BACKGROUNDS AND OBJECTIVES: Although initial studies of preemptive analgesia showed that preoperative blockade with local anaesthetics or pre-operative administration of systemic opioids was more effective in reducing postoperative pain than control conditions involving no treatment, the result of subsequent investigations comparing the effects of pre-operative treatment with the same treatment initiated after surgery have produced inconsistent results.The reasons for the lack of consistency are not clear. Studies about the relationship of preemptive analgesia and both analgesic consumption and surgical stress response are limited. The purpose of this study was to evaluate the effect of preemptive intravenous morphine on both postoperative analgesic consumption and surgical stress response. METHODS: Sixty patients, ASA lor II, aged 20-60, undergoing total abdominal hysterectomy plus bilateral salphingo-opherectomy were randomly assigned to three groups of 20 patients. Group I (n = 20) received 0.15 mg.kg-1 of morphine following induction and placebo saline during peritoneal closure. Group II (n = 20) received placebo saline following induction and 0.15 mg.kg-1 of morphine during peritoneal closure. Group III (n = 20) received placebo salin, both during induction and peritoneal closure. Blood cortisol, glucose levels and leukocyte count were measured in the pre and postoperative period. RESULTS: Postoperative total morphine consumption was significantly lower in group I compared with group III (p < 0.001). In all groups, plasma cortisol levels increased significantly within 4 h of surgery as compared to pre-op values (p < 0.001). Plasma glucose levels also increased significantly in all groups of the postoperative at 30 minutes and 8 hours period (p < 0.001). Postoperative leukocytosis was observed in all groups and the leukocyte count was significantly greater during the postoperative period than preoperative values (p < 0.001). CONCLUSIONS: Preemptive intravenous morphine 0.15 mg.kg-1 has decreased total morphine consumption but has failed to supress the surgical stress response.
ANALGESIA, Preemptive, Postoperative; ANALGESICS, Opoids
