Comparison of epidural Morphine Versus Intramuscular Morphine for postoperative analgesia

Objective: To compare effects and side effects or complications of epidural versus intramuscularly administered morphine for relieve of postoperative pain. Patients and methods: In the first group (epidural) analgesia is achieved by application of morphine through epidural catheter. To the amount of morphine is added physiological solution until 10 ml of total volume of the mixture is achieved. This mixture is given to 150 patients, by epidural route before the exit from the operation room. Epidural catheter is removed after 48 hours. Second group (intramuscular) analgesia is realized by application of 10 mg of morphine by intramuscular route. Morphine is injected at the end of surgery. Pain is assessed with combination of verbal categorical scale and visual analog scale. Verbal categorical scale used is 8 points scale and contains words of Tursky: 0 no pain, 1 very low pain , 2 week pain, 3 mild pain , 4 moderate pain , 5 strong pain, 6 severe pain, 7 untolerated pain. Awareness is assed during first 24 hours. For this Reynolds 4 points scale is used: awaked 1, somnolent 2, sleepy 3, deep sleep 4. Results: Pain assessed by visual analog scale (VAS) is 15.17-29.62 in the epidural group patients versus 26.39-70.83 in intramuscular group. Variation of respiration rate in both groups is not significant 22.21 ±4.23 and 23.98 ±2.72 in minute, in epidural and intramuscular morphine groups, respectively. PaCO2 and PaO2 values are similar without significant variation 35.34 ±4.72 mmHg in the epidural morphine group and 31.3 ±3.21 mmHg in intramuscular morphine group. Conclusion: Epidural administration of morphine provides better analgesia in quality, since it is deeper, longer in duration and with less inhibitory supra-spinal actions when compared to intramuscular administered morphine.