It is unclear whether addition of opioids to epidural solutions for postoperative analgesia
is beneficial. In this multicenter randomized double-blinded trial, we aim to test the
primary hypothesis that epidural solutions containing only bupivacaine are as effective as
solutions containing both bupivacaine and fentanyl in promoting analgesia in patients
recovering from open abdominal surgery. We also aim to assess the incidence of
epidural-induced hypotension, the difference in patient-reported opioid side-effects between
the two groups. If we demonstrate no clinically important difference between the two
interventions, clinicians will be able to substantially reduce the amount of opioids patients
receive during their postoperative recovery, and potentially decrease the associated high
incidence of opioid adverse effects in post-surgical patients.