Objective. To compare the analgesic effect of combined
intrathecal morphine and dexmedetomidine
with either drug alone for postoperative analgesia in
patients undergoing major abdominal cancer surgery.
Methods. Ninety patients were allocated to receive
intrathecal 10mg bupivacaine 0.5% (bupivacaine
group, n530), 10mg bupivacaine 0.5% and 0.5mg
morphine (Morphine Group, n530), or 10mg bupivacaine
0.5%, 0.5mg morphine and 5 mg dexmedetomidine
(morphine-Dex group, n530). The groups were
compared with time to first postoperative analgesia,
iv patient-controlled analgesia (PCA) morphine consumption,
pain scores, hemodynamics, sedation,
and adverse events in the first 48h postoperative.
Results. The time to first use of morphine PCA was
longer in morphine (22.1365.21h, P50.000) and
morphine-Dex (23.4664.69h, P50.000) groups
compared with bupivacaine group (0.5060.09h).
Dexmedetomidine addition increased the duration
of intrathecal morphine (ITM) analgesia by 1.33 h
(P50.485). Morphine consumption was less in morphine
(10.8362.96 mg, P50.000) and morphine-
Dex (11.0063.32 mg, P50.000) groups than in
bupivacaine group (27.564.30 mg), with a nonsignificant
difference between morphine and morphine-
Dex groups (P50.375). Morphine and
morphine-Dex groups showed lower pain scores
(P< 0.001). Intraoperative blood pressure and heart
rate were lower in morphine and morphine-Dex
groups (P< 0.05) with no significant difference between
groups in postoperative hemodynamics.
Patients in bupivacaine group showed a higher incidence
of postoperative nausea (P< 0.03) and vomiting
(P < 0.01), while patients in morphine and
morphine-Dex groups had a higher incidence of
pruritus (P< 0.02).
Conclusions. Our results do not support improved
analgesia with the combination of intrathecal morphine
and dexmedetomidine, despite the absence
of significant adverse effects.