Comparison of the effects of peroperative dexmedetomidine, midazolam and ondansetron in patients receiving postoperative patient controlled morphine

Objective: This study was designed to compare the effects of dexmedetomidine, midazolam and ondansetron on postoperative analgesia and antiemetic effect in patients receiving postoperative patient controlled morphineMethods: Following approval of drug research ethical committee and patient written consent, 120 patients undergoing elective laparotomy were recruited to study. Ten minutes before the induction of anaesthesia, following loading dose, the first group received dexmedetomidine (0.2 µg/kg/hr); the second group received midazolam (0.02 mg/kg/hr); the third group received ondansetron, (0.5 mg/hr) and the fourth group received 5 cc/hr of saline. At the closure of peritoneum, all patients were given a loading dose of morphine (0.1 mg/kg) and a patient-controlled analgesia (PCA) deviceResults: Recovery times were found significantly longer in dexmedetomidine group compared to ondansetron and placebo groups. Pain and patient comfort scores were similar and there was no significant difference between groups. Sedation scores were significantly higher in dexmedetomidine group compared to ondansetron and placebo groups. Morphine consumption was significantly lower at 6, 12 and 24 hours in ondansetron group and lower only at 12 hour in dexmedetomidine group, postoperatively. At the first 24 hour, the incidence of nausea and vomiting was significantly lower in all study groups than in saline group.Conclusion: In patients receiving PC morphine after elective laparotomy, dexmedetomidine, midazolam and ondansetron, given before the induction of anaesthesia to till the postoperative 24th hour provided lower incidence of postoperative nausea and vomiting at the first two hour than saline group. Although intubation quality, sevoflurane consumption, extubation time and VRS scores were similar between groups, morphine consumption after 24 hour was significantly lower in dexmedetomidine and ondansetron groups than saline and midazolam groups.