We evaluated the
postoperative pain relief and side-effects of continuous epidural infusion of three
analgesic regimens following major thoracic and/or abdominal surgery. One hundred and twenty patients were randomly divided into three treatment groups: (1) 0.25% or 0.5%
bupivacaine at a rate of 3-7 ml.hr(-1), (2) 0.01%
morphine at a rate of 1-2 ml.hr(-1), (3) a combination of 0.125% or 0.25%
bupivacaine and 0.0025% or 0.005%
morphine at a rate of 2-4 ml.hr(-1). The study continued for the first 48 postoperative hours. The effect of
pain relief was evaluated by assessment of the further requirement for parenteral
analgesics. Sixty-four percent of the patients given
bupivacaine, 56% of the patients given
morphine and 80% of the patients given the combination required no supplemental
analgesics. Continuous epidural infusion of
bupivacaine was associated with
hypotension (21%) and with
numbness and weakness of hands or legs (18%). Continuous epidural infusion of
morphine was associated with
pruritus (18%) and with peristaltic depression (12%). The combination regimen was associated with
pruritus (17%) and with drowsiness (14%). We conclude that the combination of
bupivacaine and
morphine significantly provides superior
analgesia with less deleterious complications compared with either
bupivacaine or
morphine alone.