Comparative Study of Postoperative Analgesic Effect of Morphine According to Timing of Injection

Shin, Sang Wook; Rho, Chang Gi; Kim, Hae Kyu

Abstract

BACKGROUND: The initiation of treatment seems to be important in provoking preemptive analgesia and to provide excellent postoperative pain control. To verify the effectiveness of postoperative analgesia and preemptive effects, pre-incisional and post-incisional epidural infusion of morphine and bupivacaine mixture were compared.
METHODS
Patients scheduled for elective upper abdominal surgery were divided into 2 groups. Each group received 2 mg of morphine in 10 ml of 0.25% bupivacaine as a bolus followed by 0.1 mg/ml/hr of morphine infusion in 0.125% bupivacaine epidurally. In post-incisional group, the epidural injection of mixture was started 15 minutes after skin incision and in pre-incisional group, the epidural infusion of mixture was started 15 minutes before skin incision. Each groups were evaluated in visual analogue scales (VAS) for pain, pain scores in movement, and total administered doses in postoperative 1, 2, 4, 8, 24, 48, and 72 hours and compared with each others.
RESULTS
There were no differences between pre-incisional and post-incisional start of continuous epidural mixture infusion of morphine and bupivacaine in VAS for pain, pain scores at movement, and total amount of infused doses for 72 hours postoperatively. Also, there were no differences in the incidence of complications and satisfactions of patients between two groups.
CONCLUSIONS
The continuous epidural mixture infusion of morphine 0.1 mg/ml/hr in 0.125% bupivacaine following a bolus dose of 2 mg morphine in 0.25% 10 ml bupivacaine has no difference in postoperative analgesic effect whether it starts after or before surgical incision.