Journal of clinical anesthesia
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Outpatient continuous interscalene brachial plexus blocks containing bupivacaine or ropivacaine are commonly used to control pain after shoulder surgery. Interscalene blocks cause hemidiaphragmatic paresis. Because ropivacaine preferentially blocks sensory fibers, it may cause less blockade of the phrenic nerve. The purpose of this study was to evaluate the effects of 2 common continuous interscalene brachial plexus infusions: 0.125% bupivacaine vs 0.2% ropivacaine. The study hypothesis is that respiratory function will be less attenuated using ropivacaine than bupivacaine without affecting pain relief. ⋯ There was no difference in respiratory dysfunction or opioid requirements between interscalene continuous peripheral nerve blocks with 0.125% bupivacaine or 0.2% ropivacaine. Further study is required to identify anesthetic infusates that will control pain while decreasing the attenuation of pulmonary function.