EVALUATION OF PREEMPTIVE USE OF ANALGESIA OF THE SKIN, BEFORE AND AFTER LOWER ABDOMINAL SURGERY: A PROSPECTIVE, DOUBLE-BLIND, RANDOMIZED CLINICAL TRIAL

摘要

Background: Perioperative pain is prevalent and poorly treated. Apart from that it makes the recovery from surgery unpleasent, pain often remains as a residual side effect of surgery, even though the tissue healing is complete. An essential observation is that tissue injury and the resulting nociceptor barrage initiates a cascade of events that can indelibly alter pain perception. Preemptive analgesia is the concept of initiating analgesic therapy before the onset of the noxious stimulus so as to prevent the nociceptor barrage and its consequences. However, anticipated clinical potency of preemptive analgesia, though has firmly grounded in the neurobiology of pain, has not been yet realized. As data accumulates, it has become clear that clinical studies emulating those from the laboratory and designed around a relatively narrow definition of preemptive analgesia have been largely unsupportive of its use. Nevertheless, preemptive analgesic interventions that recognize the intensity, duration, and somatotopic extent of major surgery can help reduce perioperative pain and its longer-term sequelae. surgeons spend a lot of time treating the pain of lower abdominal surgery. Methods: A total number of 48 consecutive patients who were going to undergo elective lower abdominal surgery were randomly assigned in two groups of 24 each. In one group the patients received an injection of 0.5 % bupivacaine in the planned skin for incision just before lower abdominal surgery, and in the other group, they received an equal amount of 0.5% bupivacaine after the surgery had been done. Pain was objectified by a numerical visual pain score, in the 24 hours following the lower abdominal surgery. Results: There were no differences in postoperative pain scores on the visual analog scale (VAS): In groups 1and 2, VAS at hour 4 were 6.37±1.13 versus 6.29±1.19; At hour 8 were 5.54 ± 1.17 versus 5.37±1.09; and at hour 12 were 4.5 ± 1.31 versus 4.45 ± 1.1 respectively (P-value was not significant). There was not any difference between the main of morphine consumption between the two groups: at 12 hours, they were 11 ±3.5 versus 11.5 ±3.63; and at 24 hours, they were 17.87±5.88 versus 18.29 ±5.85 (P-value was not significant). Conclusions: The administration of local anesthesia prior to starting surgery does not appear to have any advantage over its postoperative administration in patients undergoing lower abdominal surgery.