacaine. This study will evaluate if there is a possible prolonged phrenic nerve paralysis when using liposome bupivacaine in an interscalene block, using ultrasound.

This study will be run concurrently with two other studies comparing bupivacaine to Liposomal Bupivacaine in shoulder surgeries. We will use already randomized patients for our randomization process. For this study in particular we will use an ultrasound machine to scan the diaphragm of any patient who had an Interscalene Block for Total Shoulder Arthroplasy or Rotator Cuff Repair. Patients are to be scanned in an upright sitting position and scanned from a low intercostal or subcostal approach using the liver or spleen as an acoustic window. M Mode will be applied and the range of diaphragmatic movement from the resting expiratory position to deep inspiration (sigh test) will be recorded as was the range of diaphragmatic movement from resting expiratory position when quickly inspiring through the nose (sniff test). The blocks will be done regardless of the study as they are standard of care for pain control. The only intervention is ultrasound examination of the patient's diaphragm at baseline, 3 hours post block in recovery room and on post-operative day 1, and basic spirometry to record FEV1 and FVC via a portable spirometer at the same time points. If patients did stay in hospital on postoperative day 2 we would also evaluate their diaphragm function.

Inclusion Criteria: All patients age 18 years and older who are scheduled for shoulder surgery with interscalene block and remain in the hospital for more than 24 hours that are being randomized into a bupivacaine versus liposomal bupivacaine interscalene block study. Exclusion Criteria: Non English speaking patients.