Bupivacaine Versus Ropivacaine on Diaphragmatic Motility and Ventilatory Function
Status:
Completed
Trial end date:
2013-06-01
Target enrollment:
Participant gender:
Summary
Background: Outpatient continuous interscalene brachial plexus blocks are used to control
pain after shoulder surgery, with infusions of 0.125% bupivacaine or 0.2% ropivacaine. There
have been no studies comparing the effects of these two formulations. The major concern is
hemidiaphragmatic paresis, and since ropivacaine preferentially blocks sensory fibers, it may
cause less blockade of the phrenic nerve. This study was to evaluate the effects of
continuous interscalene brachial plexus infusions, with the hypothesis that respiratory
function is more affected by 0.125% bupivacaine than 0.2% ropivacaine, with equal effects on
pain relief.
Methods: All patients underwent baseline spirometry and ultrasound evaluation of
diaphragmatic excursion, followed by interscalene catheter placement for their surgery, then
randomized to receive a pump containing 0.2% ropivacaine or 0.125% bupivacaine. Patients
returned to the hospital the following day for spirometry, ultrasound reevaluation, and
evaluation of their pain level since discharge.