| Background:Dexmedetomidine, an alpha 2-adrenergic and more a2 specificity agonist, has dose-dependently sedative and analgesic properties, which is associated with reduction of anesthetics. Recently there are many articles reported the anti-inflammation of dexmedetomidine. Inflammation plays a role in the pathogenesis of postoperative cognitive dysfunction. The present study was designed to show the effects of dexmedetomidine infusion on perioperative inflammatory response and hemodynamics, propofol, opioids consumption when used for general anesthesia in patients undergoing spinal surgery. The incidence of postoperative cognitive dysfunction after spinal surgery in elderly was evaluated.Methods:Forty-five elderly patients aged 65-80 years old, ASAⅠ-Ⅱpatients were randomised into three groups:I (control group),Ⅱ(1.0ug/kg loading + 0.5ug/kg-h maintenance group),Ⅲ(1.Oug/kg loading + 1.0ug/kg-h maintenance group), each group had 15 cases. Patients in groupⅠdid not use dexmedetomidine, patients in GroupⅡandⅢboth receivedⅣdexmedetomidine 1.0 ug/kg over 15 minutes and a continuous infusion dose of 0.5ug/kg-h during operation in groupⅡand 1.0ug/kg-h during operation in groupⅢ. Three groups received midazolam 0.04～0.05mg/kg, fentanyl 4～6ug/kg, vecuronium 0.1mg/kg, and propofol 0.5～1 mg/kg for induction. Maintenance of anesthesia: Fentanyl was given to 5～10μg/kg in the first half couse of the surgery, and remifentanil, propofol and vecuronium were given according to the haemodynamics, maintaining the AEP 30～40 throughout the procedure. The plasma levels of IL-6, TNF-αwere measured by Enzyme Linked Immunosorbent Assay and the peripheral blood monocytes nuclear factor-κB activation was detected by flow cytometry-based method at T1(before surgery), T2 (end of surgery) and T3(24 hours after surgery). Systolic blood pressure, heart rate, AEP index and propofol, opioids consumption were aslo recorded perioperation.A battery of neuropsychological tests was performed and scored preoperatively and 7 days after operation.Z-combined score was applied to diagnosis of cognitive dysfunction.Patients had cognitive dysfunction if two Z score in individual or the combined Z score were 1.96 or more.Results:1.There were no significant differences in the aspects of age, weight, gender, ASA degree, education, the time of operation and blood loss among groups.2.The incidence of postoperative cognitive dysfunction in groupⅠwas 26.7%(4/15), in groupⅡwas 20%(3/15) and in groupⅢwas 0%(0/15).The incidence of postoperative cognitive dysfunction in groupⅡwas lower than that of groupⅠ,but there was no statistical difference between the two groups(P>0.05). The incidence of postoperative cognitive dysfunction in group III was significantly lower than that of group I and group II (P<0.05).3.The operative fentanyl requirements were significantly lower in GroupⅡ(0.62±0.13 mg),Ⅲ(0.59±0.13mg)than that in GroupⅠ(0.74±0.16mg) (P<0.05). The operative remifentanyl requirements were significantly lower in GroupⅡ(0.91±0.59mg),Ⅲ(0.66±0.50mg) than that in GroupⅠ(1.26±0.59mg) (P＜0.05). The operative propofol requirements were significantly lower in GroupⅡ(477.20±171.43mg),GroupⅢ(426.40±197.23mg) than that in GroupⅠ(771.92±268.39mg) (P<0.05).4.There were no statistical difference among groups in systolic blood pressure and heart rate perioperative. But the incidence of hypertension and sinus bradycardia were higher in patients used dexmedetomidine.5.There were no statistical difference among groups in the plasma levels of IL-6, TNF-αand the peripheral blood monocytes nuclear factor-KB activation. But the plasma levels of IL-6 were lower in groupⅡ(6.28±4.12),Ⅲ(13.33±18.22) than that in GroupⅠ(25.32±33.31) (P＜0.05).Conclusion:1. The study showed that dexmedetomidine, with a loading dose of 1.0ug/kg and maintenance dose of 0.5ug/kg-h or 1.0ug/kg·h, could decrease the propofol, fentanyl and remifentanyl consumption and seemed to be an effective adjunct to anesthetic agents during major elective open spinal surgery in elderly patients. 2.Dexmedetomidine could reduce the incidence of postoperative cognitive dysfunction in elderly patients when used in spinal surgery. |
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