The Comparison of Postoperative Analgesic Effect of Morphine-Bupivacaine and Morphine-Bupivacaine-Clonidine Injected Intraarticularly after Knee Arthroscopy / 대한마취과학회지

BACKGROUND: Intraarticular opioids and local anesthetics may provide effective analgesia following knee arthroscopic surgery. However, there are conflicting results about the analgesic effects of a combination of morphine, bupivacaine and clonidine injected intraarticularly following knee arthroscopic surgery. The goal of this study was to determine whether clonidine added to an intraarticular morphine- bupivacaine combination provide an analgesic benefit. METHODS: Thirty patients scheduled for knee arthroscopic surgery under epidural anesthesia were selected and divided to two groups randomly. The patients in Group 1 received a combination of morphine 3 mg 0.25% bupivacaine 30 ml and patients in Group 2 received a combination of clonidine 3microgram/kg and morphine 3 mg in 30 ml of 0.25% bupivacaine intraarticularly following knee arthroscopic surgery. Postoperative pain was assessed using the visual analogue scale (VAS) and changes of arterial blood pressure, heart rate, requirement of additional analgesics, adverse effects and sedation scale were observed at 1, 2, 4, 8 and 24 hours after intraarticular injection. RESULTS: The VAS observed at 4, 8 and 24 hours after intraarticular injection were significantly lower in group 2 than group 1. Blood pressure and heart rate were not significantly changed between group 1 and group 2. The incidence of side effects, injection of additional analgesics and sedation were similar between the groups. There were no significant differences in hemodynamic changes, analgesic requirements, sedation scale or the increase of side effects between group 1 and group 2. CONCLUSIONS: The results suggest that the combination of intraarticular morphine 3 mg in 30 ml 0.25% bupivacaine plus clonidine provides significantly better analgesia than morphine 3 mg in 30 ml 0.25% bupivacaine alone following knee arthroscopy.

Effects of Mivacurium in the Strips of Rat Thoracic Aortic Rings / 대한마취과학회지

BACKGROUND: The hypotensive effects of muscle relaxants has traditionally been associated with a ganglion block and histamine release. However, it was exhibited that the ability of certain analogues of the steroidal muscle relaxant directly caused relaxation of isolated vascular smooth muscles. The ability of mivacurium to elicit a direct relaxant effect on vascular smooth muscle has been studied using isolated rat thoracic aortic rings contracted with phenylephrine (PE). METHODS: Each ring of the thoracic aorta was suspended on wire supports in a 20 ml tissue bath under 2 gm of resting tension. All tissues were bathed in a Tris Tyrode solution at 37oC and 100% oxygen was supplied. RESULTS: Mivacurium 3 X 10 5 M and 10 3 M inhibited PE induced contractions of the aortic rings significantly (P < 0.05) and shifted the cumulative concentration-effect curves of PE to the right. The maximum contractile response from 81.9% to 55.0% (with PE 10 6 M) was the same as that seen with mivacurium 10 3 M pretreatment. Relaxation of aortic ring with mivacurium 10 3 M was not reversed with L-NAME pretreatment. Methylene blue reversed the relaxation of the aortic rings with mivacurium 10 3 M and shifted the cumulative concentration-effect curve of PE to the left. Indomethacine enhanced the relaxation of the aortic rings with mivacurium 10 3 M and shifted this curve to the right. Mivacurium 10 3 M inhibited the influx of extracellular Ca2+. CONCLUSIONS: The results suggest that the relaxation effects of mivacurium is related with the endothelium and at least, in part, cyclooxygenase inhibition and guanylate cyclase activation are related with this relaxation effect. Also, mivacurium inhibited extracelluar calcium influx.