Dose Effects of Epinephrine to Intrathecal Morphine for Postoperative Analgesia

So, Keum Young; Park, You Jin

Abstract

BACKGROUND: Epinephrine itself interacts with adrenergic receptors to block pain transmission pathways. Intrathecal co-administration of morphine and epinephrine results in a near maximal increase in the nociceptive threshold. This study was designed to investigate the influence of different dosages of epinephrine on the postoperative pain relief through intrathecal morphine in lower extremity surgery. METHOD: Thirty patients, ASA physical status I or II, undergoing orthopedic surgery of lower extremities were selected and randomly divided into two groups as follows: Group I (n=15); bupivacaine, morphine 0.2 mg with epinephrine 0.12 mg. Group II (n=15); bupivacaine, morphine 0.2 mg with epinephrine 0.2 mg. With patients lateral in the decubitus position, a 25-gauge spinal needle was introduced into the subarachnoid space. Patients were turned to the supine position, and sensory levels were checked by pin-prick tests at the midclavicle level , and the degree of motor block by Bromage scale every 5 minutes. The two segment regression time was measured every 20 minutes. During the postoperative day and the second day, their analgesic effects were evaluated by use of the visual analogous scale (0~10). The side effects were also evaluated.
RESULTS
There were no difference between both groups in sensory level and two-segment regression time. Motor block in 5, 10, 15 minutes was more intense in group II. Also, there were no significant difference in the analgesic effects and the incidence of side effects, such as nausea or pruritus.
CONCLUSION
There were no significant dose effects of epinephrine added to intrathecal morphine for postoperative pain relief undergoing lower extremities surgery.