Effects Of Dexmedetomidine On Cognitive Dysfunction In Elderly Patients With Esophageal Cancer After Radical Resection

Objective: This study observed the effect of one lung ventilation on cognitive dysfunction in elderly patients with esophageal cancer after radical resection,to explore whether the perioperative continuous infusion of dexmedetomidine changes inflammatory factors and cerebral oxygen metabolism rate and improves the postoperative cognitive dysfunction in patients.Methods: Chose 60 elderly patients with esophageal cancer from Southwest Medical University Affiliated Hospital of traditional Chinese Medicine Department of anesthesia from January to September of 2014,ages from 65 to 80 years old,the gender is not limited.ASA grade I to II,and 60 patients were randomly divided into dexmedetomidine group（D group,n=30）and saline control group（C group,n=30）.D group was given 1μg/kg intravenous micro pump infusion of dexmedetomidine before induction of anesthesia,the infusion time was 15 min,and intravenous infusion of 0.5μg·kg·h was maintained until 15 minutes before the end of surgery.At the same time C group was given the same amount of normal saline.The two group received fentanyl,propofol and cisatracurium in anesthesia induction.Double lumen endobronchial intubation was performed when the bispectral index decreased to 40,After successful intubation,the anesthesia machine controlled ventilation,and the mode was capacity conversion control mode.With continuous infusion of propofol,remifentanil,propofol,1 2% sevoflurane inhalation to maintain the appropriate depth of anesthesia（Bispectral index ranges from 40 to 60）.One lung ventilation time was controlled in 2 to 3h,and the blood oxygen saturation is controlled in more than 95%.15 minutes before the end of the operation,stopped the use of inhalation anesthetics and muscle drug,and accessed analgesia pump.Postoperative analgesia used disposable electronic infusion pump of 100 ml,and the using time was 48 hours.Formula:D group used 0.08μg·kg·h dexmedetomidine+0.04μg·kg·h sufentanil+10mg tropisetr-on;C group used 0.04μg·kg·h sufentanil+ 10 mg tropisetron.Analgesia pump loading dose was 6 ml,and background infusion rate was 2 ml/h,and Self controlled pressing was 2 ml/h,and the locking time was 15 min.Observation indicator: Respectively measured scores of Mini Mental State Scale（MMSE）,pain VAS and calm Ramsay on the first day before the operation（T₀）,the first day after the operation（T₁）,the third day after the operation（T₂）and the seventh day after the surgery（T₃）.Meanwhile,IL-6and S-100β protein were measured before induction（T_a）,at the moment after the operation（T_b）,during the 24 hours after the operation（T_c）,and during the 72 hours after the operation（T_d）,extracted serum IL-6 and S-100βprotein in venous blood to determine,and extracted blood gas of jugular vein blood and arterial blood to analyze,based on the Fick formula to calculate the rate of cerebral oxygen metabolism rate（CMRO₂）.Results:（1）Compared with group C,MMSE score of group D in T₁ and T₂ increased significantly（P<0.05）,the incidence of POCD and pain VAS scores were significantly lower（P<0.05）;（2）When in T_b and T_c,IL-6 of group D is obviously less than the compared group（P<0.05）,and the S-100βprotein in Tb was significantly lower than that in the group C（P<0.05）;（3）Compared with group C,the difference of blood oxygen content and cerebral oxygen metabolism rate significantly decreased of group D（P<0.05）;（4）Sedation Ramsay score in T₁ of group D was obviously higher than group C（P<0.05）,No respiratory depression occurred in the two groups;.Conclusions:（1）The dose of dexmedetomidine in the study can bring synergistic effects of sedation and analgesia,sedation depth is suitable,and there will be no respiratory depression;（2）The application of dexmedetomidine can reduce IL-6,S-100 β protein and cerebral oxygen metabolism rate,while reducing the incidence of POCD.